Journal of Composites Science doi: 10.3390/jcs10100548

Authors: Traian Zaharescu Violeta Mangalagiu Radu Mirea

This study analyzes the stabilization effects of silica nanoparticles and rosemary extract on polypropylene during accelerated degradation caused by exposure to γ-rays. The accurate procedures involved in the mitigation of oxidative degradation (isothermal and nonisothermal chemiluminescence) allow for the identification of the appropriate filler concentration and cooperative effect with rosemary extract, which significantly improves PP durability. The examination of the stability attained by PP modification reveals strictly differentiated values of activation energies: 100 kJ mol−1 to 145 kJ mol−1 required for nonirradiated PP as pristine material and highly modified compounds by the couple, respectively, and 79 kJ mol−1 to 143 kJ mol−1 required by the samples after receiving 50 kGy. This indicates the efficient protection identified in this investigation for PP against oxidative degradation during operation under very harsh energetic conditions. The contribution of the studied additives is illustrated by the several-fold improvement of the kinetic parameters, such as the oxidation induction time, that describe material protection. This feature may be appropriately extended to the valorization of PP waste for recycling. While silica nanoparticles act as an efficient scavenger by the trapping of radicals in the superficial lattice defects, rosemary extract provides the protective role of its polyphenol components through the replacement of hydroxyl protons by the radicals formed during polymer degradation.

Journal of Composites Science doi: 10.3390/jcs10100547

Authors: Liang Chang Qinghua Song Tiancheng Zhao Yuzhe Guo Yuxin Wei Chao Gu

Existing learning-based AFP inspection methods predominantly rely on grayscale/depth-like representations or directly learned appearance features, while the directional relationship between laser-profile height variation and defect boundaries remains insufficiently exploited. This limitation is particularly relevant to low-contrast and slender AFP defects, for which periodic tow textures can interfere with boundary localization and only limited real defect samples are typically available. To address these issues, this study develops an AFP-specific instance-segmentation framework that coordinates geometry-informed input representation, deformation-aware feature processing, and training-distribution expansion. After outlier correction, RANSAC reference-surface fitting, and residual enhancement, the residual height field and its signed horizontal and vertical gradients are used as a three-channel input to explicitly represent local surface amplitude and directional boundary variation. C2f_DCNv2 and CBAM are incorporated into YOLOv8n-Seg for complementary purposes: adaptive sampling along elongated or irregular defect geometry and suppression of less relevant tow-texture responses, respectively. ConSinGAN-generated samples are screened, manually annotated, and used only for training to expand the represented defect morphology. Three-seed experiments show that the gradient-enhanced representation improves mask P, mask R, mask mAP@50, and mask mAP@50:95 by 2.56, 1.67, 2.85, and 1.22 percentage points over the depth-enhanced input. The architecture modification provides additional gains of 1.32 and 1.52 points in mAP@50 and mAP@50:95, and ConSinGAN augmentation adds 1.19 and 1.51 points. The complete method achieves 94.36% mask P, 91.93% mask R, 94.71% mask mAP@50, and 60.17% mask mAP@50:95. The complete post-acquisition dual-window processing pipeline requires 26.8 ± 0.9 ms per synchronized pair, compared with a 409.6 ms acquisition interval at 30 m/min. These results demonstrate the effectiveness of coordinating AFP-specific geometric representation, morphology-adaptive feature processing, and controlled training-set expansion for online defect segmentation under the evaluated conditions.

Journal of Composites Science doi: 10.3390/jcs10100546

Authors: Junmin Zhu Yang Li Yunfei Xia Zhenwei Zhang Mingyang Jin Guoliang Dai

To ensure the performance of reclaimed asphalt binder in reclaimed asphalt pavement, this paper investigates the feasibility of using castor oil, a vegetable oil, to rejuvenate aged asphalt. The influence of castor oil on the performance of aged asphalt was evaluated through a series of tests. The results indicate that the safety of asphalt rejuvenated with castor oil meets specification requirements. Based on the findings from three key metrics, the effectiveness of the rejuvenated asphalt can be nearly returned to that of the original asphalt. Asphalt rheological testing results indicate that as the bio-oil content increases, both the high- and low-temperature characteristics of the rejuvenated asphalt progressively improve. Consequently, castor oil presents considerable potential for application as a rejuvenator in the realm of aged asphalt.

Journal of Composites Science doi: 10.3390/jcs10100545

Authors: Marina Kuchevskaia Oleg Morozov Anastasia Kondrateva Vladimir Terekhov Ekaterina Kudriashova Alexey Fedorov Tatiana Apukhtina Ekaterina Afanaseva

The application of high-temperature bismaleimide resins in structural composites is inherently limited by the trade-off between thermal performance and processability. Here, we report a targeted molecular design strategy to overcome this operational bottleneck. By introducing bulky ortho-ethyl substituents into a monomeric architecture, premature homopolymerization was selectively suppressed up to 300 °C while maintaining the rigidity of the aromatic backbone. The resulting resin system provides an optimized processing profile for vacuum-assisted resin transfer molding (VARTM), characterized by low melt viscosity (<400 mPa·s) across a 120–140 °C range and isothermal stability exceeding 8 h. The fabricated carbon fiber reinforced polymer (CFRP) exhibits a high glass transition temperature (up to 277 °C) and retains 92.5% of its room-temperature flexural modulus at 250 °C (49 GPa). This strategy serves as a technological basis for the autoclave-free manufacturing of heat-resistant structural materials.

Journal of Composites Science doi: 10.3390/jcs10100544

Authors: A. Lemartinel M. Castro J. F. Feller

The incorporation of composite materials in structural applications is experiencing significant growth, with structures such as composite wind turbine blades now reaching 100 m in length and operating under increasingly demanding environmental conditions, including broad temperature ranges. Reliable structural health monitoring (SHM) based on quantum piezoresistive strain sensors (sQRS) therefore requires a thorough understanding of how temperature affects the sensor’s response. In this study, we investigate the effect of temperature, from 25 °C to 150 °C, on the electrical and piezoresistive behaviour of epoxy-based carbon nanotube (CNT) sensors intended for integration into composite structures. We show that below the glass transition temperature (Tg ≈ 95–100 °C, determined by dynamic mechanical analysis) of the epoxy matrix, the sensor’s resistance decreases reversibly and near-instantaneously with temperature, governed by enhanced tunnelling conduction competing with matrix thermal expansion. Under mechanical loading, this thermal sensitivity translates into a marked, though still usable, decrease in gauge factor (56% between −30 °C and 80 °C), attributed to reduced stress transfer and increasing matrix Poisson’s ratio. Above Tg, the sensor’s response becomes irreversible: matrix softening enables dynamic percolation and permanent reorganisation of the CNT network, leading to a substantial, non-recoverable loss of piezoresistive sensitivity. These findings identify Tg as the practical operational limit for reliable strain sensing with sQRS, and demonstrate that below this limit, temperature-induced resistance drift is linear and readily compensated, making the sensor’s thermal response itself a potential tool for in situ detection of the matrix’s physical state.

Journal of Composites Science doi: 10.3390/jcs10100543

Authors: Almat Sagitov Karibek Sherov Dinara Kossatbekova Ainur Turusbekova Javokhir Toshov Saule Mendaliyeva Medgat Mussayev Saule Ainabekova Gulziya Sherova Bauyrzhan Zhumagaliyev

This study investigates the effect of extrusion temperature and print layer thickness on the thermal conditions for interlayer bond formation during FDM printing of ABS plastic. Computer simulations were performed using SOLIDWORKS 2024® with transient thermal analysis. Two print layer thicknesses were considered: 0.10 and 0.25 mm, and three temperatures for the newly deposited layer: 220, 240, and 260 °C. The glass transition temperature of ABS, taken as 105 °C, was used as the criterion for evaluating the thermal state of the interlayer zone. The simulation results showed that increasing the temperature of the newly applied layer increases the depth of the zone with a temperature of Tg ≥ 105 °C and the duration for which the temperature at the interlayer interface remains above the glass transition temperature. For a layer thickness of 0.10 mm, the maximum depth of this zone increased from 0.08 mm at 220 °C to 0.14 mm at 260 °C. For a layer thickness of 0.25 mm, the maximum depth increased from 0.24 to 0.37 mm. Tensile tests were conducted on ABS specimens with layer thicknesses of 0.10 and 0.25 mm to experimentally verify these findings. The experimental tests showed that increasing the thickness of the printed layer from 0.10 to 0.25 mm results in an 8.7% increase in the average maximum tensile stress of ABS plastic and an increase in the calculated relative strain. The experimental results are consistent with trends observed in thermal modeling and show that increasing printed layer thickness leads to deeper, longer-lasting heating of the previously formed material and a higher maximum load withstood by the ABS samples.

Journal of Composites Science doi: 10.3390/jcs10100542

Authors: Abdallah M. Almomani Mohammed A. Almomani Muath A. Bani-Hani Mahmoud A. Hayajnh

Lightweight unmanned aerial vehicle (UAV) panels require electromagnetic interference (EMI) shielding with limited added mass and manageable manufacturing demands. This study compares seven experimentally reported thermoset carbon-fiber-reinforced polymer (CFRP) shielding configurations on a common X-band basis. The decision matrix combines paired mean shielding gain relative to each study’s matched pristine laminate, dry functional-modifier areal mass, and manufacturing and integration burden. TOPSIS and VIKOR were applied using reference weights of 0.40, 0.40, and 0.20. The polyaniline (PANI)-coated carbon-fabric CFRP containing 1 wt.% reduced graphene oxide/Fe3O4 hybrid (C4) ranked first by both methods, providing a 35.90 dB shielding gain at 13.26 g m−2 dry modifier mass. PANI-decorated ACF-7/CFRP (C3) ranked second under TOPSIS, while the two-veil MXene/PEDOT:PSS/APP-modified reclaimed-carbon-fiber CFRP (C6) ranked second under VIKOR. C4 ranked first in 18 of the 19 TOPSIS weight-sensitivity cases and in all 19 VIKOR cases. Across the 243 bounded-input cases, both methods also kept C4 at first place. Under the stated UAV panel priorities, C4 is the preferred balanced configuration, while C3 is the low-mass alternative and C6 the shielding-prioritized alternative. The framework provides a traceable screening route while retaining source-specific mechanical evidence outside the weighted score.

Journal of Composites Science doi: 10.3390/jcs10100541

Authors: Pavel Oskin Konstantin Egorov Daria Lavrova Nadezhda Dmitruk Irina Gutnik Sergey Alferov Tatiana Dyachkova Valery Alferov Olga Ponamoreva

Progress in the field of modern heterogeneous catalysts requires the development of composite materials with a well-developed surface area and sorption capacity, as well as the possibility of functionalization in a specific direction. This paper presents the results of electrochemical synthesis of composites based on an organosilica matrix and multi-walled carbon nanotubes for subsequent application as a platform for enzyme immobilization. By potentiostatic electrodeposition, composite coatings based on two types of organosilica sol (STPEG and STEG) were applied to the surface of a glassy carbon electrode with the addition of MWCNTs subjected to various methods of oxidative treatment. Optimization of the deposition time in the range of 0.5–5 min revealed that the maximum electrochemical activity and heterogeneous transfer rate constants were achieved at 1 min of electrodeposition. It has been found that the use of MWCNTs oxidized in H2O2 vapors provides the best balance between hydrophilicity, conductivity, and the formation of a permeable matrix due to fewer defects and carboxyl groups. It has been demonstrated that the selected OP-SG/1 composite effectively supports mediator bioelectrocatalysis with recombinant laccase ScaSL in the presence of an ABTS mediator, as evidenced by the formation of sigmoidal CVs of catalytic oxygen reduction. The obtained results confirm that the electrodeposited organosilica composite is a promising and biocompatible material for the development of surface biocatalysts, which can be used in wastewater treatment technologies and bioreactor design.

Journal of Composites Science doi: 10.3390/jcs10100540

Authors: Vinício Cecconello Ramoel Serafini Matheus Poletto

Poor fiber–matrix interfacial adhesion limits the mechanical performance of synthetic fiber-reinforced cementitious composites. To overcome this limitation, this study investigates the impact of surface-treating polypropylene (PP) macrofibers with graphene oxide (GO) on single-fiber pullout behavior. The thermal and structural response of the treated fibers was characterized using Differential Scanning Calorimetry (DSC), and mechanical performance within the cementitious matrix was quantified. DSC analyses revealed changes in the thermal response of the polymer surface caused by the coating. In pullout tests, surface modification with GO resulted in higher resistance values at specific displacement levels, fR0.5 and fR3.5, showing increases of 20% and 18%, respectively. It is concluded that the GO coating effectively acts as an interfacial anchoring agent, optimizing interfacial shear transfer and enhancing the composite’s energy dissipation capacity in cementitious structures.

Journal of Composites Science doi: 10.3390/jcs10100539

Authors: Siti Nurain Yusof Ahmad Hamdan Ariffin Tabrej Khan Tamer A. Sebaey

This study investigated the low-temperature thermal treatment of EVA encapsulant from an end-of-life 180 Wp monocrystalline PV panel while evaluating the preservation of recovered crystalline silicon. TGA showed that EVA underwent major decomposition between approximately 330 and 480 °C, with an onset temperature of 310.4 °C and mass loss of 94.34%. Thermal treatment was subsequently conducted at 300–500 °C for 30–50 min under nitrogen using a Taguchi L9 design. XRD analysis showed substantially improved silicon diffraction intensity after treatment, while the 300 °C residues were unsuitable for analysis due to incomplete EVA decomposition. Taguchi-based analysis was used as a preliminary screening approach to compare the investigated treatment conditions. Within the experimental range, 400 °C for 40 min was identified as a practical treatment condition based on the measured XRD response, treatment duration, and estimated furnace energy requirement. The results indicate that controlled thermal treatment promoted substantial EVA decomposition while maintaining detectable crystalline silicon in the treated material.

Journal of Composites Science doi: 10.3390/jcs10100538

Authors: Li-Tung Chang Aleksandra Drizo Meng-Tsun Lai Motamid Shaikh Yesong Gu Muhammad Omar Shaikh

Conventional seedling substrates such as rockwool and peat raise environmental concerns associated with disposal and resource extraction. Here, we investigate nanoclay–agarose hydrogels as candidate sustainable and biodegradable alternatives for seed germination and early plant growth under greenhouse conditions. Agarose hydrogels incorporating sodium bentonite nanoclay (NC) or activated carbon (AC) were prepared and evaluated for their structural, thermal, and biological performance using Brassica rapa (bok choy) as a model crop. Structural and physicochemical analyses revealed lamellar architectures, spectral features consistent with agarose–filler interactions, and composition-dependent thermal decomposition profiles. Dried NC hydrogels exhibited more open structures than the comparatively compact AC hydrogels. After 15 days under greenhouse conditions, NC40 (40 wt% nanoclay relative to agarose) achieved 100% germination and the highest mean fresh and dry biomass among the substrates compared for biomass, including rockwool and peat pellets. Over 42 days of soil burial, pure agarose and AC hydrogels showed more extensive visible breakdown consistent with biodegradation of the agarose matrix, whereas NC hydrogels retained their structural form for longer. These findings highlight nanoclay–agarose hydrogels as biodegradable, eco-engineered substrates with the potential to replace conventional growing media and advance sustainable agriculture.

Journal of Composites Science doi: 10.3390/jcs10100537

Authors: Mehrab Hasan Carter Thomas Yingtao Liu

Shape memory epoxy composites recover a programmed shape when Joule heating drives the matrix through its glass transition, and a key challenge for these smart materials is predicting the recovery angle at drive currents outside the tested range. In this work, three models were compared for this task: a Kohlrausch–Williams–Watts (KWW) theory based Physics-KWW constitutive model, a gradient-boosted tree model (XGBoost) using thermomechanical state features, and a support vector regression (SVR) model using raw experimental variables together with thermomechanical features. All models were assessed by a leave-one-current-out cross-validation method over nine current levels from 1.50 to 3.50 A. The physics-informed models generalized well to unseen currents, with the Physics-KWW model and XGBoost achieving R2 values of 0.911 and 0.915, respectively, compared with 0.841 for the SVR model under the same tuning protocol. Shapley analysis of a representative XGBoost fold identifies accumulated activation and estimated temperature as the dominant predictors. The results demonstrate comparable accuracy for the two physics-informed approaches, while their advantages remain conditional on the tested pipelines and calibration assumptions.

Journal of Composites Science doi: 10.3390/jcs10100536

Authors: Balamurali Kanagaraj Aman Kumar Nammalvar Anand Daniel Paul Thanaraj

This study experimentally investigates the residual performance of geopolymer-based slurry-infiltrated fibrous concrete (SIFCON) incorporating multi-walled carbon nanotubes (MWCNT) after exposure to elevated temperatures. Two SIFCON mixtures were examined: a reference geopolymer-based SIFCON (G-SIFCON) and an MWCNT-modified mixture (NM-G-SIFCON) containing 0.12% MWCNT by mass of the precursor materials. A total of five exposure conditions were considered, including the unheated condition and exposure for 30, 60, 90, and 120 min in accordance with the ISO 834 standard fire curve, corresponding to nominal furnace temperatures of approximately 821, 925, 986, and 1029 °C, respectively. The specimens were evaluated in terms of density, water-related change in mass, thermal change in mass, and residual compressive strength. The corrected mass-loss results showed an exposure-duration-dependent response, with NM-G-SIFCON exhibiting lower change in mass than G-SIFCON at 30, 60, and 120 min, but slightly greater change in mass at 90 min. The unheated compressive strengths of G-SIFCON and NM-G-SIFCON were 93 and 97 MPa, respectively. Following 120 min of fire exposure, the residual compressive strengths decreased to 23.7 MPa for G-SIFCON and 49.13 MPa for NM-G-SIFCON, corresponding to strength retention of 25.5% and 50.6%, respectively. The results demonstrate that MWCNT incorporation does not produce a uniform improvement in mass stability at all exposure durations; however, the NM-G-SIFCON mixture exhibited greater residual compressive-strength retention at prolonged fire exposure. The findings highlight the potential of MWCNT-modified geopolymer SIFCON for improving post-fire compressive performance, while further investigation of microstructural and tensile/flexural responses is required to establish the underlying mechanisms.

Journal of Composites Science doi: 10.3390/jcs10100535

Authors: Hamza M. Salman Shatha D. Mohammed Teghreed H. Ibrahim Rafaa M. Abbas Abbas A. Allawi

This study presents a theoretical investigation of encased composite columns under biaxial loading. The EUROCODE 4 theoretical model for generating the uniaxial interaction diagram was developed and used to meet biaxial requirements. The primary objective was to evaluate how internal steel ratios and configurations and concrete compressive strength influence the axial and biaxial flexural performance of the composite column. Ten models were analyzed, and the results were validated against previous experimental and analytical data. The results indicate that internal reinforcement is the primary driver of stiffness. Changing from an I-section to equivalent reinforcing bars or four steel angles significantly improves the y-axis stiffness. In addition, changes in concrete strength have a negligible effect on stiffness. Increasing concrete strength from 35 to 70 MPa only slightly changes the stiffness. A direct relationship between concrete strength and buckling resistance is observed. The interior steel configuration also shows that the distribution of steel within the column section modifies buckling resistance; therefore, no major reduction in the second moment of inertia is observed in any direction. Regarding flexural resistance, models with internal steel (steel sections or bars) placed at the column corners consistently outperform models with centralized sections. Symmetrical models provide uniform flexural strength across all angles of inclination of the neutral axis (0 to 90), unlike unsymmetrical models, which exhibit a weak axis and reduced flexural resistance. Finally, using steel angles at the column corners represents the most versatile model.

Journal of Composites Science doi: 10.3390/jcs10100534

Authors: Bin Yu Haifeng Zhao

Open-hole features are widely used in composite structures but inevitably alter intrinsic load-bearing behavior and fracture characteristics. This study develops an artificial intelligence-based method for surface damage morphology prediction of multi-hole carbon fiber reinforcement thermoplastic laminates. A pix2pix conditional generative adversarial network incorporating a rule-based ideal fracture mask is established to predict geometry-dependent fracture morphologies and evaluate its predictive capability for unseen geometric configurations. Four global pixel-based and five morphology-specific metrics are employed to assess the agreement between predicted and experimental damage morphologies. The results show that the proposed network successfully reproduces the dominant crack paths, critical-hole locations, and distributed surface-splitting patterns observed experimentally. Ablation analysis further confirms that ideal fracture mask provides effective guidance for fracture morphology prediction. Despite the limited training dataset, the model retains reliable predictive capability for unseen regions of the geometric parameter space and accurately identifies critical failure holes. Quantitative comparison of single-hole laminates further shows similar fracture characteristics under quasi-static and fatigue loading, indicating potential extension to fatigue applications. However, broader applicability requires validation using datasets with multi-hole fatigue specimens. Overall, the proposed method provides an image-based framework for predicting surface damage morphology under quasi-static loading and localizing fracture-critical regions within the predicted morphology.

Journal of Composites Science doi: 10.3390/jcs10100533

Authors: Zhenwen Gong Pengfei Ma

Buckling-restrained braces (BRBs) and viscous fluid dampers (FVDs) dissipate seismic energy through yielding hysteresis and velocity-dependent action, respectively. This paper takes a six-story reinforced concrete (RC) frame as the object, compares the seismic mitigation performance of the two types of devices under a common layout, and further investigates the structural responses of different layouts under near-fault ground motions. Wen-type BRB and Maxwell-type FVD models are established in ETABS 22 and verified against theoretical and published experimental results. The baseline analysis uses six horizontal components from three sets of ground motions (W1–W6), scaled to frequent (0.055 g), design-basis (0.15 g), and rare (0.31 g) earthquake levels, respectively, and direct-integration nonlinear time-history analyses are performed. Compared with the frame without dampers, the BRB model M2 and the FVD model M3 reduce the maximum inter-story drift ratio at all three levels. The reductions under frequent earthquakes are 36.7–42.7% and 41.9–54.6%, respectively; under design-basis earthquakes, 12.3–45.8% and 18.8–20.0%, respectively; and under rare earthquakes, 21.4–39.9% and 11.2–26.2%, respectively. Among the analyzed cases, M3 is more favorable for floor-displacement control under frequent and design-basis earthquakes, while M2 performs better in controlling the maximum inter-story drift ratio under rare earthquakes. The average additional damping ratios of the two models under the three earthquake levels are 1.33%, 1.98%, and 3.10% and 3.90%, 3.28%, and 2.30%, respectively. On this basis, two BRB and two FVD candidate layouts are established, each with 48 devices. Four sets of near-fault ground motion records with identified pulse azimuths are selected, and the horizontal components in the pulse azimuth and its orthogonal direction (W7–W14) are used for analysis. Under rare earthquakes, the inter-story drift ratio-oriented B–D scheme reduces the mean maximum inter-story drift ratio by 2.83% compared with the story shear-oriented B–S scheme; the inter-story relative velocity-oriented F–V scheme reduces it by 3.77% compared with the floor absolute acceleration-oriented F–A scheme. The differences in the mean peak roof absolute acceleration between the two groups of candidate schemes are both less than 0.5%. The results provide a reference for selecting candidate layouts by combining control objectives and device working characteristics.

Journal of Composites Science doi: 10.3390/jcs10100532

Authors: Akira Miyoshi Takumi Sekino Yutong Li Jun Koyanagi

This study presents a framework for estimating the longitudinal compression–compression fatigue life of unidirectional carbon-fiber-reinforced polymer (UD-CFRP) by linking entropy-based matrix degradation to a fiber micro-buckling criterion. A reference effective fiber-direction shear modulus of 2000 MPa was selected using published shear responses of carbon/epoxy composites. Its degradation was prescribed phenomenologically using Geff(Sv)=Gref(1−Dv), motivated by the viscous-damage stiffness-reduction factor in the nonlinear viscoelastic matrix model. The resulting entropy-dependent modulus was introduced into the micro-buckling equation to obtain residual compressive strength. The corresponding applied compressive stresses were determined from periodic unit-cell compression analyses; no periodic unit-cell shear analyses were used to identify the modulus. Viscous-entropy accumulation was estimated from single-element tension–compression simulations and extrapolated using a stated phenomenological high-cycle law. Fatigue life was defined by the intersection of applied compressive stress and residual compressive strength. The predicted S–N relationship was compared qualitatively with published longitudinal flexural-fatigue data at 25 °C and 2 Hz. Because the loading modes differ and the reference shear modulus comes from related, rather than identical, material systems, the comparison does not constitute direct experimental validation of compression–compression fatigue life.

Journal of Composites Science doi: 10.3390/jcs10100531

Authors: Yuzhe Guo Qinghua Song Liang Chang Tiancheng Zhao Shuaihui Zhu

Automated fiber placement (AFP) of advanced polymer composites requires timely monitoring of process conditions that influence gaps, overlaps, wrinkles, and inter-ply bonding. This study develops an end–edge–cloud decision-support framework that links read-only sensing, low-latency prediction, risk grading, operator confirmation, and traceable cloud optimization while retaining the numerical-control hard-interlock chain. The edge uses 18 temporal-statistical features for anomaly classification (TF-MLP-C) and temperature–pressure forecasting (TF-MLP-TP), while a separate nine-feature Cutter-RUL MLP estimates cutter life. In 90 days of single-machine operation, the pipeline processed 2.87 × 108 records at 36.9 records/s, supported 80 concurrent users, and achieved 99.6% availability. On fixed-seed parametric simulations, classification accuracy and macro F1 were 91.67% and 90.28%, respectively; mean warning lead time was 5.83 ± 2.54 s. The temperature and pressure MAEs were 0.713 °C and 26.96 N, and cutter-life MAE was 139.52 cuts (R2 = 0.9819). The 90-day field records establish pipeline operation and operator-facing logging, not independent predictive-model accuracy; all reported model scores are simulation-based proof-of-concept estimates, with no evaluation on a held-out labeled AFP production test set. The contribution is a deployable and auditable monitoring workflow that turns heterogeneous AFP data into bounded decision support and provides a reproducible basis for future multi-machine and quality-linked validation.

Journal of Composites Science doi: 10.3390/jcs10100530

Authors: Tiancheng Zhao Qinghua Song Liang Chang Yuzhe Guo Yu Zhang

Automated Fiber Placement (AFP) of carbon-fiber composite materials constitutes a core digital manufacturing technology for large-scale aerospace composite components with double-curved surfaces. Gap and overlap defects induced during path planning degrade the fatigue performance of composite parts and threaten aircraft structural safety. Aiming at the limitation that conventional post-forming non-destructive testing cannot predict lay-up defects at the design stage, this work analyzes the generation mechanisms of gaps and overlaps from differential-geometric constraints of non-developable surfaces. A defect classification framework and geometric identification method oriented to the path-planning phase are established. According to geometric formation causes, lay-up defects are categorized into boundary overlap–gaps induced by tow-cutting operations and internal gaps originating from trajectory divergence over curved surfaces. Twenty boundary working conditions are defined for triangular boundary defects, and internal gaps are further subdivided into tape-type gaps and rectangular gaps. A triangular-patch approximation algorithm is adopted to compute the area of gap–overlap regions and quantitatively evaluate lay-up coverage. The simulation results reveal an inherent trade-off between allowable fiber-angle deviation and lay-up coverage on double-curved mold surfaces.

Journal of Composites Science doi: 10.3390/jcs10100529

Authors: Gagik Ayvazyan Surik Khudaverdyan Laura Lakhoyan Alina Semchenko Ashok Vaseashta

We performed a comparative study of ZnO films synthesized by the sol–gel method on planar silicon surface (ZnO/Si) and on nanostructured black silicon layer (ZnO/b-Si) formed by reactive ion etching. The influence of b-Si on ZnO morphology, composition, and optical, wetting, photoelectric, and gas-sensing properties was investigated. The ZnO/b-Si hybrid composite exhibits significantly higher optical absorption in the 350–1100 nm range and a lower contact angle (36° vs. 59°) than ZnO/Si. The current–voltage characteristics show an increase in the n-ZnO/p-Si heterojunction current when b-Si is used as an interlayer, under both forward and reverse bias. Under illumination at 370 nm, the photocurrent of both samples increases, with a stronger photoresponse for ZnO/b-Si. The spectral responsivity in the 350–1000 nm range exhibits maxima near 370 and 860 nm. Cyclic transient measurements confirm the reproducibility of the photoresponse and a higher absolute photocurrent for ZnO/b-Si. Gas-sensing measurements showed that ZnO/b-Si exhibits a higher response to NO2 than ZnO/Si over the entire studied temperature (125–250 °C) and concentration (10–100 ppm) ranges. These results demonstrate that combining a nanostructured b-Si layer with a ZnO film can effectively tailor the optoelectronic and gas-sensing properties of this hybrid composite.

Journal of Composites Science doi: 10.3390/jcs10100528

Authors: Mohamadreza Delzendeh Omar Chaallal

The performance of steel elements retrofitted with carbon fiber-reinforced polymer (CFRP) relies on the bond behavior of the interface between CFRP and steel substrate, as the adhesive is typically the weakest link of the retrofitting system. Therefore, understanding the bond behavior between CFRP and steel substrate is crucial for retrofitting design of steel structures. This necessity has been the main impetus for conducting the present experimental study on the bond behavior of CFRP/steel double strap joints under static loadings. To that end, the adhesive type, CFRP-bonded length, and surface preparation are the parameters considered in this research. Additionally, the effect of CFRP elastic modulus on the bond behavior is examined by using Normal Modulus (NM) and Ultra-High Modulus (UHM) CFRP with approximately the same tensile capacity. Failure modes, bond strength, effective bond length, and bond–slip curves are some of the key issues that will be thoroughly discussed in this study.

Journal of Composites Science doi: 10.3390/jcs10100527

Authors: Ashtar S. Al-Luhybi Alireza Bahrami Diyar N. Qader Taghreed Khaleefa Mohammed Ali

Cement mortar is a widely used construction material for structural and nonstructural applications. Since mortar consumes large amounts of cement, replacing part of it with waste materials can improve sustainability. Waste cardboard can be burned and ground into a material suitable for partial cement replacement, while waste plastic fibers from tube-cutting processes can be utilized to reinforce cement mortar. In this study, cardboard powder ash (CPA) and tiny PVC plastic fiber (TPF) were incorporated in cement mortar by different amounts. The CPA replacement ratios were 0, 2.5, 5, and 7.5% by weight of cement, while the TPF contents were 0.25, 0.50, and 0.75% by volume of the mortar mix. The results showed that incorporating CPA and TPF reduced workability and compressive strength, while improving flexural strength and water absorption. A slight decrease in ultrasonic pulse velocity (UPV) was observed, although all mixtures remained within the good-quality mortar range. The optimum amounts of CPA and TPF were 5% and 0.25%, respectively, yielding a mortar with a compressive strength of 44.12 MPa, a flexural strength of 10.16 MPa, a UPV of 4.03 km/s, and a water absorption ratio of 4.21%. Furthermore, response surface methodology (RSM) combined with desirability function analysis was employed to simultaneously optimize all six responses. The RSM-based multi-objective optimization identified an optimal mix composition of 3.82% CPA and 0.36% TPF, demonstrating predicted values of 45.37 MPa for compressive strength at 56 days and 4.05 km/s for UPV at 56 days, with an overall desirability response of 0.663, confirming that RSM is an effective and practical tool for optimizing sustainable cement mortar formulations.

Journal of Composites Science doi: 10.3390/jcs10100526

Authors: James Ghilotti Paula Gabaldón-Moya Ángel Vicente-Escuder José Luis Sanz Carmen Llena María Melo

The bonding performance of restorative composites to Biodentine™ XP remains insufficiently characterised, particularly regarding the influence of adhesive strategies on mechanical behaviour and fracture characteristics. This in vitro study evaluated the shear bond strength between Biodentine™ XP and a flowable bulk-fill composite using four restorative protocols: acid etching with Prime&Bond® NT (G1), acid etching with Scotchbond™ Universal (G2), Scotchbond™ Universal without prior acid etching (G3), and no adhesive treatment (G4). Cylindrical specimens measuring 4.7 mm in diameter and 7 mm in total height were prepared, comprising 3 mm of Biodentine™ XP and 4 mm of composite. Uncured composite was placed directly onto the Biodentine™ XP surface and light-cured in situ following one of four bonding protocols. Specimens were stored for 72 h at 37 °C and 100% relative humidity before shear bond strength testing. Fracture patterns were assessed by optical microscopy, and representative surfaces were characterised using scanning electron microscopy and energy-dispersive X-ray spectroscopy. Significant differences in bond strength were detected among groups (p = 0.002), with G4 showing significantly lower values than G1 and G2. No significant differences were observed among the adhesive-treated groups. Fracture-pattern distribution also differed significantly (p < 0.001); acid-etched groups showed no adhesive failures, whereas adhesive failures occurred in G3 and were most frequent in G4. SEM-EDS revealed morphological and elemental differences among the selected fractured regions. Within the limitations of this short-term in vitro study, adhesive treatment improved bonding between Biodentine™ XP and the bulk-fill composite. Phosphoric acid etching did not significantly increase bond strength among adhesive-treated groups but was associated with a different failure-mode distribution. The mechanisms underlying these findings require direct chemical and long-term interfacial investigation.

Journal of Composites Science doi: 10.3390/jcs10100525

Authors: Hana Fatih Abdulla Bestoon Mohammed Faraj

Background: Post-curing may influence the properties of 3D-printed ceramic-filled resin restorations. This study compared four post-curing protocols for adaptation and microtensile bond strength (µTBS) of cemented, thermocycled DLP-printed inlays. Methods: Seventy-six maxillary premolars with standardised MOD cavities received inlays randomised (n = 19) to standard post-curing in air (SP), glycerine-immersed post-curing (GP), or SP plus microwave heating in glycerine (MG; 800 W nominal, 50 s) or autoclaving (AT; 121 °C). After cementation and 5000 thermocycles, adaptation discrepancy—a composite of post-curing change, seating, cement layer and ageing—was measured at 11 points by triple-scan superimposition before µTBS testing of the inlay–cement–dentine complex and failure-mode analysis. Results: Discrepancy (F(3, 37.6) = 24.47, p < 0.001) and µTBS (F(3, 39.8) = 6.09, p = 0.002) differed among protocols. MG showed the largest discrepancy (104.42 ± 13.57 µm; p < 0.01 versus all groups), lower µTBS than GP and SP (15.04 ± 5.13 versus 21.58 ± 4.35 and 20.19 ± 5.33 MPa) and predominantly adhesive failures (68.4% of teeth; interface unidentified). GP had the numerically lowest discrepancy (77.09 ± 5.48 µm), but its 7.7 µm difference from SP was within measurement uncertainty and not robust to sensitivity analysis. AT did not differ from SP. Conclusions: The complete MG protocol was associated with greater discrepancy and lower µTBS; GP did not differ robustly from SP.

Journal of Composites Science doi: 10.3390/jcs10100524

Authors: Rajesh Murkur Dharmalingam Ganesan Balaji Kuppusamy

Natural-fiber-based composite materials are gaining popularity because they are lightweight, renewable, and more sustainable than existing synthetic fiber composites, offering numerous benefits for structural engineering applications. However, the lack of adhesion at natural-fiber–matrix interfaces due to the non-polar hydrophobic nature of the fibers and hydrophobic epoxy matrices produces gaps due to void formation during manufacturing. Also, the non-uniform distribution of natural fibers and the reinforcement make the composite perform inefficiently, prone to brittleness, have lower temperature resistance and lack proper bonding between fibers. The present research work aimed to achieve the maximum flexural, tensile, compressive strength, thermal resistance and toughness of areca–hemp hybrid epoxy composites with nano-silica (AHNS) at varying percentages (1 wt%, 2 wt%, 3 wt%, and 4 wt%) as reinforcement. The results showed that AHNS-2 with 2 wt% of nano-silica yielded superior flexural and compression strength and Shore-D hardness (64.40 N/mm2, 57.46 N/mm2 and 83, respectively); AHNS-4 with 4 wt% nano-silica exhibited the best performance in terms of tensile strength, toughness and maximum degradation-rate temperature (61.90 N/mm2, 81.99 J/m and 377.4 °C, respectively). The SEM morphology analysis revealed fiber pull-out, matrix cracks, fiber breakage, and fiber–matrix interfacial characteristics. These microstructural features showed a considerable impact on the mechanical properties of the composites, especially on density, hardness, strength and toughness. The elemental analysis revealed that carbon (64.92%) and oxygen (33.08%) were the predominant elements present, although silicon (2%) was also present in AHNS-2. The presence of silicon provided evidence of the localized incorporation of nano-silica within the epoxy matrix. It was observed that the mechanical properties of AHNS with 1–4 wt% nano-silica were significantly better compared to the unfilled composite (AHNS-0 wt% nano-silica).

Journal of Composites Science doi: 10.3390/jcs10100523

Authors: Ghasan Fahim Huseien Abhimanyu Goel Akram M. Mhaya Iman Faridmehr Waiching Tang

Geopolymer materials have attracted considerable interest due to their economic, engineering, and environmental advantages. As global industrialization intensifies and infrastructure demands increase, the need for sustainable and alternative construction materials has become more urgent. Despite the considerable potential of Bottle Glass Powder (WBGP) incorporating Ground Blast Furnace Slag (GBFS)-based geopolymer materials, further research is required to improve their mechanical properties, reduce porosity, and enhance their resistance to elevated temperatures through effective modification of the binder system. In response to this challenge, the present study aims to develop high-performance geopolymer mortars by incorporating silica fume (SF) as a partial replacement for GBFS, with the goal of improving the performance of WBGP-based geopolymer systems. These were activated using a low-molarity sodium hydroxide solution in combination with sodium silicate and subsequently cured at ambient temperature. The influence of varying SF content on the mechanical, physical, and microstructural characteristics of WBGP-based geopolymer was evaluated using flexural, compressive, and tensile strength measurements, along with advanced analytical techniques, including XRD and FTIR. Furthermore, the durability characteristics of the developed geopolymer, including porosity and resistance to elevated temperatures (800 °C), were evaluated. The findings indicated that incorporating 3% and 6% SF as a replacement for GBFS enhanced strength performance. At the optimal mix containing 6% SF, the reported results showed enhanced bond strength between binder components, yielding a compressive strength of 36.2 MPa after 56 days, compared with 29 MPa for the control specimen. The substitution of GBFS by 6% of SF substantially reduces the geopolymer porosity and increases its resistance to elevated temperatures. These results offer valuable guidance for incorporating SF into the design and formulation of WBGP-GBFS geopolymer mortars, adding to the progression of sustainable and high-performance construction materials.

Journal of Composites Science doi: 10.3390/jcs10100522

Authors: Pavol Mikuš Oleh Pastukh Andrii Buketov Yuriy Petrov Oleh Totosko Danylo Stukhliak Vitaliy Sotsenko Igor Gritsuk Alena Breznická Maroš Eckert

This paper presents the results of an investigation into the feasibility of applying ensemble machine learning algorithms to predict the mechanical properties of nanofilled epoxy composites, aimed at enhancing the reliability of water transport facilities. The study is positioned as a validated proof-of-concept demonstrating the applicability of ensemble ML models for property prediction tasks in epoxy composites, rather than as the formulation of a universal predictive framework. The primary objective of this study is to develop an efficient tool for predicting the mechanical performance of nanofilled epoxy composites based on ensemble machine learning paradigms to improve the operational reliability of marine and watercraft components. Utilizing experimental data on the properties of composites formulated from DER-331 epoxy resin with varying loadings of multi-walled carbon nanotubes (0–0.125 wt.%), seven ensemble models were developed employing Decision Trees, Random Forest, Gradient Boosting, AdaBoost, Bagging, Stacking, and Voting algorithms. It was established that the AdaBoost algorithm provides the highest predictive accuracy (MAPE = 8.02%). Linear statistical tests (Pearson correlation and one-way F-test) identified a statistically significant influence only for adhesive bond strength (solidity), whereas mutual information analysis unveiled pronounced non-linear dependencies for filler loading (filler), residual stresses (residual stresses), and heat resistance (heat resistance). Adhesive strength (mean importance of 0.47; Consistency Score of 81.37%) and residual stresses (Consistency Score of 85.17%) were identified as the most consistent and critical factors across the evaluated models. In contrast, filler loading exhibited the lowest inter-model consensus (Consistency Score = −20.59%), directly reflecting the complex, non-linear nature of its reinforcing mechanism. It is proven that the implementation of ensemble machine learning algorithms coupled with subsequent feature importance analysis offers an effective framework for predicting the mechanical properties of epoxy composites, enabling a substantial reduction in the required volume of routine experimental testing. The obtained results establish a solid foundation for developing durability prediction methodologies for protective coatings utilized in water transport and can be directly applied to optimize composite formulations with tailored, predictable operational properties.

Journal of Composites Science doi: 10.3390/jcs10100521

Authors: Francis M. G. Ramírez Luiz G. M. Lise Fabian Nowacki Marcelo F. S. F. de Moura Raul D. F. Moreira Joachim Hausmann

Developing reliable numerical tools and analytical methodologies is essential to optimize the design phase of composite structures. The quasi-static fracture behaviour of glass-fibre reinforced polymer bonded joints was evaluated for bidirectional and quasi-isotropic sequences. The specimens were bonded with a two-component epoxy-based adhesive system. The complete mixed-mode I+II fracture envelope was obtained using double cantilever beam, three-point bending End-Notched Flexure, and mixed-mode bending configurations. A data reduction scheme based on the equivalent crack method was adapted to calculate fracture energies as a function of the compliance evolution recorded during the tests. The power law energy fracture criterion was used to describe the complete mixed-mode I+II fracture envelope. The criterion proved to be very accurate in predicting the mixed-mode fracture behaviour for both series. A cohesive zone model with a trapezoidal softening law was used to validate the experimental procedure of the three test configurations. The results obtained for the fracture envelope using the power law criterion and the local strengths were used as input for the numerical simulations. The model efficiently described the full fracture envelope of both stacking sequences, with a deviations below 3% for the B series and below 7.5% for the Q series.

Journal of Composites Science doi: 10.3390/jcs10100520

Authors: Alexandr V. Marchuk

Two variants of a semi-analytical finite element method are proposed for solving complex three-dimensional elasticity problems of laminated plates subjected to longitudinal-transverse bending under localized loading. The first variant employs a plate model that accounts for transverse shear and thickness compression. Its distinctive feature is that the unknown functions are defined on the outer surfaces of the layers, which makes it possible to subdivide individual layers into sublayers and thereby improve the accuracy of the numerical results. In contrast, conventional plate models accounting for shear and thickness compression generally use a single reference surface, which makes layer subdivision difficult to implement. In the second variant, the through-thickness distributions of the unknown functions are determined by an exact solution of the corresponding system of differential equations. In both variants, the finite element method is used for approximation along the (x)-axis, whereas trigonometric functions are employed for approximation along the (y)-axis. The development of two independent approaches is motivated by the sensitivity of the considered problems to approximation and numerical errors, which becomes particularly pronounced for layered plates subjected to localized longitudinal-transverse bending when the applied longitudinal load approaches its critical value. The agreement between the results obtained using the two variants provides an independent verification of the proposed approaches. Numerical analyses of the behavior of layered plates under localized longitudinal-transverse bending were performed. The results demonstrate that, for the class of problems considered, polynomial approximation of the unknown functions through the thickness of a layer represented by a single sublayer may produce significant errors, particularly when the longitudinal load is close to its critical value.

Journal of Composites Science doi: 10.3390/jcs10100519

Authors: Victricia Aku Turkson Eliana Díaz-Cruces Cristina de-la-Macorra-García Jorge Troconis Oscar Casanova-Carvajal Stephanie Marina Díaz-López Juan José-Uriarte Joan Manuel Rodríguez-Díaz Frederico B. De Sousa Camilo Zamora-Ledezma

Breast cancer remains a highly heterogeneous disease, and conventional two-dimensional cell cultures and animal models do not fully reproduce the complexity of the human tumor microenvironment. More physiologically relevant in vitro platforms are therefore needed to improve disease modelling and preclinical therapeutic evaluation. In this review article, recent advances in three-dimensional (3D) bioprinting for breast cancer modelling, diagnosis, therapeutic testing, and clinical translation are discussed. A PRISMA ScR-guided search of Scopus was conducted for studies published between 2015 and July 2026, resulting in 74 selected sources. A complementary bibliometric analysis of 129 Scopus-indexed documents was also performed to identify publication trends and major research directions. The review also covers bioprinting techniques, bioink formulations, crosslinking strategies, and multicellular breast tumor models. Particular attention is given to extrusion-based approaches using alginate-, gelatin, collagen, fibrin, and composite-based bioinks, as well as light-based bioprinting strategies employing photocrosslinkable methacrylate bioinks, including but not limited to gelatin methacrylate (GelMA), collagen methacrylate (ColMA), and hyaluronic acid methacrylate (HAMA), decellularized extracellular matrix-based bioinks, as well as patient-derived, vascularized, and tumor-on-chip systems. Furthermore, it is demonstrated that 3D bioprinting provides improved control over tumor architecture, cell–matrix interactions, stromal organization, and therapeutic-response studies. Finally, standardization, regulation, governance, reproducibility, vascularization, immune integration, scalability, and clinical validation that remain as critical challenges for translation into precision oncology are discussed.

Journal of Composites Science doi: 10.3390/jcs10100518

Authors: Elza Briuka Ernests Kiops Dmitrijs Serdjuks Janis Sliseris Andris Berzins Arturs Zīverts Ulvis Skadins Janis Fabriciuss Vjaceslavs Lapkovskis

The present study investigates the shear behaviour of screw-glued and mechanical flange-to-web connections intended for cross-laminated timber (CLT) ribbed panels, with the aim of improving composite behaviour and enhancing the structural performance of long-span timber floor and roof systems. Fifteen CLT-glue laminated timber (GLT) specimens were divided into five groups. One group incorporated SHARP501200 (SHARP) serrated steel plates, while four groups used screw-glued connections manufactured with LOCTITE HB (HB) or LOCTITE HB XE (HB XE) polyurethane (PUR) adhesive used in CLT manufacturing. For the adhesive groups, the screws were installed either from the CLT-flange side or from the GLT-web side to evaluate the influence of the assembly configuration. The specimens were subjected to monotonic quasi-static loading, and the resulting load–slip and load–displacement relationships were evaluated in terms of peak resistance, initial stiffness, post-peak response, and failure mode. The mechanically connected specimens achieved an average maximum load of 39.57 kN, whereas the screw-glued groups ranged from 141.20 kN to 198.90 kN. Installing the screws from the GLT-web side increased the average load-bearing capacity. The screw-glued connections exhibited high initial stiffness and predominantly timber-related failure, while the mechanical connection showed lower resistance and a more gradual post-peak response. Nonlinear finite element models were developed in Verisim4D (V2026), in which the CLT–GLT interfaces were represented by cohesive-zone contact elements governed by a tri-linear shear stress–slip law, consistent with the shear-dominated (Mode II) failure mode observed experimentally for both joint types. The results obtained provide design-relevant parameters and modelling strategies for optimising CLT ribbed panel joints in ultimate and serviceability states, thereby contributing to the development of efficient and environmentally sustainable multi-storey timber structures.

Journal of Composites Science doi: 10.3390/jcs10100516

Authors: Qinghua Song Liang Chang Tiancheng Zhao Yuze Guo Jing Zhu

Automated fibre placement (AFP) is a key process for manufacturing advanced polymer–matrix composite aerostructures; however, an uneven compaction-pressure distribution of tows during lay-up reduces the inter-laminar bonding strength and induces processing defects such as bridging and wrinkles. In this study, a pressure regulation strategy coordinating simulation-based feed-forward planning with closed-loop feedback control is proposed as a modified processing route for improving the manufacturing quality of polymer composites. The strategy adopts a two-layer “planning–execution” architecture. In the planning layer, process parameters and placement trajectories are optimized in advance based on a compaction-roller pressure simulation model and a compaction-uniformity index. In the execution layer, closed-loop pressure control suppresses on-site disturbances in real time to ensure that the simulation objectives are realized, thereby achieving uniform control of the compaction-pressure field. Finally, multi-angle lay-up experiments were carried out on a convex-surface mould, and the pressure field was measured using pressure-sensitive films. The results show that the proposed regulation strategy improves pressure distribution uniformity by more than 6%, effectively enhancing curved-surface lay-up quality and the consolidation quality of advanced polymer composite components. This work provides an intelligent design-and-manufacturing route that links process simulation with real-time control for high-quality automated composite processing.

Journal of Composites Science doi: 10.3390/jcs10100517

Authors: Jéssica Salomão Lourenção Moacir Kripka Víctor Yepes Élcio Cassimiro Alves

Steel–concrete composite tubular columns have become increasingly attractive for sustainable structural applications due to their high load-carrying capacity and efficient material utilization. However, optimizing their structural performance while simultaneously minimizing embodied carbon emissions and material cost remains a challenging multi-objective problem. This study presents a comprehensive optimization framework for circular, rectangular, and square composite tubular columns composed of high-strength materials, and using the Particle Swarm Optimization (PSO) and Multi-Objective Particle Swarm Optimization (MOPSO) algorithms. The multi-objective optimization simultaneously maximizes axial load capacity while minimizing embodied CO2 emissions, considering both sections with (WR) and without (WoR) additional longitudinal reinforcement, enabling the identification of optimal trade-offs between structural performance and environmental impact. Design variables include the cross-sectional dimensions, concrete compressive strength, steel yield strength, and reinforcement configuration. The resulting Pareto-optimal solutions are further evaluated using a multi-criteria decision-making approach based on Minkowski Metrics combined with Entropy Theory to identify the best overall compromise solution. The numerical results demonstrate that the use of high-strength materials can reduce embodied CO2 emissions by up to 16% in the analyzed cases. The implemented load-bearing capacity formulation was also validated against experimental results, yielding a mean Nexp/NNBR16239 ratio of 1.01 for the six specimens analyzed. The multi-objective formulation associated with Minkowski metrics produces a robust tool for determining the best solutions in general, as well as the best solutions related to the maximum load that the columns can support. Finally, for both the single-objective and multi-objective problem analyses, increasing the slenderness of the columns resulted in more costly solutions, both economically and environmentally.

Journal of Composites Science doi: 10.3390/jcs10100515

Authors: Seong Baek Yang Hyoungjin Ji Dong-Jun Kwon

Carbon fiber-reinforced composites provide exceptional specific strength for lightweight structures but are associated with high global warming potential (GWP) during production. This study evaluates the GWP reduction potential of carbon/flax fiber hybrid composites for a one-piece main frame of a children’s bicycle. A simplified, scenario-based assessment was performed using a 3.0 kg reference mass and a fixed 70:30 reinforcement-to-resin mass ratio. The analysis varied flax substitution levels (0–40 wt.%), resin systems (epoxy and unsaturated polyester), manufacturing processes (resin transfer molding and prepreg/press), and end-of-life (EoL) treatments (incineration and landfill). Increasing flax content consistently reduced GWP across all scenarios. At 40 wt.% flax substitution, resin transfer molding achieved a 29.6–32.7% GWP reduction, whereas prepreg/press processing yielded a 21.5–23.0% GWP reduction. Material production dominated the GWP footprint in molding processes, whereas higher manufacturing burdens in prepreg/press routes partially offset the substitution benefits. GWP break-even mass ratios ranged from 1.273 to 1.486, indicating that hybrid frames can accommodate moderate mass increases without compromising environmental advantages. These results demonstrate that flax hybridization effectively reduces GWP, though the magnitude of reduction depends critically on manufacturing and EoL management choices. The proposed screening framework provides a practical tool for early-stage material and process selection in lightweight composite design.

Journal of Composites Science doi: 10.3390/jcs10100514

Authors: Marco Colombo Maurizio Pascadopoli Noemi Virgili Luca Franzoso Giampiero Pietrocola Andrea Scribante

Objectives: This in vitro study evaluated the effect of prolonged exposure to aqueous solutions with different pH values on the surface microhardness of four commercially available resin composites, simulating conditions associated with gastroesophageal reflux disease (GERD). Methods: Fifty standardised discs were prepared for each composite resin and allocated to five groups: a non-immersed control group and four groups immersed in solutions at pH 2.5, 5.0, 7.4 or 8.0. Samples were stored at 37 °C, after surface microhardness was measured using Vickers test after 24 h and after 7 days of immersion. Statistical analysis was performed using repeated-measures ANOVA, followed by Tukey’s post hoc test and linear regression analysis (p < 0.05). Results: All the materials showed a significant reduction in surface microhardness after immersion compared with the non-immersed controls (p < 0.05). Flowable composites exhibited consistently lower microhardness values than packable composites, and microhardness generally decreased after 7 days compared with 24 h. Linear regression analysis identified the composite formulation (commercial product tested), composite type (packable or flowable), and immersion time as significant determinants of microhardness (p < 0.05). Overall, these findings indicate that prolonged aqueous exposure, rather than pH itself, was primarily responsible for the reduction in surface microhardness. Significance: Within the limitations of this in vitro study, composite formulation and immersion time had a greater influence on surface microhardness than solution pH. These findings may help guide the selection of restorative materials for patients with gastroesophageal reflux disease.

Journal of Composites Science doi: 10.3390/jcs10100513

Authors: Ahmet Refah Torun Özgür Can Naghdali Choupani Ufuk Dirmencioğlu

The advances in 3D-printing technology add new dimensions to the already very versatile composite manufacturing methods. Polylactic acid (PLA) filaments are widely used for 3D printing. The low price and the biodegradability of PLA are major advantages; however, the lower fracture toughness is a drawback compared to conventional plastics, which are mass-produced with injection molding. The PLA/carbon filaments contain a 20% carbon volume ratio to increase the strength and the conductivity of the 3D-printed structures. The purpose of this study was to investigate the effects of infill pattern and density on the mixed-mode fracture behavior of 3D-printed PLA/carbon types of gyroid, cross, and triangle samples, with different infill percentages of 20%, 40%, and 60%. The type of failure displayed by the gyroid system resulted in higher fracture toughness values than those exhibited by the cross and triangle systems for all infill patterns under both mode-I and mode-II loadings. The enhanced fracture toughness and higher performance under mixed-mode loading in gyroid architectures compared to other systems indicate that they offer good resistance to crack propagation and present them as high-performance candidates for lightweight structural components. This study could offer a new path for printing parts based on fiber-reinforced polymer composites for several structural applications.

Journal of Composites Science doi: 10.3390/jcs10100512

Authors: Jiong Lin Jinxiu Wu Qi Lu Zhaohang Wu Meng Zhang Yanhong Hu Xiaowei Zhang Feng Guo Peng Guo

Calcium sulphate whiskers (CSWs) are a family of one-dimensional calcium sulphate crystals with different hydration states, which can be generally expressed as CaSO4·nH2O, where n = 2, 0.5, or 0 for calcium sulphate dihydrate whiskers (DH-CSW), calcium sulphate hemihydrate whiskers (HH-CSW), and anhydrous calcium sulphate whiskers (AH-CSW), respectively. Owing to their high strength, high modulus, low density, and favourable thermal stability, these whiskers have significant application potential in polymer composites, building materials, papermaking, and environmental remediation. However, the agglomeration issues arising from CSW’s highly polar surface and large specific surface area lead to insufficient interfacial compatibility with the matrix, severely limiting its reinforcement and toughening efficacy. Consequently, this paper provides a systematic review of surface modification techniques for CSW, focusing on modification methods, modifier structural selection, and surface interaction mechanisms. Particular emphasis is placed on composite synergistic modification: through organic-organic, inorganic-inorganic, and inorganic-organic composite strategies, complementary synergies between different modification mechanisms are achieved, effectively enhancing the interfacial bonding stability and functional integration of the modified layer. Finally, the paper notes that current research still faces key challenges, including insufficient microscopic analysis of modification mechanisms, unclear structure-effect relationships between modifiers and modification outcomes, and a lack of green, scalable processes. Future efforts should integrate multi-scale interfacial characterisation with molecular simulations, optimise modifier selection and composite synergistic strategies, develop eco-friendly and efficient modification systems, and establish a controllable, functionalised framework for interfacial design. This will provide a theoretical foundation for the high-value application of CSW in high-performance composites and advanced functional materials.

Journal of Composites Science doi: 10.3390/jcs10100511

Authors: Shakir Azim Ruben Vande Ryse Dagmar R. D’hooge Mariya Edeleva Ludwig Cardon Patrick De Baets

Key processing technologies for polymers include traditional injection moulding (IM) and emerging 3D printing or additive manufacturing (AM). The meso-scale structuring and the degree of degradation during processing are likely different for IM and AM, affecting the material properties of the produced parts. Here, studies that examine both mechanical and tribological behaviour remain rare, specifically for less studied materials such as polyesters. In this work, we selected polyethylene terephthalate-glycol (PETg) as the matrix, incorporating polytetrafluoroethylene (PTFE) and solid lubricants such as hexagonal boron nitride (h-BN) or expanded graphite (EG), to compare IM and AM mechanical and tribological performance under similar degradation conditions, as verified by gel permeation chromatography. The thermal properties were not altered by the addition of fillers, while the mechanical properties, i.e., tensile modulus and impact strength, could be tuned through the addition of specific levels of additives. Once the specific load of the additives was reached, we observed a reduction in the specific wear rate. The findings suggest that well-optimised filler combinations and robust processing control can significantly enhance the performance of PETg composites.

Journal of Composites Science doi: 10.3390/jcs10100510

Authors: Yuxin Huang Chonggen Pan Danna Su Baolin Peng Chuansheng Xiong

To further enhance the mechanical performance and early-age crack resistance of engineered cementitious composites (ECC), an ECC-based multiscale hybrid-fiber system was investigated. The system used carbon nanotube-modified polyethylene (M-PE) fibers as the primary reinforcement together with polypropylene (PP) and basalt (BF) fibers. The effects of fiber hybridization on compressive strength, uniaxial tensile behavior, flexural performance, early-age crack resistance, and microstructure were systematically evaluated. Mixtures retaining at least 60% M-PE exhibited a clear post-cracking strain-hardening response, whereas lower M-PE fractions led to crack localization and loss of strain hardening. At 28 days, BF-0 (1.5 vol.% M-PE + 0.3 vol.% BF) reached compressive, tensile, and flexural strengths of 85.3, 7.35, and 36.38 MPa, respectively. A six-indicator entropy-weighted TOPSIS evaluation identified BF-0 as the best-balanced mixture among the investigated groups. Increasing PP or BF content improved early-age plate crack resistance; BF-5 (1.5 vol.% BF) achieved the highest crack reduction coefficient of 67.98%, with a nominal total crack area of 27.6 mm2. Scanning electron microscopy (SEM) observations were used only as qualitative morphological evidence, whereas mercury intrusion porosimetry (MIP) revealed quantitative pore-structure trends and X-ray diffraction (XRD) indicated that fiber hybridization did not generate new detectable crystalline phases. The results reveal the performance trade-offs among strength, ductility, and early-age crack control in multiscale hybrid-fiber cementitious composites.

Journal of Composites Science doi: 10.3390/jcs10100509

Authors: S. N. Danilova S. B. Yarusova E. K. Papynov P. N. Tarasova Iu. V. Kapitonova P. A. Marmaza O. O. Shichalin N. P. Ivanov D. K. Tsygankov V. L. Rastorguev A. V. Okoneshnikova V. Yu. Maiorov P. S. Gordienko A. A. Okhlopkova

Ultra-high molecular weight polyethylene (UHMWPE) suffers from low wear resistance and an insufficient elastic modulus, limiting its use in friction units. In this study, UHMWPE-based composites filled with wollastonite (0.5–5 wt.%) derived from boric acid production waste via alkaline treatment at room temperature and calcination at 900 °C were fabricated. Filler distribution in the subsurface layer under sliding friction was examined using XRD, FTIR, Raman spectroscopy, and SEM with energy-dispersive X-ray mapping. Concentration-dependent particle migration was observed: at 0.5–1 wt.%, wollastonite migrates toward the friction surface, while at 5 wt.%, migration is suppressed. Wollastonite agglomerates participate in the formation of secondary tribostructures that control wear resistance. The introduction of 0.5 wt.% wollastonite led to a 15% increase in tensile strength and an eightfold reduction in wear rate (from 0.57 × 10−6 to 0.07 × 10−6 mm3/(N·m)). At 5 wt.%, the elastic modulus increased by 30%. The correlation between the distribution patterns, contact-zone temperature, and wear mechanisms is discussed. Controlling filler migration and agglomeration in the subsurface layer is considered the key to producing high-quality polymer composite materials (PCMs) with predictable tribological properties.

Journal of Composites Science doi: 10.3390/jcs10100508

Authors: Gizem Özge Kayan Asgar Kayan

The increasing discharge of pharmaceuticals, dyes, and toxic ions has intensified the need for efficient adsorption and degradation technologies. Metal–organic frameworks (MOFs) have attracted considerable attention for environmental remediation, owing to their well-defined porous structures, exceptionally high specific surface areas, abundant accessible active sites, tunable pore architectures, and structural diversity. However, the practical application of pristine MOFs is often hindered by several limitations, including inadequate stability in aqueous environments and limited mass-transfer efficiency. These drawbacks can significantly restrict the large-scale and industrial utilization of MOF materials. The integration of MOFs with functional materials such as carbonaceous substrates, polymers, metals/metal oxides, porous silica, magnetic nanoparticles, COFs, MOFs, POMs, graphitic carbon nitride, MXenes, and enzymes enhances their stability, hydrophobicity, dispersibility, electron-transfer capability, mechanical strength, and reusability. These synergistic effects enable MOF composites to achieve remarkable performance in the removal of a wide range of contaminants through adsorption and catalytic degradation processes. This review provides a systematic overview of recent progress in MOF-based composites for the removal of dyes, pharmaceutical contaminants, and metal ions, as well as their applications in drug delivery. A particular emphasis is placed on composite design strategies, structure–performance relationships, and the synergistic mechanisms responsible for the enhanced functionality of different composite systems.

Journal of Composites Science doi: 10.3390/jcs10100507

Authors: Elmer Marcial Cervantes-Ramírez Danna Lizeth Trejo-Arroyo Julio César Cruz Argüello Gerardo Manuel Rodríguez Torres Mayra Zyzlila Figueroa Torres Javier Rodrigo Nahuat Sansores

Population growth, high ambient temperatures, and longer warm periods have led to increased energy consumption related to heating and cooling systems. The building envelope plays a fundamental role in the performance of such systems to reduce heat transfer into buildings. This study evaluated the effect of incorporating phase change materials (PCMs), namely Glauber’s salt and calcium chloride hexahydrate, into a cement-based mortar. The PCMs were impregnated into basalt aggregate used as a supporting medium and encapsulated. The physicochemical, mechanical, and thermal properties of the mortars were characterized before and after PCM incorporation. The mortars with PCMs exhibited reductions in thermal conductivity of 48% and 53%, thermal diffusivity of 40% and 45%, and volumetric heat capacity of 17% and 24%, respectively, as determined according to ASTM D5334. Thermal performance was evaluated using hot-box equipment, demonstrating a reduction in the temperature fluctuation of up to 2.865 °C and average reductions in maximum temperature peaks of 0.3106 °C. Compressive strength revealed reductions of 61% and 76% relative to the reference mortar for each modified mortar. PCM-modified mortars satisfied the minimum requirements established for non-structural rendering applications and exhibited a substantial improvement in overall thermal performance. These results suggest their potential use as passive coating materials for thermal management in buildings.

Journal of Composites Science doi: 10.3390/jcs10100506

Authors: Mohamed Moafak Arbili

This study investigated the performance of concrete incorporating fly ash (FA) and bentonite (B) as partial replacements for ordinary Portland cement (OPC). Ten mixtures were evaluated: one OPC control, five binary mixtures containing 10–30% FA, and four ternary mixtures with a fixed total replacement of 30%, comprising FA/B replacement percentages of 20/10, 15/15, 10/20, and 5/25 by total binder mass. The total binder content and nominal water-to-binder ratio were maintained at 430 kg/m3 and approximately 0.55, respectively. Fresh-state and binder-paste properties, compressive and splitting tensile strengths, hardened density, water absorption, hydrochloric-acid resistance, sorptivity, and ultrasonic pulse velocity were assessed. FA20B10 provided a favorable balance of mechanical and durability-related performance among the tested ternary mixtures, whereas FA30 achieved the highest overall 90-day compressive strength of 33.1 MPa. Water absorption decreased from approximately 7.6% for the control to 5.1% for FA20B10. The ternary mixtures also exhibited lower sorptivity and smaller strength losses following hydrochloric-acid exposure than the control. A provisional partial material-cost comparison was restricted to the control and binary mixtures and did not establish the cost-effectiveness of the ternary formulations. Environmental reporting was limited to a mass-based, OPC-only screening estimate using a fixed emission factor. Emissions associated with FA, B, other constituents, and the remaining life-cycle processes were excluded; therefore, the calculation does not establish the total concrete carbon footprint or a life-cycle CO2 reduction. The findings support further development of fly-ash–bentonite ternary concrete, subject to source-specific characterization and field-scale validation.

Journal of Composites Science doi: 10.3390/jcs10100505

Authors: Lucas de Mendonça Neuba Ary Machado de Azevedo Belayne Zanini Marchi José Carlos Ferreira Fontes Alexandre Alvarenga Palmeira Maria Teresa Gómez del-Río Sergio Neves Monteiro

Composite materials, particularly those with fiber-reinforced polymer matrices, align well with current demands for combining low density with high mechanical strength. This has motivated extensive research into natural lignocellulosic fiber-reinforced polymeric matrices. In this context, the present study evaluates the toughness of untreated and alkali-treated 30 vol.% sedge fiber (Cyperus malaccensis)-reinforced epoxy matrix composites. This study provides a comprehensive assessment of dynamic and quasi-static mechanical properties. The dynamic toughness performance was evaluated through Izod and Charpy impact, whereas quasi-static toughness was evaluated using tensile, flexural, and compressive tests. To allow for a proper comparison, toughness units were all considered in joules (J) by taking into account the specimen dimensions. The fracture surfaces were examined to evaluate the influence of fiber treatment on failure mechanisms. Scanning electron micrographs depicted a substantial reduction in interfacial delamination of composites reinforced with treated fibers, suggesting improved fiber–matrix adhesion. The results revealed a significant difference attributable to the alkali treatment. Specifically, the treated-fiber composite group showed the highest impact energies, achieving values of 7.84 J for Izod and 15.5 J for Charpy. The alkali-treated fiber composites exhibited quasi-static energy absorption values of 2.78 J, 4.32 J, and 11.06 J under tensile, flexural, and compressive loading, respectively.

Journal of Composites Science doi: 10.3390/jcs10090504

Authors: Joseph J. Marcinko Anthony A. Parker James H. P. Collins Josh Tyler

Magnetic resonance imaging (MRI) is a well-established technique used in medical applications and bio-based research. It has also been used to study wood and composite materials of various types. Soy-based adhesives used in hardwood plywood applications are not very moisture-resistant. We have employed MRI to study water-soaked plywood composites made with soy adhesives in an attempt to gain insight into how water interacts and affects the soy adhesive bondlines. Various MRI data acquisition sequences were used to show how water interacts and migrates within the soy adhesives and to quantify the presence of water at the bondline of the plywood samples. The data from MRI was combined with cyclic testing data of plywood to help understand how soy adhesives can be modified to reduce their moisture sensitivity. MRI of plywood bondlines made with chemically modified soy adhesives shows that moisture ingress can be reduced dramatically. Cyclic water soak/drying testing of plywood made with chemically modified soy adhesives shows that the reduction in moisture sensitivity results in dramatic improvements in bondline durability, as measured by the ANSI/HPVA EF 2020 cyclic testing protocol for hardwood plywood.

Journal of Composites Science doi: 10.3390/jcs10090503

Authors: Patrick Adegbaye Aigbe E. Awenlimobor Justin An Jiajun Xu

Air-to-air heat exchangers are vital for energy recovery and thermal management but often suffer from reduced effectiveness, high pressure losses, and increased pumping power in conventional designs. Advances in additive manufacturing have enabled nature-inspired geometries, such as lattice and triply periodic minimal surface (TPMS) structures, which enhance heat transfer through complex first-order surfaces but are frequently associated with excessive pressure drops. This study proposes an optimized higher-order harmonic heat transfer surface tessellation developed through an optimization framework integrating analytical and numerical methods. The goal is to improve the overall thermal–hydraulic performance of the heat exchanger over a range of operating conditions. Results of the sensitivity analysis show that secondary surface modification of this type can yield a significant increase in effectiveness reaching up to 14%, although with an associated increase in the pressure drop. Additionally, we show that the optimized second-order harmonic-type structure achieved relatively higher effectiveness for comparable but slightly lower pressure drop than the gyroid structure across the flow regimes considered. While the gyroid structure outperformed the optimized harmonic-type structure in terms of the fin geometry heat transfer efficiency assessed based on the London goodness factor, j/f1/3 by a factor of 1.9, the optimized harmonic-type structure had relatively higher energy efficiency than that of the gyroid structure across the entire spectrum of operating conditions reaching up to a factor of about 1.6 in the laminar flow regime. The findings from this study demonstrate a balanced pathway for additively manufacturable, high-performance air-to-air heat exchangers, offering compact, energy-efficient solutions for applications in building ventilation, aerospace, and electronics cooling.

Journal of Composites Science doi: 10.3390/jcs10090502

Authors: Christopher Varela Luis Longas Fahim Faysal Jayanta Bhusan Deb Yiting Wang Chiranjit Maiti Kareem Ahmed Jihua Gou

Ceramic matrix composites (CMCs) are promising thermal-protection materials for hydrogen-fueled gas turbines, where components are exposed to high temperatures, steam-rich combustion products, and pressure-driven heat transfer. This study investigates yttria-stabilized zirconia (YSZ) fiber-reinforced polymer-derived ceramic composites fabricated by polymer infiltration and pyrolysis (PIP) using Durazane-1800 as the preceramic precursor. Eight-layer YSZ preforms were rigidized, vacuum-infiltrated, cured, and pyrolyzed at 950 °C in nitrogen; repeated PIP cycles were used to increase matrix densification. Under hydrogen torch exposure at a heat flux of 180–190 W/cm2, the front-face temperature of the CMC coupon reached approximately 1400 °C while the back-face temperature stabilized near 600 °C during a 10 min test, with no observed delamination or burn-through. Post-test SEM/EDS and XRD characterization indicated oxidation of the SiCN matrix and the deposition of a silica-rich substance on the material surface. In a hydrogen-combustion rig, the CMC liner reduced the external wall temperature relative to the unlined wall by approximately 32 °C at 1 atm and 17 °C at 5 atm. Transient thermal simulations reproduced the measured temperature trends with differences of approximately 3.8–7.8% for selected temperatures at 1 atm and 6.2% for the liner back-face temperature at 5 atm. Increasing the number of PIP cycles from two to seven increased fracture strength from 7.87 to 19.77 MPa and flexural modulus from 4.05 to 24.34 GPa. These results demonstrate the potential of YSZ-reinforced polymer-derived CMCs as thermal barriers for hydrogen-combustion environments and identify porosity control as a key requirement for improved high-pressure performance.

Journal of Composites Science doi: 10.3390/jcs10090501

Authors: Michal Jasiczek Marcelina Bobrowska Arnold Jedral

Continuous-fiber composite laminates based on Inconel 601 reinforcement and a geopolymer-derived aluminosilicate matrix were fabricated using a slurry-impregnation/prepreg processing route followed by low-temperature consolidation and post-curing. The objective of this study was to evaluate the flexural and tensile properties, as well as the thermo-oxidative behavior, of this composite system. The as-fabricated laminates exhibited a bulk density of 4.05 ± 0.08 g/cm3 and an apparent porosity of 24.88 ± 0.62%. Tensile testing showed measurable mechanical properties for both unidirectional and balanced laminate architectures. The [0]8 laminates exhibited tensile strengths of approximately 327–365 MPa from room temperature to 538 °C, while the [0/90]2S laminates showed a decrease in room-temperature tensile strength, consistent with the lower fraction of load-bearing 0° fibers. Thermo-oxidative exposure in air at 538 °C for 336 h produced no measurable reduction in room-temperature flexural strength; accordingly, accelerated oxidation tests were conducted at higher temperatures to promote observable degradation. These tests indicated a transition from limited oxidation at 538 °C to more uniform oxidation at intermediate temperatures and to more aggressive, localized fiber attack at 816 °C. These results suggest that the material system, although still in its developmental stage, is a candidate for further development toward intermediate-temperature applications (approximately 300–600 °C).

Journal of Composites Science doi: 10.3390/jcs10090500

Authors: Johanna Gaitán-Álvarez Rosilei Garcia Véronic Landry Alain Cloutier

Medium-density fiberboard (MDF) is widely used for embossed door panels. The fiber refining process is crucial for determining both surface quality and mechanical performance of these panels. This study investigated how different refining conditions affect fiber granulometry, surface quality, and mechanical properties of embossed MDF door panels. Three key refining parameters were investigated: digester steam pressure (0.8 and 0.9 MPa), refiner specific energy (70 and 80 kWh/t), and refiner differential pressure (24, 35, and 50 kPa). Panel properties were evaluated in terms of vertical density profile, surface roughness, bending properties, and cleavage strength. Statistical analysis revealed that refining parameters significantly affected fiber granulometry, as well as the average and surface density of the panels. Surface roughness, however, showed minimal variation under the refining conditions considered. In contrast, the bending properties—modulus of rupture (MOR) and modulus of elasticity (MOE)—were significantly improved, with MOR and MOE increasing by up to 12% relative to the control (48.0 vs. 42.7 MPa and 4.6 vs. 4.1 GPa, respectively). Cleavage strength also varied with refining conditions but remained comparable to the control across all treatments. Overall, the results indicate that optimized refining conditions can enhance MDF door panel performance, particularly bending properties, without compromising surface quality or cleavage strength.

Journal of Composites Science doi: 10.3390/jcs10090499

Authors: Prashantha Acharya Dayananda Pai Chethan K N G. T. Mahesha

Natural fiber-reinforced composites have attracted considerable interest because of their eco-friendly nature and impressive mechanical properties. Numerical models of composites are helpful to predict the behavior of materials before actual testing or application. In the current study, chemically modified Helicteres isora fiber-reinforced Polylactic acid composites were evaluated to determine the Poisson’s ratio using Digital Image Correlation analysis and static structural simulation of the laminated composites to predict the tensile and flexural behavior of the composites. The modeling of Laminated composites for static structural simulation was done using ANSYS ACP (PrepPost). The properties of the fiber mat and matrix material, as per the experimental study, were considered for the simulation input parameters. The layers of the laminated composite specimens in experimental work were replicated in ANSYS ACP. The static structural analysis was accomplished to find the maximum equivalent stress, maximum deflection, and stress distribution patterns in tensile and flexural models. The deviation in the results of the simulation from the experimentally obtained results was 2.70% and 1.80% in tensile and flexural stress, and 4.48% and 5.03% in tensile and flexural deformation, respectively.

Journal of Composites Science doi: 10.3390/jcs10090498

Authors: M. M. Nour Maha A. Tony Hossam A. Nabwey

The growing demand for sustainable and energy-efficient systems has accelerated the development of multifunctional materials capable of simultaneously storing, regulating, and conserving thermal energy. Metal–organic framework (MOF)–based phase change material (PCM) composites have emerged as promising candidates for thermal and hygrothermal energy storage because of their tunable porosity, surface chemistry, and structural adaptability. This review critically examines the relationships among MOF architecture, PCM confinement, interfacial interactions, heat and moisture transport, cycling stability, and application-specific performance. Particular emphasis is placed on the multidimensional trade-offs governing composite design. Increasing PCM loading can improve latent-heat capacity but reduce the pore accessibility required for moisture buffering, whereas the incorporation of conductive fillers can enhance heat transfer at the expense of gravimetric energy-storage density. Likewise, highly hydrophilic frameworks favor moisture regulation but may exhibit lower hydrothermal stability, while mechanically robust and scalable formulations may require compromises in porosity, PCM loading, or interfacial performance. Comparative assessment across building, solar-thermal, electronic, textile, and environmental applications further shows that no single MOF–PCM configuration can simultaneously maximize latent-heat storage, thermal conductivity, humidity control, mechanical integrity, durability, and manufacturability. Accordingly, rational MOF–PCM development should follow a multi-objective, application-specific design strategy that balances structure, interface, performance, stability, and scalability rather than optimizing a single property. These insights provide practical guidance for the development of next-generation multifunctional thermal and hygrothermal energy-storage materials.

Journal of Composites Science doi: 10.3390/jcs10090497

Authors: Kaster Kamunur Zarina Shnali Aibek Makan Lyazzat Mussapyrova Sandugash Tanyrbergenova Nurzhamal Zhylybayeva Dana Assylkhanova Meiram Atamanov

Cu is central to electrification and low-carbon technologies, while declining ore grades and environmental pressures increase interest in recovery from secondary liquid resources. This review critically evaluates copper separation from mine-affected waters, copper-smelting waste acids, electroplating wastewaters, and secondary-material leachates. Cu is the principal target; co-occurring metals are treated as competitors or sequential recovery targets. Feed origin, Cu concentration and speciation, pH/free acidity, ionic strength, ligands, and polymetallic composition are related to process performance and product form. Conventional precipitation, solvent extraction, ion exchange, and electrowinning are compared with microfiltration, ultrafiltration, nanofiltration, reverse osmosis, electrodialysis, supported liquid membranes, emulsion liquid membranes, and polymer inclusion membranes. High Cu removal or rejection does not by itself demonstrate Cu-selective recovery. MF and UF require conversion of dissolved Cu into retainable species; NF and RO mainly recover water and preconcentrate metals; ED becomes more selective with speciation control; and carrier-mediated membranes can fractionate metals but face stability constraints. Most membrane processes generate a Cu-rich retentate, concentrate, or stripping solution rather than metallic Cu and therefore require downstream crystallisation or electrowinning. Key gaps are long-term operation with variable industrial feeds, fouling and scaling control, mass balances and product-purity reporting, membrane/carrier durability, and consistent techno-economic validation.

Journal of Composites Science doi: 10.3390/jcs10090496

Authors: Helen Paola Toledo Jaldín Oscar Roberto Montes-Moreno Alien Blanco Flores Delia Monserrat Ávila-Márquez Josué Valdés-García Alejandro Dorazco-González Martha Stephanie Pérez Mendoza

Methyl parathion (MP) is an organic pesticide used on crops to control pest populations. However, its indiscriminate use contaminates soil and water, necessitating the development of cost-effective solutions for its removal and detection. In this work, a novel luminescent composite (Pi@Tb-MOF) was successfully synthesized via the in situ growth of a terbium-based metal–organic framework on pistachio shell biomass. The successful formation of the Pi@Tb-MOF composite was confirmed by XRD, SEM-EDS, FTIR, and TGA analyses. The composite was evaluated for the removal and detection of MP in aqueous media. Kinetic data were best described by the second-order and Avrami models, which indicate heterogeneous surface reactions and progressive activation of adsorption sites. Isotherm analysis revealed that the Hill model provided the best fit (KH = 0.6644), suggesting cooperative adsorption and strong adsorbate–adsorbate interactions on the composite surface. Although the maximum adsorption capacity predicted by the Langmuir model was 1.47 mg/g, the material exhibited a remarkable luminescence response to MP. The Tb-MOF characteristic emission bands decreased progressively upon pesticide adsorption, enabling fluorescence-based detection with a limit of detection of 0.1 µM. The quenching process followed a linear Stern–Volmer relationship at low concentrations (R2 = 0.99), demonstrating the composite’s potential as a sensing platform. The fluorescence quenching is attributed to electron transfer interactions between the MOF ligand and the nitroaromatic group of MP combined with adsorption on the pistachio matrix. These results demonstrate that Pi@Tb-MOF is a sustainable composite capable of simultaneously removing and detecting methyl parathion, highlighting its potential as an environmentally friendly material for monitoring pesticide contamination in water. This work reports, for the first time, a novel Pi@Tb-MOF composite based on pistachio shell biomass and a luminescent Tb-MOF, which has not been previously described in the literature and enables the simultaneous adsorption and optical sensing of methyl parathion.

Journal of Composites Science doi: 10.3390/jcs10090495

Authors: Stefano Bellucci

This study examines how filler-specific processing and the resulting spatial organization govern the structural response and measured electrical behaviour of epoxy nanocomposites containing graphene nanoplatelets (GNP), graphene oxide (GO), or molybdenum disulfide (MoS2). Bulk specimens and spin-coated films containing 0.25–5 wt% nominal filler were prepared with 22 wt% and 8 wt% A1 amine hardener, respectively. GNP and MoS2 formulations required pulsed sonication followed by planetary mixing, whereas GO was processed by planetary mixing alone; temporary isopropanol was additionally required for the nominal 5 wt% GNP formulation. Film thickness, low-frequency impedance, diamond-ATR FTIR spectra, Raman spectra, and planar and cross-sectional Raman maps were evaluated. Films from the higher nominal GNP-loading formulation showed the clearest increase in mean thickness, consistent with concentration-dependent rheology and platelet interactions during spin coating. The impedance response was strongly contact-sensitive. Under identical embedded-contact conditions, the specimen prepared from the nominal 5 wt% GNP formulation exhibited substantially lower impedance than neat epoxy across the common frequency range, with a median |Z_GNP|/|Z_epoxy| ratio of approximately 0.16. The persistence of this difference across the common frequency interval provides a clear same-fixture electrical distinction between the two tested specimens. Because one specimen was examined per condition, this result is reported at the specimen level and is not used to assign bulk conductivity, a unique conduction mechanism, or a numerical percolation threshold. ATR-FTIR showed preservation of the epoxy fingerprint together with the oxygen-rich GO contribution, while Raman spectroscopy retained the characteristic carbon and MoS2 signatures. Raman mapping showed isolated filler-rich domains at nominal 0.25 wt% and broader, more spatially continuous domains at nominal 5 wt% for the matched GNP and GO datasets, while cross-sectional mapping confirmed subsurface filler signatures for all three systems. Together, the results establish a processing–structure–measurement framework for these three 2D-filler/epoxy systems and identify the experimental controls needed for reliable interpretation of functional response.

Journal of Composites Science doi: 10.3390/jcs10090494

Authors: Dorivane Cohen Farias Diogo Monteiro Porfírio Miriane Alexandrino Pinheiro Mário Edson Santos de Sousa Alessandro José Gomes dos Santos Douglas Santos Silva Raí Felipe Pereira Junio Sergio Neves Monteiro Marcos Allan Leite dos Reis

This study investigates the combined influence of multi-walled carbon nanotube (MWCNT) concentration and structural architecture on the compressive behavior of fused filament fabrication (FFF)-printed PLA components. Neat PLA and PLA reinforced with 1.0 and 2.0 wt% carboxyl-functionalized MWCNTs were characterized by Raman spectroscopy, DSC, TGA, compression testing, statistical analysis, and scanning electron microscopy. Thermal characterization showed that MWCNT incorporation caused only minor changes in PLA thermal degradation while altering its crystallization behavior. For nearly solid specimens (90% infill), compressive strength increased from 53.4 MPa for neat PLA to 73.6 MPa at 2.0 wt% MWCNTs, although differences among MWCNT concentrations were not statistically significant. Honeycomb structures exhibited the highest mechanical performance at 1.0 wt% MWCNTs, reaching a compressive strength of 33.3 MPa, approximately 59% higher than that of neat PLA, with significant improvements in both compressive strength and elastic modulus. Two-way ANOVA revealed significant interactions between structural architecture and MWCNT concentration for both compressive strength and elastic modulus, demonstrating an architecture-dependent reinforcement response. SEM provided complementary morphological evidence consistent with the observed mechanical trends. These findings demonstrate that the most effective MWCNT concentration depends on structural architecture, highlighting the importance of simultaneously optimizing material composition and geometry in FFF-manufactured polymer nanocomposites.

Journal of Composites Science doi: 10.3390/jcs10090493

Authors: Aliya Kenzhegaliyeva Yerdos Ongarbayev

This study examined the effect of a graphene oxide-like (GO-like) carbon material obtained from lemon peel biochar on road bitumen. Pyrolysis of the raw material was conducted at 500, 550 and 600 °C. The graphene oxide-like carbon material was synthesized using a modified Hummers method. Among the investigated pyrolysis temperatures, 550 °C produced the most favorable structural characteristics, including a higher contribution of oxygen-containing groups and a more uniform structure. Adding a selected dosage of 3 wt.% graphene oxide-like carbon material increased shear stress by 20–25 kPa, ultimate strain from 13 to 17%, and fatigue life by 36–109%. The results confirm the potential of using lemon peel biochar to produce a road bitumen modifier.

Journal of Composites Science doi: 10.3390/jcs10090492

Authors: Pengfei Ma Shuming Jia Shangke Yuan

In view of the seismic performance deficiencies commonly observed in existing reinforced concrete (RC) frame structures, the application of fiber-reinforced polymer (FRP) composites for seismic strengthening has become a key technical approach to enhance the safety reserve of such structures. However, most existing studies primarily focus on the overall effectiveness of strengthening schemes, while systematic investigations on key geometric parameters, such as strengthening location and length, remain insufficient. In this paper, based on the ABAQUS finite element software and calibrated against a quasi-static test of a 1/2-scale two-story two-bay RC plane frame, refined numerical models of both unstrengthened and FRP-strengthened frames were established. Adopting a “control-variable parametric analysis” strategy and using cross-sectional dimensions as the reference, nine strengthening cases were designed with column-end FRP lengths of 0.5b, 1.5b, and 2.5b and beam-end FRP lengths of 1h, 2h, and 3h. The differential effects of FRP-strengthening lengths at beam and column ends on the seismic performance of the frame structure were revealed. The results indicate that FRP strengthening can effectively enhance the load-bearing capacity and improve the hysteretic performance of members. Nevertheless, the underlying mechanisms by which beam-end and column-end strengthening lengths affect mechanical behavior are fundamentally different: column-end FRP strengthening primarily governs the initial stiffness and load-bearing capacity, with a maximum increase in peak load of 40.7%; beam-end FRP strengthening mainly controls the post-yield stiffness degradation rate and energy dissipation capacity, achieving a peak load increase of up to 53.2%, although the marginal benefit tends to diminish with increasing length. Beam-end strengthening is the critical factor governing the transition of failure mode (from brittle joint shear failure to ductile beam-end flexural failure), while column-end strengthening plays a supplementary role in restraining the formation of column hinges and maintaining the desirable “strong column-weak beam” failure hierarchy. This study reveals the influence of FRP strengthening length on the seismic performance of structures, and to some extent addresses the deficiency of existing studies in systematic parametric analysis.

Journal of Composites Science doi: 10.3390/jcs10090491

Authors: Suadad Noori Ghani Haithem Abdulla Moftin Raghad Azeez Neamah Abbas Ali Diwan

This study was conducted to discover nanocomposite materials with high stiffness and toughness to meet industrial requirements, particularly for applications that demand high durability and abrasion resistance, such as mud pump pistons and sealing components. A nanocomposite constructed of natural rubber/polybutadiene rubber at a 90/10 ratio was combined with 48 phr black carbon and multi-walled carbon nanotubes (MWCNTs) at different proportions: 0, 0.96,1.28 and 1.6 phr, reduced from 48 phr. The maximum tensile strength was observed for rubber with a nanocarbon content of 1.28 phr, representing an increase of 111% compared to that of neat rubber. The elongation at break was 3.2 in rubber with 1.28 phr of MWCNT, an increase of 53.5% compared to that of neat rubber. The minimum weight loss was 0.07 g in the abrasion resistance test in rubber with 1.28 phr of MWCNT. This represents a decrease in weight loss of 22.22% compared to the results for neat rubber.

Journal of Composites Science doi: 10.3390/jcs10090490

Authors: Seong-Hyun Kang Se-Hun Kim Kwan-Woo Kim Byung-Joo Kim

The recycling of carbon fiber-reinforced polymer (CFRP) is essential for reducing environmental pollution and improving resource efficiency. However, carbon fibers recovered during the recycling process are typically obtained in the form of short fibers, and the removal of sizing leaves the fiber surface unsized, resulting in deteriorated interfacial properties. In this study, an atmospheric-pressure plasma (APP) treatment applicable to continuous processing was employed to modify the surface characteristics of recycled carbon fiber (rCF) and promote more favorable interactions with an epoxy matrix. The surface characteristics of plasma-treated rCF were analyzed using temperature-programmed desorption, X-ray photoelectron spectroscopy, field-emission scanning electron microscopy, and single-fiber contact angle measurements. Furthermore, the mechanical performance of recycled carbon fiber-reinforced epoxy composites, hereafter denoted as rCFRP, fabricated with the treated fibers was evaluated through tensile and flexural testing. APP treatment increased the content of oxygen-containing groups on the rCF surface, with the O1s/C1s ratio increasing from 0.15 to 0.39 and the polar component of the surface free energy increasing from 14% to 32% which may have contributed to more favorable interactions with the epoxy matrix. The tensile and flexural strengths of the rCFRP composites increased by up to 59% and 58%, respectively, compared with those of the untreated rCFRP composites. This study demonstrates that APP treatment is an effective approach for surface modification of rCF and suggests its potential applicability to the continuous manufacturing of rCFRP composites.

Journal of Composites Science doi: 10.3390/jcs10090489

Authors: Wafa Shamsan Al-Arjan Lamia A. Ismail W. Christopher Boyd Islam Gomaa

The precise control of one-dimensional (1D) nanoscale architecture and facet-specific interfaces in alkaline earth metal oxides remains a critical challenge for developing advanced, multifunctional nanocomposites. Herein, we report the template- and surfactant-free mechanochemical synthesis of polyhedral magnesium oxide (MgO) nanorods via the pseudomorphic transformation of a magnesium citrate precursor (Mg-P), followed by systematic integration with graphene oxide (GO). Controlled thermal decomposition of the multiphase 1D coordination precursor yields phase-pure, shape-memory periclase nanorods that retain the precursor’s anisotropic <100> growth axis without undergoing structural collapse. Comprehensive structural and thermogravimetric analyses of the resulting MgO-GO nanocomposites (10, 30, and 50 wt.% GO) suggest a non-covalent, facet-specific interaction mechanism. GO nanosheets are shown to preferentially adhere to the {100} prismatic facets of the MgO nanorods, inducing anisotropic compressive strain, impeding lateral crystallite coarsening, and elevating the autocatalytic deoxygenation temperature of GO by over 145 °C. Furthermore, electrokinetic, and hydrodynamic assessments demonstrate an anomalous, composition-dependent colloidal evolution. While initial GO loadings mask the basic MgO surface to trigger massive hydrodynamic expansion, reaching an equimass 50 wt.% loading forces a profound electrokinetic inversion (+33.5 mV) and volumetric compaction, as the highly basic MgO interfaces re-establish dominance over the hydrodynamic shear plane. The data support a pseudomorphic route under the current conditions for the shape-directed synthesis of 1D metal oxides from coordination precursors and unravel the primitive interfacial dynamics governing the structural and colloidal stability of metal oxide–graphene hybrids.

Journal of Composites Science doi: 10.3390/jcs10090488

Authors: Nurlan Zhangabay Akmaral Utelbayeva Bolat Duissenbekov Svetlana Buganova Timur Tursunkululy

This article investigates the numerical simulation of heat-and-aerodynamic cycles in the ventilated air gap of a multilayer composite wall façade system in a hot climate using ANSYS 19/2 Fluent. Standard normative techniques rely on averaged, stationary boundary conditions and account for neither the height-wise inequality of solar exposure nor the dependence of air density and viscosity on barometric pressure and temperature, resulting in significant errors in predicting the actual heating of such structures. The model was calibrated on the authors’ own full-scale, in situ measurements of temperature, air speed and solar exposure in the ventilated gap of a nine-storey building, from which linear height-dependent surface-temperature relations were derived and used as boundary conditions for 3D models of façades 25 and 60 m tall. Thirty-two finite-volume experiments were performed under free convection (Boussinesq approximation), varying gap width (5 and 10 cm), inlet width (20 and 40 cm), barometric pressure (690 and 770 mmHg) and external air temperature (20 and 40 °C). Façade height proved the dominant factor (air speed up to 1.8 times higher, temperature 3–12.1 °C higher), followed by gap width (speed lower by 1.7 times, temperature by 3–5 °C), whereas pressure and inlet width altered the results by no more than 6%. Discrepancies with the standard calculation reached 10 °C in temperature and a two-fold difference in flow speed, confirming the need for verified CFD simulation when designing ventilated composite wall façades in hot climates.

Journal of Composites Science doi: 10.3390/jcs10090487

Authors: Ahmed Hemida Louay N. Mohammad Samuel B. Cooper

Asphalt mixtures are heterogeneous composite materials primarily composed of mineral aggregates and asphalt binder; depending on the mixture design, they may also incorporate reclaimed asphalt pavement (RAP) and polymer-modified binders. Their long-term performance is governed by the rheological evolution of the asphalt binder and its interactions with surrounding composite constituents during aging. Existing laboratory long-term aging (LTA) protocols have been developed primarily to evaluate mixture cracking resistance; however, their ability to reproduce the high-temperature rheological evolution of recovered asphalt binders remains insufficiently understood. This study evaluated the fidelity of accelerated LTA protocols by comparing the high-temperature rheological response of binders recovered from plant-produced asphalt mixtures with the conventional benchmark of 85 °C for 5 days. Five mixtures, including one containing an unmodified PG 67-22 binder with RAP and four containing SBS-modified PG 76-22 binders with varying RAP contents, were characterized using continuous high-temperature performance grade (PG-HT), dynamic shear rheometer rutting parameter (|G*|/sinδ), zero-shear viscosity, multiple stress creep recovery, and interrupted shear flow. Among the investigated protocols, loose-mixture aging at 135 °C for 6 h showed the closest agreement with the benchmark rheological response, whereas 135 °C for 8 h and 120 °C for 20 h produced greater rheological stiffening relative to the benchmark. The unmodified PG 67-22 binder exhibited the greatest aging sensitivity, while SBS-modified binders showed closer agreement overall.

Journal of Composites Science doi: 10.3390/jcs10090486

Authors: Ivan Tomasi Luigi Solazzi Xiangwei Liu

Tower cranes are highly vulnerable to seismic excitation owing to their slender geometry and pronounced dynamic behaviour. Although carbon fibre reinforced polymer (CFRP) materials offer significant lightweight potential, and damping devices are widely adopted for seismic protection, their combined application to tower cranes has received limited attention. This study numerically investigates the seismic response of a rearing jib tower crane equipped with a CFRP jib and base joint dampers. A finite element model was developed and analysed under four critical operating configurations through static structural, modal and response spectrum analyses in accordance with the Italian Building Code (NTC 2018). The performance of the CFRP solution was compared with that of a conventional steel crane, while two damper configurations with different stiffness values were also assessed. The proposed lightweight design reduced the total crane mass by 34% and the jib weight by 77%. Compared with the steel configuration, the CFRP solution decreased static displacements by 38–56% and equivalent stresses by 22–44%. Under seismic loading, the adoption of joint dampers reduced the maximum equivalent stress by up to 35%, while increasing structural displacements by 5–19% because of the lower support stiffness. The results demonstrate that combining CFRP lightweight design with seismic damping devices effectively improves the earthquake performance of tower cranes while maintaining structural safety.

Journal of Composites Science doi: 10.3390/jcs10090485

Authors: Saathvika Sivanandam Parthiban Kathirvel

The mounting requirement for sustainable construction materials has augmented the development of geopolymer binders incorporating agricultural wastes. Unlike the previous studies on individual agricultural ashes, this study investigates the viability of combined use of sugarcane bagasse ash (SCBA) and jackfruit leaf ash (JLA) in fly ash-ground granulated blast furnace slag (GGBFS)-based geopolymer binders under ambient curing conditions. Five mixtures with varying proportions of SCBA and JLA were evaluated for their fresh (flow, setting time, fresh density and rise in temperature), hardened (compressive strength and flexural strength) and microstructural characteristics (FESEM-EDS, XRD, FTIR and TG/DTG analyses). The incorporation of 10% SCBA and 10% JLA of the total binder (M3 mixture) was found to produce best performing performance, resulting in a maximum 28-day compressive strength of 64.83 MPa and flexural strength of 7.25 MPa, corresponding to increments of 36.5% and 73.0%, respectively, over the control mix. The formation of a dense reaction matrix along with enhanced geopolymerization and thermal characteristics were also observed for the best performing mixture through microstructural studies. The outcome of this investigation reveals that the utilization of agricultural ashes (SCBA and JLA) can be an efficient supplementary aluminosilicate precursor to develop high-performance geopolymer binders.

Journal of Composites Science doi: 10.3390/jcs10090484

Authors: Lumirca Del Valle Espinoza León Leila Lea Yuan Visconte Ana Lúcia Nazareth da Silva Ana Maria Furtado de Sousa Elen Beatriz Acordi Vasques Pacheco

Polyethylene (PE)-based composites reinforced with lignocellulosic fillers undergo a gradual decline in performance under weathering conditions. This review combines a bibliometric analysis using VOSviewer 1.6.20 with a critical assessment of the literature to examine the weathering behavior of these composites and discuss its implications for the circular economy, particularly with respect to extending service life. The literature shows that mechanical property retention depends primarily on the lignocellulosic filler content (below 50 wt%), fiber-matrix interfacial adhesion, composite microstructure, and environmental exposure conditions. Because lignocellulosic fibers are inherently hydrophilic, water uptake and subsequent microcrack formation can compromise the structural integrity of the composite. Conversely, lignin present in the lignocellulosic reinforcement, coupling agents such as maleic anhydride-grafted polyethylene (PE-g-MA), and ultraviolet (UV) stabilizers such as zinc oxide enhance fiber–matrix adhesion, mitigate photo-oxidative degradation and improve the retention of mechanical properties during weathering. Although the relationship between weathering and the circular economy has rarely been explicitly addressed, the available evidence identifies the material compositions and exposure conditions that favor property retention, thereby supporting longer service life and increasing the potential for circular use of PE-based lignocellulosic composites.

Journal of Composites Science doi: 10.3390/jcs10090483

Authors: Nelson Andrés Guerrero Jimenez York Antony Calvache Tabarez Manuel Alejandro Rojas Manzano Mónica Villaquiran Caicedo

The use of phase change materials (PCMs) in cementitious mortars is a promising strategy for passive thermal regulation and thermal energy storage (TES) in buildings, but its practical implementation remains constrained by PCM leakage and its effects on physical and mechanical performance. This study investigates the use of recycled clay brick waste as a dual-function component in eco-efficient mortars, serving as a partial replacement for fine aggregate and as a porous carrier for paraffin-based PCM. The experimental program comprised three stages: selection of an eco-efficient reference mortar, impregnation of recycled ceramic aggregates using thermal and vacuum-assisted procedures, and evaluation of PCM-modified mortars through fresh-state, physical, mechanical, thermophysical, direct thermal exposure, thermoregulation, and infrared thermography tests. Thermal impregnation at 15 wt% PCM provided the most favorable balance between PCM incorporation and stability against surface accumulation and mass loss and was selected for mortar production. Compared with REFeco, PCM incorporation reduced water absorption by approximately 10% and caused compressive and flexural strength losses below 10%. PCM15 exhibited the most favorable thermophysical balance, increasing volumetric specific heat by 14.9% and thermal inertia by 8.5%, while reducing thermal diffusivity by 10.8%. Under direct flame exposure, PCM25 produced the greatest thermal buffering effect, delaying the attainment of 200 °C on the rear face by approximately 4 min and reducing maximum estimated heat flux by approximately 16% relative to REFeco. Overall, recycled clay brick waste demonstrated potential as a PCM carrier for eco-efficient cementitious mortars with thermal energy storage functionality.

Journal of Composites Science doi: 10.3390/jcs10090482

Authors: Ekaterina Smolskaya Ekaterina Potapova Ivan Korchunov Tatiana Guseva Viktor Guryanov

Cement production is associated with substantial carbon dioxide (CO2) emissions due to the high material and energy intensity of Portland clinker manufacture. Partial clinker replacement with supplementary cementitious materials is one of the most promising strategies for reducing the carbon footprint of cement; however, the thermal activation of aluminosilicate raw materials does not always yield highly reactive products. In this study, a pillaring approach is proposed as a controlled method for modifying the structure of clays and unlocking their latent reactivity. Different clay types—namely, kaolinitic, montmorillonitic, and illite–chlorite clays—were sequentially treated with an aluminum sulfate solution and calcined at 650 °C. Their phase composition and microstructure were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM), while specific surface area was determined by BET analysis and pozzolanic activity. The results showed that pillaring doubled the specific surface area of montmorillonitic (2:1) and illite–chlorite (2:1:1) clays. Replacing 30% of clinker with pillared clays and limestone increased the compressive strength to 86.5 MPa and the flexural strength to 34.6 MPa. The developed low-carbon composite cements also exhibited high durability: the density of the hardened cement mortar increased to 2.410 g/cm3, the strength loss after 200 freeze–thaw cycles decreased to ≤5.5%, and the sulfate resistance coefficient (Ks) increased to 0.98 (with minimal expansion of the samples <0.02%). The proposed approach makes it possible to reduce the carbon footprint of cement by 25–30% while enabling the use of locally available raw materials for the production of competitive low-carbon green cements. Reported reductions of this order are broadly consistent with the known effect of lowering clinker content through supplementary cementitious materials in blended cement systems.

Journal of Composites Science doi: 10.3390/jcs10090481

Authors: Zhiwei Nie Chun Li Zinan Liu Xing Lu Yuhan Ma Helezi Zhou Huamin Zhou

Tool–prepreg friction contributes to process-induced residual stress and distortion in thermoset composite manufacturing, but its variation with the resin cure state remains insufficiently characterized. This study experimentally characterizes the friction response of untreated and post-gel pretreated T800/bismaleimide prepregs using a pull-out apparatus. The effects of slip velocity, temperature, and normal pressure are evaluated, and the measured trends are interpreted using Coulomb-type contact, viscous film shearing, and mixed-lubrication concepts. The friction coefficient of the untreated prepreg increases with the slip velocity and decreases with temperature and pressure, indicating a substantial contribution from viscous resin-film shearing. In contrast, the post-gel pretreated prepreg is nearly insensitive to the slip velocity and pressure, while its friction coefficient increases with temperature, consistent with a predominantly solid-like interfacial response. During a cure cycle, the friction increases slowly at low cure levels and more rapidly during the later stages of curing. The results provide experimental friction data for a high-temperature bismaleimide prepreg system and suggest that the gelation state may serve as a useful reference for distinguishing early- and later-stage interfacial behavior.

Journal of Composites Science doi: 10.3390/jcs10090480

Authors: Fahim Khan Evgenia Dimitriou Miloš Dujović Md Shakil Arman Miladin Radovic Zhijian Pei Stephen Kachur

This study systematically investigates the effects of infiltration temperature (800 and 1000 °C) and magnesium (Mg) content (0, 5, and 10 wt.%) on the density, morphology, and chemical composition of silicon carbide/aluminum-magnesium (SiC/Al–Mg) composites. Poor wettability between molten Al and SiC can restrict the infiltration of porous SiC preforms. Although Mg is commonly used to improve wettability, the combined effects of Mg content and infiltration temperature have not been investigated for composites produced from binder-jetted SiC preforms. Porous SiC preforms were first fabricated by binder jetting of SiC powder and then air-assisted oxidation bonded at 1200 °C for 2 h. The oxidation-bonded preforms were subsequently spontaneously melt infiltrated under an inert atmosphere using either pure Al powder or Al–Mg powder mixtures containing 5 or 10 wt.% Mg. The results showed that composite density increased consistently with increasing Mg content. At 800 °C, the density increased from 1.73 to 2.63 g/cm3 as Mg content increased from 0 to 10 wt.%. Similarly, at 1000 °C, the density increased from 1.80 to 2.73 g/cm3. X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy were used to evaluate phase formation and microstructural features. The results confirmed effective infiltration in Mg-containing samples, while samples without Mg showed limited infiltration at both temperatures. A two-way ANOVA showed that Mg content was the primary factor controlling post-infiltration density, while infiltration temperature had a smaller but statistically significant effect. These findings provide practical guidance for selecting Mg content and infiltration temperature during the fabrication of binder-jetted SiC/Al–Mg composites. Overall, this study highlights the importance of Mg-assisted infiltration for fabricating binder-jetted SiC/Al–Mg composites and provides processing insights relevant to their potential use in aerospace, automotive, and defense applications, subject to further evaluation of their mechanical and functional properties.

Journal of Composites Science doi: 10.3390/jcs10090478

Authors: Lucian Alexander-Roy Meelad Ranaiefar Mrityunjay Singh Michael C. Halbig

Emerging composite materials are expanding the potential of additive manufacturing and enabling applications previously restricted by traditional manufacturing methods through their multi-phase nature and complex internal geometry. Additionally, these materials can be pyrolyzed to create dense metal, ceramic, and glass parts with geometries typically not achievable by traditional processes. Additive manufacturing of borosilicate glass composites can enable new applications in nuclear engineering, astronomy, and bone regrowth therapy. To elucidate the process–parameter relationship of borosilicate–polylactic acid (PLA) composites, mechanical test specimens were fabricated by fused-filament fabrication and compared with a pure PLA baseline. Optical and scanning electron microscopy were conducted to observe the specimen microstructure before and after testing. From the stress–strain curves, the highest compressive yield strength for the composite was 28.22 MPa, and the highest compressive yield strength for PLA was 49.30 MPa. Print orientation was found to benefit the composite material but have a detrimental effect on the pure matrix material. Borosilicate–PLA with 100% infill, 1 shell wall, and layer lines parallel to compression axis had an elastic modulus of 2.66 GPa. Microscopy revealed that lower-modulus composite specimens had the particulates re-distributed within the matrix. Tensile testing was done according to a polymer testing standard, which caused difficulties obtaining consistent fracture within the gauge length.

Journal of Composites Science doi: 10.3390/jcs10090479

Authors: Ahmed A. Ahmed Mahmoud Shakouri Naga Pavan Vaddey

The durability of concrete structures exposed to chlorides is critically governed by chloride ingress, which induces reinforcement corrosion. While ordinary Portland cement (OPC) has been extensively studied, alternative binders such as calcium aluminate cement (CAC) and calcium sulfoaluminate (CSA) cement offer distinct microstructures that may enhance chloride resistance. Understanding how cement type and the water-to-cementitious material ratio (w/cm) influence the apparent chloride diffusion coefficient (Da) is paramount for designing durable infrastructure. This study systematically quantifies the influence of cement type (OPC, CAC, CSA) and w/cm ratio (0.45, 0.55, 0.65) on Da using a full-factorial experimental design and bulk diffusion testing. The results reveal a significant interaction between cement type and w/cm (p < 0.001). OPC exhibits predictable porosity-driven degradation, with Da increasing exponentially from 8.42 × 10−12 to 1.46 × 10−10 m2/s as w/cm increases from 0.45 to 0.65. CAC shows a non-linear response, with optimal performance at w/cm = 0.55 (Da = 2.90 × 10−11 m2/s) due to microstructural refinement from hydrate conversion but suffers severe degradation at w/cm = 0.65. CSA cement is extremely water-sensitive, with Da increasing by an order of magnitude (from ~4 × 10−11 to 3.37 × 10−10 m2/s) at w/cm = 0.65, marking a critical failure threshold. Model fit quality (R2) serves as a leading indicator of microstructural instability, which is corroborated by XRD phase analysis. This study concludes that CSA presents a high risk for field applications with poor w/cm control, while OPC offers more predictable performance, advocating for cement-specific, performance-based specifications beyond traditional OPC-centric limits.

Journal of Composites Science doi: 10.3390/jcs10090477

Authors: Amanda Marcely Reis Camila Monteiro Cholant Lincoln Audrew Cordeiro Patricia Oliveira Schmitt Everton Granemann Souza Chiara das Dores do Nascimento Ivandra Ignês de Santi Darci Alberto Gatto Alexandre Ferreira Galio Caio Gomide Otoni André Luiz Missio

Pectin films are promising renewable materials for biodegradable coatings; however, their high hydrophilicity and limited resistance to ultraviolet (UV) radiation restrict practical applications. This work investigated the influence of kraft lignin (0–5 wt%) on the structure–property relationships of grape-derived pectin films before and after accelerated UV exposure. Structural organization (XRD and FTIR), photostability (CIELAB colorimetry and CIE chromaticity), wettability, water-vapor absorption, surface morphology, soil-burial disintegration, and integrated multifunctional performance were evaluated. Lignin improved resistance to UV-induced structural changes, reducing the relative loss of apparent crystallinity from 52.76% for neat pectin to less than 7% for films containing at least 0.1 wt% lignin, while substantially decreasing UV-induced color changes. Increasing lignin content also reduced surface wettability, water-vapor uptake, and soil-burial mass loss; nevertheless, all formulations exhibited more than 50% mass loss after 120 h of soil burial. Exploratory CRITIC–TOPSIS analysis identified Pec/Lig1 as the highest-performing formulation, whereas Pec/Lig0.1 provided the most compositionally efficient balance among photostability, moisture resistance, structural stability, soil-burial disintegration, and lignin consumption. These findings demonstrate that lignin governs the trade-offs among structural stability, photostability, moisture resistance, soil-burial disintegration, and additive consumption, establishing composition–structure–property–durability relationships that provide practical design guidance for candidate functional coatings for cellulose- and paper-based substrates.

Journal of Composites Science doi: 10.3390/jcs10090476

Authors: Ahmed H. Al-Abdwais Adil K. Al-Tamimi Maher Al-Hamad

Fiber-reinforced polymers (FRPs) are increasingly adopted in structural rehabilitation due to their high strength-to-weight ratio, corrosion resistance, and ease of installation, making them suitable for extending the service life of reinforced concrete (RC) infrastructure. Studies on shear strengthening with CFRP was early focused on externally boning (EB) showed premature delamination between fiber and concrete which limits the bonding strength. Hence, this study experimentally evaluates the shear strengthening behavior of RC beams retrofitted using inside-groove bonded CFRP and hybrid techniques. A total of seven beam specimens with identical geometry, internal reinforcement layout, and concrete strength were fabricated and tested under four-point bending to generate a well-defined shear-critical region. The experimental program focused on directly comparing bonding configurations while also examining the influence of groove depth (10 mm and 15 mm) and steel anchorage for concrete cover on structural response and failure mechanisms. The strengthened specimens achieved ultimate load increases ranging from approximately 10% to 23% relative to the control beam. Variation in groove depth within the investigated range did not significantly influence shear capacity, indicating that moderate groove penetration is sufficient to develop effective mechanical interlock. Steel anchors were introduced to restrain concrete cover separation and improve confinement of the bonded region and substantially increase peak load, it successfully mitigated premature cover delamination near stirrup locations and altered the governing failure mode.

Journal of Composites Science doi: 10.3390/jcs10090475

Authors: Song-Jeng Huang Cheng-Yen Yang Sathiyalingam Kannaiyan

In this study, AZ91 magnesium alloy was used as the matrix material, and Cu powder was added at contents of 1 and 2 wt.% as an alloying addition. The AZ91–Cu alloys were fabricated by gravity casting combined with mechanical stirring. Subsequently, T4 solution treatment and T6 artificial aging treatment were conducted to investigate the effects of Cu content and heat treatment conditions on the microstructure, mechanical properties, and thermal conductivity. The results showed that Cu addition promoted the formation of Al4Cu9 intermetallic compounds. After T4 treatment, part of the β-Mg17Al12 phase dissolved into the α-Mg matrix, resulting in a more homogeneous microstructure. After T6 treatment, fine second phases re-precipitated, leading to a precipitation strengthening effect. In terms of mechanical properties, the T6-treated AZ91-2Cu alloy exhibited the highest hardness, yield strength, and ultimate tensile strength, reaching 83.73 HV, 117.94 MPa, and 173.82 MPa, respectively. In contrast, the highest thermal conductivity of 64.74 W/(m·K) was obtained for the as-cast AZ91-2Cu alloy. Therefore, although T6 aging maximized the mechanical strength, it did not simultaneously maximize thermal conductivity, demonstrating a trade-off between mechanical strengthening and thermal transport performance.

Journal of Composites Science doi: 10.3390/jcs10090474

Authors: Aman Kaushik Afsaneh Rabiei

Novel steel composite metal foams (CMFs) are lightweight materials made from stainless-steel hollow spheres, with entrapped air suspended within the stainless-steel matrix. In this work, the performance of CMF-core front rails, containing steel CMF within an aluminum 6061 alloy double tube, is compared against rectangular high-strength low-alloy (HSLA) 350 steel and double-octagon aluminum 6061 alloy front rails of equivalent masses and lengths. Explicit finite element models of different front rails are subjected to frontal impact with entrapped air within the CMF core modeled using the pneumatic fluid cavity technique. The inclusion of a steel CMF-core within the double-tube structure results in plateauing vehicle deceleration instead of pulsating behavior observed during the buckling of tube-only structures. CMFs containing pressurized air and core–tube interactions enhance the compressive resistance of front rails to prevent localized bucking. The CMF-core front rail increases the accident velocity required to exceed the critical accident severity and head injury criterion (HIC) by 33.73% and 39.50%, respectively, when compared to an equivalent double-octagon front rail and by 31.93% and 48.24%, respectively, when compared to an equivalent rectangular front rail. The research demonstrates that utilizing novel energy-absorbing steel CMFs within automotive front rail structures helps improve occupant safety for crashworthiness applications.

Journal of Composites Science doi: 10.3390/jcs10090473

Authors: Danil W. Boukhvalov Alimzhan Serikbekov Nurlan B. Bakranov Dina I. Bakranova Kazybek Aimaganbetov Tunyk K. Idrissova Murat Rakhimzhanov Abay S. Serikkanov

In this work, we report the fabrication of a relatively efficient, cheap, and stable silicon-based photocatalyst for water purification. Silicon-nickel composites were fabricated by mixing and grinding metallurgical silicon with commercial nickel nanoparticles. Experiments demonstrate a significant improvement in methylene blue degradation under UV—and especially under solar—conditions. About half of the contaminants were degraded after 100 min. Theoretical modeling demonstrates the effects of impurities in subsurface layers on absorbance and on the release of hydroxyl radicals from silicon.

Journal of Composites Science doi: 10.3390/jcs10090472

Authors: Ayaka Matsuo Yui Mitsushima Eiichi Kido Akuto Takagi Tadashi Mizutani

An acylation reaction was performed on the crystalline surface of cellulose in a composite consisting of microfibrillated cellulose (MFC) and hydroxyapatite (HAP) with an inorganic weight fraction of 68%. The composite was acylated using acetic anhydride, propanoic anhydride, and butanoic anhydride in pyridine in the presence of potassium carbonate at 120 °C for 1 h. The formation of ester linkages was confirmed by infrared spectroscopy, and X-ray diffraction analysis showed that the crystalline structure of cellulose was retained after acylation. From the intensity of the carbonyl stretching vibration in the infrared spectra, the degree of substitution of the acetylated sample was estimated to be approximately 0.2. The acylated MFC–HAP composites were uniaxially hot-pressed at 120 °C and 300 MPa, and the resulting molded specimens were subjected to three-point bending tests. A yield point appeared at a bending strain of 1.1–1.4%, followed by plastic deformation and final fracture, indicating that they exhibited ductile fracture. The elastic moduli were 5.9 GPa (acetyl), 7.6 GPa (propanoyl), 7.4 GPa (butanoyl), 3.6 GPa (hexanoyl), and 7.1 GPa (before acylation), indicating that acyl groups with medium chain lengths did not reduce the rigidity of the composites. When the molded specimens were immersed in water at room temperature for 24 h, the water absorption ratios were 29% (acetyl), 24% (propanoyl), 17% (butanoyl), and 18% (hexanoyl), demonstrating that water resistance improved with increasing acyl chain length. In summary, propanoylation and butanoylation improved the water resistance of the composites without compromising their rigidity in the dry state.

Journal of Composites Science doi: 10.3390/jcs10090471

Authors: Ioan Bica Eugen Mircea Anitas Paula Sfirloaga

Honey–gelatin–water composite membranes containing silver microparticles (SmPs) are investigated as soft pressure-responsive materials with potential applications in low-pressure sensing, including biomedical monitoring, and in tunable capacitive components. Three compositions, with nominal volumes of loose SmP powder of up to 3cm3, are prepared to determine how silver loading affects their electrical and apparent compressive response. The membranes are characterized by optical microscopy, XRD, and SEM and are placed between electrodes in a parallel-plate configuration. Capacitance and parallel resistance are measured at 1kHz under applied pressures up to 2.25kPa, and the corresponding admittance components and apparent compressive parameters are calculated from these measurements. It is shown that SmP loading increases the capacitance and reduces the resistance. Between the SmP-free and most highly loaded membranes, the zero-pressure capacitance increases by more than four orders of magnitude, whereas the resistance decreases by approximately a factor of 40. Applied pressure further increases the capacitance and decreases the parallel resistance of all membranes. The apparent strain increases approximately linearly with pressure and is greater in the SmP-loaded membranes, whereas the apparent modulus decreases as the SmP content is increased. The structural and electrical results show that SmP content and the associated heterogeneous microstructure influence both the electrical and apparent compressive response.

Journal of Composites Science doi: 10.3390/jcs10090470

Authors: Ruben I. Erives Antonios Tempelis Philipp Ulrich Haselbach Leon Mishnaevsky

A multiscale computational framework is presented to assess the effect of voids that may arise from a scarf repair and its influence on the post-repair lifetime of wind turbine blades. The approach links a full scale blade model with a detailed repair region model and a microscale representation of polymer adhesives containing voids. Boundary conditions from the global blade model are transferred to the scarf repair model, which subsequently provides input to a microscale representative volume element (RVE) of the adhesive containing voids using the submodelling technique. This RVE is combined with a continuum damage mechanics formulation to simulate high-cycle fatigue and estimate the lifetime for different void contents. The effect of void content resulting from scarf repair is evaluated under both quasi-static and high-cycle fatigue loading, enabling lifetime predictions. In the simulations, it was demonstrated that the lifetime of repaired blade is 4 times lower for the repair with 4% void content as compared with the repair with 1% void content.

Journal of Composites Science doi: 10.3390/jcs10090469

Authors: Kenzhebek Akmalaiuly Nazerke Berdikul Aigerim Tolegenova Assylbek Kabiyev Assel Kanarbay

This study comparatively evaluated lightweight structural and thermal-insulating concrete containing unground rice husk (RH) and commercially supplied ground rice husk (GRH). Two comparative mixture series, one containing unground rice husk (RH) and the other containing ground rice husk (GRH), were produced at four binder levels using cement, fly ash, quartz sand, a polycarboxylate superplasticizer, and an organosilicon water repellent. The study assessed particle characteristics, fresh and hardened density, 28-day compressive strength, thermal conductivity, water absorption, and microstructure. The commercially supplied GRH consisted of fragmented particles with a median size of approximately 0.72 mm, facilitating its incorporation into the granular skeleton. The hardened density remained within 1402–1478 kg/m3, while the average compressive strength increased from 7.38 MPa for RH mixtures to 10.43 MPa for GRH mixtures. Depending on the composition, the GRH mixtures exhibited 26.7–65.0% higher compressive strength than the corresponding RH mixtures at comparable densities. Thermal conductivity remained within the range of 0.36–0.42 W/(m·K), and water absorption varied only from 28.0 to 29.5%. Scanning electron microscopy (SEM) observations revealed more uniform particle distribution, improved particle–matrix contact, and fewer pronounced interfacial defects in GRH composites. The GRH-4 mixture demonstrated the best overall performance, combining a compressive strength of 11.47 MPa, a density of 1462 kg/m3, and a thermal conductivity of 0.42 W/(m·K). These findings show that the investigated GRH-based formulations achieved higher structural efficiency than the corresponding RH-based formulations while largely maintaining their thermal insulation performance; however, the differences reflect the combined effects of particle characteristics, husk dosage, moisture conditions, and associated mixture adjustments.

Journal of Composites Science doi: 10.3390/jcs10090468

Authors: Aleksei V. Shchegolkov Veronica O. Malinkina Ivan A. Komarov Vladimir V. Kaminskii Alexandr V. Shchegolkov

Tungsten trioxide (WO3) and molybdenum trioxide (MoO3) are redox-active Group VI transition-metal oxides widely used in functional thin-film technologies. Many studies have examined single-phase WO3 and MoO3 films. However, WO3/MoO3 nanocomposite thin films and heterostructures have not yet been comprehensively reviewed as interface-engineered platforms for smart and sustainable technologies. This review addresses this gap by analyzing WO3/MoO3 thin-film nanocomposites through the concept of interfacial synergy. Particular attention is paid to the structural complementarity of WO3 and α-MoO3, oxygen nonstoichiometry, mixed W6+/W5+/W4+ and Mo6+/Mo5+/Mo4+ valence states, crystallographic-shear suboxides, W–O–Mo interfaces, and fabrication routes for mixed, graded, and multilayer films. The functional advantages of these systems do not arise from simply combining the two oxides. Instead, they result from charge and oxygen-vacancy redistribution, shortened ion–electron transport pathways, phase stabilization, and the formation of new active sites at interface boundaries. The review also emphasizes the need to distinguish genuine interfacial synergy from apparent improvements caused by surface area, film thickness, porosity, hydration, or measurement conditions. Finally, the review links structural features, defect chemistry, and interface-controlled properties to device-level functionality. This framework highlights promising directions for WO3/MoO3 nanocomposite films in a wide range of smart and sustainable technologies.

Journal of Composites Science doi: 10.3390/jcs10090467

Authors: Mohammed Haji Bestoon Mohammed Faraj

Direct composite veneers provide favorable esthetics and are a one-visit procedure, but are limited by polymerization shrinkage, chipping, and discoloration. Direct–indirect and injectable techniques have been introduced to overcome these limitations. This study compared the shear bond strength, marginal seal, and color stability of these three veneer techniques using two composite materials in each group. We randomly allocated 270 bovine anterior teeth to three veneer groups (n = 90 per group), then divided each group into three testing groups (n = 30 per group); within each testing group, we used two composite materials (15 each). We evaluated the parameters using appropriate statistical tests (p ≤ 0.05). The direct–indirect technique showed the highest shear bond strength and best marginal seal, followed by the injectable and direct techniques (p < 0.0001). The injectable technique demonstrated the greatest color stability, whereas the direct technique showed the highest color change and marginal leakage after aging (p ≤ 0.0001). Composite material had a smaller, less consistent effect than technique overall. These findings indicate that veneer fabrication technique has a greater influence on mechanical and optical outcomes than composite material, with the direct–indirect technique achieving the strongest bond and best marginal seal, and the injectable technique showing superior color stability.

Journal of Composites Science doi: 10.3390/jcs10090466

Authors: Amal Bouhebila Riad Benzaid Javad Shayanfar

This study proposes a generalized mechanics-based analysis-oriented model (AOM) for predicting the complete axial stress–strain response of circular reinforced concrete (RC) columns under partial (discontinuous) FRP–steel confinement. The proposed formulation couples an enhanced dilation model with a unified axial stress–strain relationship to explicitly account for non-uniform lateral expansion between wrapped and unwrapped regions, additional axial deformation developed in unwrapped zones, and FRP–steel confinement interaction through a stiffness-based framework. A spacing-dependent confinement reduction coefficient and a calibrated failure-surface function are further introduced to account for the effects of discontinuous FRP wrapping. To support model development and validation in a concrete-strength range for which experimental data are scarce, axial compression tests were conducted on five circular RC columns, comprising two unconfined reference specimens and three partially FRP-confined specimens with a concrete strength of approximately 50 MPa. The tests showed that FRP confinement increased the axial capacity by up to 365% relative to the reference capacity and increased the post-peak strain ratio to as much as 12.8 times the reference value. At four FRP layers, increasing the strip spacing from 36 to 71 mm reduced the axial capacity by approximately 49%, demonstrating the pronounced influence of confinement discontinuity. Validation against the present tests and independent experimental datasets demonstrated close agreement between the predicted and measured full-range axial stress–strain responses, including the initial response, nonlinear transition, strain-hardening branch, and ultimate response. Across the investigated datasets, the proposed formulation consistently reproduced these response characteristics more accurately than the generalized Teng et al. analysis-oriented model and the ACI 440.2 design-oriented model.

Journal of Composites Science doi: 10.3390/jcs10090465

Authors: Evgenii M. Shcherban’ Sergey A. Stel’makh Alexey N. Beskopylny Diana M. Shakhalieva Andrei Chernil’nik Yuri Pakhomov Natalya Shcherban’ Aleksandr Budovskiy Oxana Ananova Yasin Onuralp Özkılıç

This study focuses on the influence of chemically pure nanodiamonds produced by cavitation synthesis on structure formation and physical and mechanical properties of self-compacting concrete (SCC) using an analytical approach. The objective of this research was to develop a high-performance, self-compacting concrete with enhanced properties suitable for the construction sector. Chemically pure nanodiamonds produced by cavitation synthesis (KHA-HC) were added to SCC at weight percentages of 0%, 0.15%, 0.3%, 0.45%, 0.6%, and 0.75% of the binder mass. Fresh SCC modified with nanodiamonds was evaluated for density and cone spread diameter. Hardened SCC with KHA-HC was tested for density, water absorption, compressive strength, and axial compressive strength. The most effective KHA-HC content was established at 0.3%, correlating with 13.5% greater compressive strength, 15.1% higher axial compressive strength, and 19.6% lower water absorption. Incorporating KHA-HC into SCC resulted in a wider spread cone as the additive content was raised. The microstructure of SCC containing KHA-HC was found to be more homogeneous with a decrease in void content within the cement matrix. Polynomial relationships for changes in SCC properties as a function of nanodiamond content were proposed. The effectiveness of nanodiamond additives for modifying SCC was demonstrated. Highly effective self-compacting concretes with improved performance properties have been developed, which are suitable for construction.

Journal of Composites Science doi: 10.3390/jcs10090464

Authors: Luís Ferro Carla Guimarães Marcos Silva Jorge Neto Máira Braga Ricardo Aguiar

Additive manufacturing enables the fabrication of cellular structures with complex geometries and tunable mechanical response. This study evaluates auxetic-inspired cellular metamaterials manufactured by fused deposition modeling using polylactic acid (PLA) and polyethylene terephthalate glycol (PETG). Standard specimens and three cellular architectures, namely conventional honeycomb, re-entrant honeycomb, and EigenModes, were investigated under tensile, flexural, and compressive loading. Results are reported as the mean ± standard deviation from three specimens per condition. In standard tensile specimens, PLA reached its highest failure load at 60% infill (1034.7 ± 5.8 N), whereas PETG increased with infill density, reaching 919.0 ± 16.5 N at 100% infill. Under flexural loading, the highest standard-specimen values were 38.7 ± 1.2 N for PLA and 20.0 ± 1.0 N for PETG, both at 90% infill. In compression, PLA standard specimens reached 98,645 ± 448 N at 100% infill, while PETG reached 47,292 ± 16,139 N. For cellular compression specimens manufactured at 90% infill, PLA showed higher failure load values than PETG in all evaluated geometries, with re-entrant honeycomb and EigenModes reaching 9424 ± 1327 N and 9172 ± 157 N, respectively. Scanning electron microscopy indicated brittle fracture and interlayer microcracking in PLA, while PETG showed greater deformation tolerance around voids and local discontinuities. Overall, the mechanical response depended on polymer behavior, loading mode, infill density, and cellular topology. Since Poisson’s ratio was not directly measured, auxetic-inspired metamaterial refers to architectures commonly associated with auxetic behavior in the literature.

Journal of Composites Science doi: 10.3390/jcs10090463

Authors: Aijun Chen Yifan Zhou Junhua Chen

A sustainable controlled low-strength material (CLSM) was developed using ground granulated blast-furnace slag, steel slag, and flue gas desulfurization gypsum in combination with cement to synergistically utilize engineering excavated soil and industrial solid wastes for stabilizing low liquid limit clay. However, the long-term durability evolution of this material under harsh and coupled environmental conditions—particularly freeze–thaw cycles, wet–dry cycles, and prolonged drying—has not been systematically investigated. In this study, systematic freeze–thaw cycling (up to 11 cycles), wet–dry cycling (up to 11 cycles), and natural drying (until mass stabilization) tests were conducted on specimens with binder contents ranging from 8% to 16%. The evolution of mechanical performance was evaluated via unconfined compressive strength (UCS) tests, while microstructural changes were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results revealed a distinctive “S-shaped” fluctuation in UCS under freeze–thaw cycles. High-binder (16%) specimens maintained strengths of 1783–2395 kPa with intact surfaces and no visible cracking—significantly outperforming low-binder specimens. Under wet–dry cycles, strength initially increased after the first cycle and then declined progressively, with the lowest strength loss observed at 10% binder content. During drying, both water loss rate and drying shrinkage strain decreased with increasing binder content: from 8% to 16% binder, the water loss rate dropped from 34.16% to 29.03%. Microstructural analysis revealed that higher binder content promoted the formation of a dense, interwoven network of C–S–H gel and ettringite, which effectively filled intergranular pores and encapsulated soil particles, thereby enhancing macroscopic durability. This study provides a sustainable material solution for utilizing industrial solid wastes in the stabilization of low liquid limit clay for CLSM applications under severe environmental conditions, supporting the broader adoption of waste-to-resource strategies in construction engineering.

Journal of Composites Science doi: 10.3390/jcs10090462

Authors: Isuri Tamura Amarasinghe Yi Qian Tharaka Gunawardena Priyan Mendis Benoit Belleville

The utilisation of wood-processing residues in particleboard production provides an opportunity to improve resource efficiency. However, limited research has systematically examined the combined influence of material characteristics and fabrication parameters on panel performance. This study investigates the joint influence of particle mix, resin content and processing method on the performance of particleboards manufactured from radiata pine (Pinus radiata) wood residues. Single-layer panels were fabricated using coarse particles, thin particles, and a thin–fine particle blend at three resin contents via dry and water-conditioned fabrication methods, targeting a constant density of 600 kg/m3. Panels were evaluated for modulus of rupture (MOR), modulus of elasticity (MOE), thickness swelling (TS) and water absorption (WA). The results revealed statistically significant interaction effects among the factors, with particle geometry primarily governing bending performance, and fabrication route exerting the strongest influence on dimensional stability. Thin-particle panels exhibited the highest bending performance, with the 12 wt.% dry-fabrication method achieving an average MOE of 1862 MPa and MOR of 14.65 MPa. In contrast, fine-particle incorporation reduced bending performance but improved dimensional stability, with micro-CT analysis showing lower porosity and smaller pore features in the selected fines-containing panel, reaching a minimum porosity of 3.6%. Overall, the findings demonstrate that coordinated optimisation of material composition and processing parameters can enhance the performance of residue-based particleboards.

Journal of Composites Science doi: 10.3390/jcs10090461

Authors: Nisha Shetty Chethan K. N. Sampath Suranjan Salins Laxmikant G Keni Gowrishankar Mandya Channegowda Pradeep Sherigar Sudhir Jain Prathik

Oral diseases impact approximately 3.5 billion individuals globally, often leading to the loss or damage of periodontal, alveolar bone, dentin-pulp, or oral soft tissues. Consequently, dental tissue engineering necessitates scaffolds that can simultaneously offer a three-dimensional extracellular matrix-like microenvironment conducive to cell adhesion, migration, and differentiation. These scaffolds must also maintain spatial and mechanical integrity during the healing process and degrade at a rate that aligns with new tissue formation. Conventional biomaterials frequently fail to meet all these criteria. Natural polymers, such as collagen, provide cell-recognition cues and support cellular responses but may lose mechanical integrity before regeneration is complete. In contrast, many synthetic polymer barriers maintain structural stability and offer adjustable degradation rates but exhibit limited intrinsic bioactivity. Electrospinning offers a method to integrate these complementary characteristics into fibrous scaffolds with high surface areas that replicate essential structural aspects of the native extracellular matrix. This structure provides cells with a greater surface area for adhesion, migration, and remodeling than cast films or solid scaffolds. This review brings together the electrospinning literature related to dental applications. It begins with the basics of the process, including Taylor cone formation, jet whipping, and the solution, instrument, and environmental factors that influence fiber diameter and morphology, as well as variations such as coaxial, emulsion, melt electrowriting, and needleless electrospinning. It then explores the natural, synthetic, and composite polymer systems used to produce dental nanofibers and their applications in periodontal regeneration, alveolar bone repair, dentin-pulp regeneration, antibacterial and drug delivery functions, and oral wound healing. The obstacles, such as low production throughput, inconsistent sterilization and testing protocols, and the scarcity of large-animal and human trials, that still hinder the transition of laboratory-scale electrospun scaffolds to regular use in dental practice are discussed, and the research directions most likely to bridge this gap are highlighted.

Journal of Composites Science doi: 10.3390/jcs10090460

Authors: Rafah Rasheed Abdulmajeed

The use of industrial waste materials as partial cement replacement has become a popular topic for research to effectively reduce cement consumption, lower CO2 emissions and improve the sustainability of concrete production. In addition to environmental benefits, these materials have been shown to modify the mechanical and durability performance of concrete positively when used at appropriate amounts. In this study, an investigation was carried out to evaluate the effects of cement kiln dust (CKD) and ground granulated blast-furnace slag (GGBFS) as partial cement replacement at ratios ranging from 0% to 50% on the physical, mechanical, and durability behavior of the modified pervious concrete compared to the control one. The analysis proves that CKD reaches its optimum performance at relatively low replacement rates (from 5 to 10%), which results in increased early compressive strength up to 14.28 MPa (+19.3%) and tensile strength to 2.90 MPa (+55.9%). This is due to a greater particle packing and rapid hydration of cementitious materials. Oppositely, despite the decrease in compressive and flexural strength of concrete at 50% replacement ratio of cement by CKD (6.24 MPa and 1.45 MPa), GGBFS significantly increases the long-term durability. At a replacement ratio equal to 50%, GGBFS leads to permeability of 18.01 mm/s (−57.0%), water absorption of 2.53% (−56.0%), and freeze–thaw weight loss of 5.58%. Overall, low ratios (≤20%) of CKD and GGBFS are preferable for non-structural applications, as they provide performable permeability with enough mechanical and durability capacity.

Journal of Composites Science doi: 10.3390/jcs10090459

Authors: Jiaqi Huang Guanghong Fan Yunxia Chen

Thermoplastic composites offer substantial lightweighting potential for body-in-white (BIW). However, the application of long-fibre-reinforced thermoplastic direct processing (LFT-D) to deep-drawn rear-body parts remains largely unexplored. This work presents the first documented LFT-D glass-fibre/polypropylene spare wheel well for a production electric vehicle, validated under a full vehicle-level durability programme. Fibre orientation was characterised by X-ray computed tomography, and both isotropic and orthotropic finite element models were built. Prototypes passed six component-level validation tests: stiffness, constrained modal, thermal cycling, low-temperature impact, stone impact, and a 7000 km road simulation; the orthotropic model, validated against these tests, reduced the first natural frequency prediction error to 3.9%. No structural damage occurred in any test. The composite part achieved 35% mass saving at component level and 54% at system level versus the steel assembly. Adding up to 20 wt% regrind retained >89% of virgin tensile strength (95% confidence interval [CI] lower bound: 89.2%) and >92% of impact strength, and cradle-to-gate CO2 emissions dropped by 42%. These results show that LFT-D can be applied to large, structurally critical BIW components, delivering both lightweighting and closed-loop recyclability for electric vehicles.

Journal of Composites Science doi: 10.3390/jcs10090458

Authors: Jinshui Yang Tuo Yan Mingming Nie Dingding Chen Changping Yin Suli Xing Chaoyi Peng

This work aims to uncover the thermochemical thickness effect mechanism for thick-section composites manufactured via the vacuum infusion molding process (VIMP). Taking the wind turbine blade grade RIMR135/RIMH137 epoxy system as the material subject, dynamic and isothermal curing kinetics were characterized by differential scanning calorimetry (DSC). Autocatalytic and modified autocatalytic models were constructed to describe the respective curing behaviors. Experimental measurements together with finite element analysis were performed to clarify the influences of component thickness and geometric dimensions on curing thermochemistry. The reference pre-curing, curing and post-curing temperatures of the resin were 45 ± 5 °C, 98 ± 5 °C and 134 ± 5 °C. Obvious temperature overshoot arose at the section centre, yielding a maximum internal temperature difference of 30 °C and a 10% discrepancy in the degree of cure. Temperature- and cure degree-related gradients increased linearly with component thickness and volume. This research supplies theoretical support for the process optimization of large, thick-walled composite parts.

Journal of Composites Science doi: 10.3390/jcs10090457

Authors: Abeer A. Al Dalou Ayman N. Ababneh

Steel reinforcement corrosion is a major cause of reduced service life in reinforced concrete structures, making the accurate prediction of corrosion-induced concrete cover cracking essential. This study presents an analytical model for predicting the cracking time of concrete cover due to reinforcement corrosion. The model was developed based on the biaxial stress state induced by expansive corrosion products. Because the cracking criterion is defined in terms of biaxial stress, the model incorporates both the compressive and tensile strengths of concrete. The resulting biaxial stress state was used to determine the critical corrosion pressure at the onset of cracking. The model also accounts for the portion of corrosion products that accumulates in the porous zone and within radial cracks. The model predictions were validated against experimental data and compared with those of existing models reported in the literature, demonstrating improved accuracy and reliability. A parametric study was performed to investigate the effects of various parameters, including concrete compressive strength, tensile strength, cover depth, reinforcement diameter, and corrosion current density. The results showed that concrete compressive strength, tensile strength, cover depth, and corrosion current density significantly affect the predicted cracking time.

Journal of Composites Science doi: 10.3390/jcs10090456

Authors: Rayeh Nasr Al-Dala’ien Mohammed Jalal Al-Ezzi Jihad E. AlQasimi

Hollow filament-wound glass fiber-reinforced polymer (GFRP) tubes are known for their high specific strength, corrosion resistance, and structural efficiency. The nonlinear flexural response of these structures is controlled by the interaction of material and stability mechanisms, which are not well-captured by traditional linear sectional approaches. In this paper, a nonlinear sectional analytical model is proposed to determine the flexural response and the corresponding failure modes of hollow filament-wound GFRP tubes subjected to monotonic four-point bending. The formulation combines Euler–Bernoulli beam kinematics, layered numerical integration of the annular cross-section, asymmetric nonlinear tensile and compressive constitutive relations, iterative neutral-axis equilibrium, tangent-stiffness degradation, and compression-side local shell-buckling assessment in a curvature-controlled incremental solution routine. This framework captures progressive stress redistribution, neutral-axis migration, degradation of flexural rigidity and transition from material-controlled compression failure to local shell instability. Validation was performed against experimental results for five filament-wound glass/vinylester tube configurations with nominal ±55° winding and diameter-to-thickness ratios, D/t, ranging approximately from 20 to 75. The predicted load–deflection and moment–curvature responses were in good agreement with the experimental measurements with mean errors of about 1.6% for peak load, 1.8% for ultimate bending moment and 2.4% for peak curvature. The model also reproduces the experimentally observed governing failure mechanisms over the investigated configurations. The convergence study with sectional discretization showed that 200 integration layers provide a good compromise between numerical accuracy and computational efficiency, with less than 1% variation compared to the refined 500-layer reference solution. The proposed reduced-order formulation has low computational cost in the present implementation and provides a direct physical interpretation of the evolving sectional response. Because a directly comparable finite-element runtime was not reported for the benchmark model, no quantitative FE speed-up factor is claimed. Thus, the proposed framework provides an efficient analytical tool for the nonlinear flexural evaluation of hollow filament-wound GFRP tubes in the validated geometric, loading and laminate domain.

Journal of Composites Science doi: 10.3390/jcs10090455

Authors: Larisa-Anda Stroe Daniel-Eugeniu Crunteanu Casandra Venera Pietreanu Mihail Botan George Catalin Cristea Gabriela-Liliana Stroe

Carbon-fiber-reinforced polymer (CFRP) composites are widely used in lightweight aerospace structures because their mechanical performance can be adapted to different structural requirements through appropriate manufacturing conditions. This study investigates the influence of curing temperature applied using temperature-controlled heated molds on the mechanical and thermo-mechanical behavior of vacuum-infused CFRP laminates manufactured with an IN2 epoxy infusion resin. Laminates were cured at room temperature (25 °C) and at 40, 50, 60, and 70 °C using heated molds. Their performance was evaluated by tensile testing, three-point bending, and heat deflection temperature (HDT) measurements. The highest tensile strength (675.06 MPa) was obtained for laminates cured at 40 °C, whereas increasing the curing temperature beyond this value did not provide further improvement in tensile performance. The highest flexural stress at the first peak (983.36 MPa) and flexural modulus (67.17 GPa) were obtained for laminates cured at 70 °C, while the highest energy absorption during bending (0.57 J) was measured for laminates cured at 40 °C. The HDT increased from 59.77 °C for room-temperature curing to 87.60 °C for laminates cured at 70 °C, indicating improved thermo-mechanical stability with increasing curing temperature. The results indicate that no single curing temperature simultaneously maximized the tensile, flexural, and thermo-mechanical properties. Instead, the optimum curing temperature depended on the specific mechanical and thermo-mechanical requirements of the intended application. The results further indicate that controlling the temperature of heated molds during manufacturing provided a practical approach for tailoring the mechanical and thermo-mechanical performance of CFRP laminates without modifying the reinforcement architecture, laminate stacking sequence, or constituent materials.

Journal of Composites Science doi: 10.3390/jcs10090454

Authors: Hyunjin Cho Jiadeng Zhu

Carbon fiber-reinforced polymer (CFRP) composites are widely used in high-performance engineering applications because they combine low weight with high specific strength and stiffness, dimensional stability, and a tailorable structural response [...]

Journal of Composites Science doi: 10.3390/jcs10090453

Authors: Phi Hoang Trinh Dinh Van Thanh

This study presents a hierarchical multiscale homogenization framework to evaluate the thermo-mechanical performance of hybrid aluminum matrix composites (HAMCs) reinforced with Silicon Carbide (SiC) particles and Graphite (Gr) for lightweight automotive brake discs. A sequential homogenization strategy was employed in which an Aluminum–5 vol.% Graphite hybrid matrix was first established using the Rule of Mixtures and the Halpin–Tsai model, followed by the incorporation of 5–25 vol.% SiC using the Mori–Tanaka homogenization scheme. Three-dimensional Representative Volume Elements (RVEs) with periodic boundary conditions were generated in ANSYS Material Designer(v2025) to determine the effective mechanical properties, while the effective thermal properties were evaluated using the homogenization formulations described in the methodology. The resulting effective material properties were subsequently used in a macro-scale finite element model of a ventilated brake disc for coupled thermo-structural analysis. The results show that increasing the SiC content significantly enhances the effective elastic stiffness while maintaining a stable thermo-mechanical response with marginal variations in global deformation. Compared with conventional gray cast iron, the proposed hybrid composites reduced the maximum operating temperature from 322.77 °C to approximately 280 °C and decreased the maximum total deformation by approximately 45% under identical loading conditions. The proposed framework establishes a computational link between composite microstructure and component-level performance, providing an efficient numerical methodology for the design and optimization of lightweight automotive brake discs.

Journal of Composites Science doi: 10.3390/jcs10090452

Authors: Joaquín Alejandro Hernández Fernández Juan Jose Carrascal Jose Alfonso Prieto Palomo

Hydrophilic polymer films containing environment-sensitive chromophores are useful model systems for examining optical responses in polar matrices. In this study, chitosan/poly(vinyl alcohol) (CS–PVA) films containing low nominal loadings of 3-hydroxyflavone (3HF; 0.05–0.20 wt.%) were prepared by solution casting and characterized in terms of macroscopic appearance, thickness, ultraviolet–visible (UV–Vis) response before and after ultraviolet-A (UV-A) exposure, Fourier-transform infrared spectroscopy with attenuated total reflectance (FTIR-ATR), and water-related behavior. All formulations produced continuous and macroscopically translucent films without visible precipitation or phase separation. Film thickness varied substantially among formulations (0.100–0.168 mm), requiring cautious interpretation of raw transmittance data. Before UV-A exposure, the thickness-normalized apparent attenuation coefficient at 365 nm (α_app,365) ranged from 23.84 to 121.74 cm−1 and followed a non-monotonic order: CS–PVA–3HF-0.05 > CS–PVA–3HF-0.20 > CS–PVA–3HF-0.10 > CS–PVA. UV-A exposure for 120 min produced formulation-dependent changes in optical response, with no common concentration-dependent trend. FTIR-ATR spectra showed relatively small variations in the O–H/N–H, carbonyl/amide, and C–O regions; because several band displacements were comparable to the instrumental resolution, these changes were interpreted as variations in the local vibrational environment rather than direct evidence of hydrogen-bond-network restructuring. Water-contact measurements revealed very high apparent water uptake together with post-immersion dry-mass losses above 94%, demonstrating limited aqueous stability. Density functional theory (DFT) calculations combined with Multiwfn wavefunction analysis on isolated 3HF, a three-unit poly(vinyl alcohol) oligomer (PVA3), and a two-unit chitosan oligomer (CS2) described their intrinsic electronic features but did not establish intermolecular complex formation or directly explain the experimental responses. Overall, the results provide a descriptive characterization of the optical and water-related behavior of 3HF-containing CS–PVA films while emphasizing the influence of film geometry and the limitations associated with nominal, rather than analytically verified, chromophore loading and isolated-component computational models.

Journal of Composites Science doi: 10.3390/jcs10090451

Authors: Markus Haag Mariagrazia Troia Patrick Delfs Pascal Holste Dhia Ben Salem Lea Senneka Oliver I. Strube Deniz Yesilyurt Andreas Schulz Matthias Walker Christoph Greb Thomas Gries

Glass fiber-reinforced plastics (GFRPs) rely on strong fiber–matrix adhesion to achieve optimal mechanical performance. However, conventional sizing systems provide only partial surface coverage and may limit interfacial bonding. The current study investigates atmospheric-pressure plasma-enhanced chemical vapor deposition (APECVD) as an alternative approach for depositing adhesion-promoting plasma coatings on glass fibers intended for epoxy-based composites. Organosilane precursors were deposited using an atmospheric plasma jet under different operating conditions, and the chemical composition and the morphology of the resulting plasma coatings were extensively characterized. Adhesion performance was evaluated by pull-off tests on glass sheets and pull-out tests on glass fibers embedded in epoxy resin. Results show that the plasma coatings provide complete surface coverage and present a tunable chemistry containing several adhesion-promoting functional groups, including silanol and amine-containing species. Pull-off tests on glass sheets demonstrate adhesion improvements of at least 68% compared with untreated glass. In pull-out tests, plasma-coated glass fibers achieved interfacial shear strengths up to 102.9% higher than untreated fibers and 24.4% higher than an industrial reference material. These results demonstrate how atmospheric plasma polymerization can produce effective adhesion-promoting coatings on glass surfaces, thus offering a promising and industrially scalable alternative to conventional adhesion promoters for epoxy-based GFRPs.

Journal of Composites Science doi: 10.3390/jcs10090450

Authors: Nikita P. Ivanov Oleg O. Shichalin Alexander Yu. Mayor Alexander L. Trigub Alexander V. Syuy Vitaliy Yu. Mayorov Vladimir L. Rastorguev Kirill V. Barkhudarov Victoria V. Provatorova Valeriy I. Razov Anton V. Shurygin Igor Yu. Buravlev Sergey S. Golik Sofia B. Yarusova Evgeniy K. Papynov Ivan G. Tananaev

Uranium separation from aqueous media remains a critical challenge at the intersection of nuclear fuel cycle efficiency and environmental safety. Layered double hydroxides (LDHs) are promising adsorbents for U(VI) removal and serve as versatile inorganic matrices for the design of nanocomposite sorbents. However, the influence of their key structural parameter, Me2+/Me3+ cationic ratio, on sorption performance and composite functionality remains insufficiently explored. This study investigates how the Zn2+/Al3+ ratio governs the structure, sorption kinetics, and U(VI) uptake mechanisms of Zn-Al LDH. Characterization by XRD, TEM, XPS, XAFS, cryogenic laser-induced fluorescence spectroscopy, Raman, and positron annihilation spectroscopy revealed that increasing Al3+ content up to the optimal ratio of 2/1 enhances sorption capacity through increased positive charge density, reaching maximum static (47.2 mg/g) and dynamic (17.05 mg/g) capacities. EXAFS and fluorescence spectroscopy demonstrate that U(VI) adsorption at pH 4.0 proceeds via inner-sphere complexation involving mononuclear uranyl carbonate/hydroxyl species (UO2(CO3)22−, UO2(CO3)34−, UO2(OH)n(2−n)) and polynuclear complexes, predominantly (UO2)2(CO3)(OH)3−. Further increase to Zn/Al = 1/1 induced mesopore narrowing and inhibited diffusion, drastically decreasing dynamic performance. These findings establish the Zn/Al ratio as a key parameter governing LDH sorption efficiency and provide a mechanistic basis for the rational design of LDH-based composite sorbents.

Journal of Composites Science doi: 10.3390/jcs10090449

Authors: Ajitanshu Vedrtnam Kishor Kalauni Shashikant Chaturvedi Martin T. Palou

This study presents a physics-informed, climate-responsive model for predicting carbonation depth and compressive strength degradation in conventional and sustainable cementitious composites under real environmental exposure. The Semi-Theoretical Predictive Degradation (STPD) model couples hourly temperature, relative humidity, and CO2 concentration data with two-dimensional diffusion–reaction equations implemented in FEniCS. The model accounts for humidity-sensitive diffusivity, temperature-activated carbonation kinetics, and CO2 consumption via Langmuir decay. Experimental validation was performed on ordinary Portland cement (OPC) concrete specimens exposed for 30 days to climate profiles representative of Portugal (average 14.2 °C, RH 74%, CO2 ~417 ppm) and Slovakia (average 4.7 °C, RH 80%, CO2 ~414 ppm). Carbonation depth increased from 0 to 0.30 mm in Portugal and up to 0.15 mm in Slovakia, with corresponding predicted reductions in compressive strength relative to the corresponding uncarbonated reference of up to 25% and 14%, respectively. The STPD model accurately reproduced these trends, achieving RMSE values of 0.008 mm for carbonation depth and 1.55 MPa for compressive strength in OPC concrete. To assess the broader applicability of the framework, simulations were extended to fly ash/slag-blended, geopolymer, and biochar-containing concretes using material-specific parameters. Among the simulated systems, geopolymer concrete showed the highest predicted durability, with carbonation depths below 1 mm and strength loss below 10%. A degradation index combining carbonation depth and strength loss mapped high-risk zones near the exposed surface, particularly under warm and fluctuating climatic conditions. The model provides a transferable framework for climate-informed durability assessment, material selection, and the design of sustainable cementitious composites.