Search Results (930)

The integration of zeolitic imidazolate framework-8 (ZIF-8) into polymer matrices has created a versatile class of nanocomposites with potential applications in gas separation, water purification, food packaging, sensing, catalysis, energy systems, and environmental remediation. However, their performance is governed by complex and strongly coupled variables, including ZIF-8 particle size, morphology, defect density, surface chemistry, filler loading, polymer compatibility, interfacial adhesion, dispersion state, and processing conditions. To organize this complexity, the review introduces a hierarchical design framework that distinguishes controllable synthesis and processing inputs, experimentally measurable intermediate material states, and condition-dependent performance outputs, thereby providing a structured basis for machine-learning-ready data representation. Conventional trial-and-error approaches are therefore often inefficient and provide limited capacity to identify transferable structure–processing–property relationships. This review examines the emerging role of machine learning (ML) in the rational design and optimization of ZIF-8/polymer nanocomposites for sustainable applications. Particular attention is given to the construction of material descriptors, selection of predictive algorithms, interpretation of feature importance, optimization of synthesis and processing parameters, and prediction of mechanical, thermal, barrier, transport, adsorption, catalytic, and antimicrobial properties. The review further discusses how supervised learning, explainable artificial intelligence, active learning, Bayesian optimization, transfer learning, and physics-informed models can support material screening and multi-objective optimization across performance, cost, energy consumption, environmental impact, and end-of-life considerations. Current limitations, including small and heterogeneous datasets, inconsistent reporting, insufficient negative results, limited model interpretability, and weak experimental validation, are critically evaluated. A future framework is proposed that integrates standardized databases, high-throughput experimentation, multiscale characterization, life-cycle indicators, uncertainty quantification, and closed-loop machine learning. Such an approach could accelerate the transition from empirical formulation toward data-driven, interpretable, and sustainability-oriented design of ZIF-8/polymer nanocomposites. Full article

Objective: This study aimed to evaluate the long-term degradation behavior, biostimulatory effects, and biocompatibility of a novel poly-L-lactic acid-block-polyethylene glycol/hyaluronic acid (PLLA–b–PEG/HA) composite filler for soft tissue augmentation. Methods: PLLA–b–PEG/HA microsphere properties were characterized via scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), nuclear magnetic resonance hydrogen spectroscopy (¹H NMR), thermogravimetry (TG) and differential scanning calorimetry (DSC). A 104-week in vivo rabbit model was established to systematically observe filler degradation and tissue responses. Ultrasound monitoring, histological staining, ELISA and RT-PCR were performed to assess volumetric changes, inflammatory reactions and collagen synthesis-related signaling. Results: Physicochemical property tests demonstrated that PLLA–b–PEG retains the fundamental physicochemical properties of pristine PLLA while exhibiting enhanced hydrophilicity. B-ultrasound demonstrated a presented uniform in vivo distribution without displacement or diffusion over time, confirming steady and predictable degradation. SEM verified progressive morphological degradation and porous evolution of the microspheres. The filler induced a mild, balanced inflammatory microenvironment with early expression of both pro-inflammatory (IL-12, TNF-α) and anti-inflammatory (IL-4) cytokines, which resolved gradually over time. Sustained TGF-β upregulation persisted throughout the 104-week observation period, driving continuous neocollagenesis and prominent neoelastogenesis, thereby achieving favorable and long-term tissue remodeling with excellent biocompatibility. Conclusions: The PLLA–b–PEG/HA composite filler exhibits controllable degradation properties and homeostatic regulatory effects, along with outstanding long-term biosafety and tissue integration capacity. As an ideal biostimulatory filler for soft tissue augmentation, it can effectively facilitate the regeneration of high-quality functional extracellular matrix rich in collagen fibers and elastic fibers, and holds promising clinical prospects for natural and long-lasting soft tissue filling applications. Full article

While the individual effects of sustainable fillers on cementitious systems are widely known, their combined tribological and fracture behaviors within a polymer concrete matrix remain largely unexplored. Addressing this gap, this study experimentally investigates the physical, mechanical, and tribological characteristics of polyester-based polymer concrete (PC). In addition to reference specimens produced with polyester resin and silica sand, modified mixtures were developed by replacing the silica sand with ground granulated blast-furnace slag (GGBS) and recycled waste concrete aggregate (WC) at various substitution ratios (0%, 5%, 10%, 15%, 20%, and 25%). To evaluate the performance of the developed PCs, parameters including unit weight, water absorption capacity, flexural and compressive strengths, Shore D hardness, surface roughness, acid resistance, Bohme abrasion resistance, and fracture energy were analyzed. Furthermore, temperature variations on the friction surfaces were monitored in real time using a thermal camera during the Bohme abrasion tests. To elucidate the fracture mechanisms, the fractured surfaces were examined via digital microscopy. The quantitative findings indicate that a 25% GGBS replacement optimizes mechanical performance, increasing the compressive and flexural strengths by 21.2% (108.30 MPa) and 30.6% (35.29 MPa), respectively, alongside a 27% improvement in Bohme abrasion resistance. However, this modification significantly increases material brittleness, reducing the fracture energy by 53.3% compared to the reference. Conversely, although incorporating WC offers sustainability advantages, it limits mechanical performance, leading to decreases of up to 9.9% (80.46 MPa) in compressive strength and 15% (22.97 MPa) in flexural strength at a 20% substitution rate. Regarding fracture energy, while the W20 series absorbed more energy than the B25 series, it still remained 47.8% lower than the reference. Additionally, the GGBS-incorporated series demonstrated higher susceptibility to sulfuric acid attack compared to the WC-incorporated series. Full article

To reduce the high post-harvest losses of perishable fruits due to fungal spoilage, a novel, self-healing, active multilayer coating based on green polymer chemistry was developed. The system was constructed by the layer-by-layer technique from a dual-modified pullulan polyelectrolyte pair—pullulan maleate and enzymatically derived pullulan betaine with incorporation of β-cyclodextrin/neem oil inclusion complex (β-CD/NO). SEM and DSC analyses confirmed the successful formation of the complex and the structural transition to a rough topography. Due to strong interlayer electrostatic interactions and β-CD as a rigid filler, the multilayer films with the active complex achieved the highest tensile strength of 1.30 ± 0.61 MPa (up to 4× increased in comparison to the monolayer films), with a decrease in elasticity to 10.84%. Additionally, water vapor permeability values were reduced by 22%–28% compared to related biomatrices, while rapid, water-activated self-healing successfully repaired physical film damage. In vitro testing against Candida albicans showed a pronounced synergistic effect with a zone of inhibition of 16.5 ± 1.1 mm for the active formulation. During seven-day in vivo testing on fresh figs, the active coating effectively suppressed yeast proliferation at room temperature (maintaining levels at 2.1 log CFU/g versus 7.1 in untreated figs) and under refrigerated conditions. This innovative system represents a highly promising and sustainable platform for active food packaging. Full article

Cornhusks are widely employed as reinforcing fillers in biocomposite fabrication, where conventional manufacturing processes rely on petroleum-derived resins or adhesives. This reliance not only poses substantial risks to human health and ecological environments, but also leads to the unsatisfactory mechanical performance of the final products. Developing a feasible strategy to eliminate petroleum-based binders while simultaneously enhancing the mechanical strength of the biocomposites remains a challenge. In this paper, we present an adhesive-free approach to produce high-performance, sustainable biomass structural materials directly from raw cornhusks, without prior pulverization, via a combined alkaline retting and hot-pressing treatment. Benefiting from the synergistic effects of highly aligned cellulose fibers and a densely compacted multi-layer structure, the resulting structural material exhibits a tensile strength of 136 MPa and a flexural strength of 127 MPa. These values are higher than those of conventional density fiberboards (approximately 20 MPa and 40 MPa). After 72 h of water immersion, the material shows a water absorption rate of 38% and a thickness swelling rate of 16%, both of which are lower than the corresponding parameters of traditional density fiberboards (around 60% and 20%). Its initial thermal degradation temperature reaches 251 °C, showing good thermal stability. Furthermore, the as-fabricated cornhusk-based structural material, which combines high mechanical strength, water resistance, and thermal resistance, exhibits zero formaldehyde emissions. It can serve as a promising alternative to traditional petroleum-bonded biomass density boards, for applications in furniture manufacturing and interior decoration. Full article

Chitosan-based films and nanocomposites have attracted growing attention as renewable, biodegradable, and chemically adaptable materials for sustainable electronics. This systematic review synthesizes evidence on chitosan-containing functional films, membranes, polymer electrolytes, dielectric substrates, optoelectronic nanocomposites, electrochemical sensors, impedance sensors, and smart-device interfaces. This review adopts a structure–property–function perspective, examining molecular interactions, crystallinity, amorphous fraction, morphology, filler dispersion, processing routes, and interfacial architecture in relation to optical, electrical, dielectric, electrochemical, and sensing performance. The literature was identified using Scopus-oriented Boolean searches combining chitosan/chitin terms with thin-film or membrane descriptors, electronic-function terms, and structure–property terminology. Relevant studies were grouped into four themes: structural engineering and processing, dielectric/electrical/impedance properties, optoelectronic and band-gap engineering, and electrochemical/impedance-sensing applications. The synthesis shows that chitosan becomes electronically functional when its semi-crystalline, hydrogen-bonded matrix is modified through salt doping, plasticization, blending, conductive polymers, carbon materials, metal oxides, metal–organic frameworks, or noble metal nanoparticles. Reported advances include ionic conductivities up to 10⁻³ S/cm, improved dielectric behavior, band-gap reduction, and low detection limits. However, inconsistent reporting of material source, molecular weight, degree of deacetylation, film thickness, humidity, stability, and sustainability metrics limits comparability. Full article

The increasing accumulation of mine tailings has motivated the development of sustainable strategies for their reuse within the framework of the circular economy. This study evaluates the mechanical performance of four laboratory-cast concrete mixtures: a reference mixture, a mixture in which copper tailings were incorporated at 8% of the base mixture mass to replace an equivalent mass of natural coarse sand, and two tailings-based mixtures reinforced with 0.4% and 1.2% steel fibers. Their compressive strength and elastic modulus were evaluated after 7, 14, 28, and 100 days of curing to assess the mechanical performance of the proposed mixtures and their potential relevance for underground mining support applications. The results showed that after 100 days, the 8% copper tailings mixture reached a compressive strength of 41.6 MPa, compared with 39.6 MPa for the conventional mixture. The addition of steel fibers produced a slight reduction in compressive strength and stiffness at early curing ages; however, comparable mechanical performance was achieved after extended curing. The observed improvements are primarily consistent with the filler effect and improved particle packing associated with the fine tailings fraction, although the underlying microstructural mechanisms were not directly evaluated in this study. Overall, the results provide preliminary evidence that copper tailings can be incorporated into laboratory-cast concrete mixtures with steel fibers, supporting their further evaluation for potential underground support applications. Full article

The growing interest in sustainable materials has stimulated interest in biodegradable biocomposites produced from renewable and industrial by-product resources. In this study, the feasibility of replacing wood particles with nigella, rapeseed, and evening primrose pomace residues in modified thermoplastic starch (MS)-based composites was investigated. Composite boards were manufactured using lignocellulosic filler containing wood substituted by untreated pomace at different substitution levels (30%, 65%, and 100%) and matrix ratios (30% and 40%). Mechanical performance, surface roughness, wettability, and water stability were evaluated. Pomace content was the dominant factor affecting MOR, and contact angle. Increasing wood substitution reduced the MOR. Intermediate levels of nigella substitution reduced surface roughness. Rapeseed and evening primrose residues improved resistance to water-induced disintegration at higher substitution levels, whereas composites containing nigella residues remained highly susceptible to degradation during soaking. The results demonstrate that unmodified oil press residues can serve as alternative lignocellulosic fillers in starch-based biocomposites and provide a promising route for valorization of agro-industrial by-products. Full article

Accurate determination of mixing and compaction temperatures is essential for producing durable asphalt pavements while minimizing energy consumption and binder aging. Conventional temperature selection is based on asphalt binder viscosity, which does not adequately represent the workability of modern asphalt mixtures containing polymer modifiers or alternative mineral fillers. This study proposes a torque-based criterion as a performance-oriented alternative for estimating the required production temperatures of conventional and polymer-modified asphalt mixtures. A high-capacity laboratory workability device was developed to measure the mixing torque of 15 kg asphalt mixtures at temperatures ranging from 120 to 160 °C. The experimental program included surface, binder, and base mixtures incorporating hydrated lime, limestone, and cement fillers, as well as asphalt modified with 4% styrene-butadiene-styrene (SBS) and 5% polyvinyl chloride (PVC). Based on the experimental results, torque criteria were established for conventional hot mix asphalt, and regression models were developed to estimate the production temperatures of polymer-modified mixtures. The proposed torque-based approach predicted mixing temperatures of 163–192 °C and compaction temperatures of 147–176 °C for SBS-modified asphalt, while the corresponding ranges for PVC-modified asphalt were 131–170 °C and 110–149 °C, respectively. The lower PVC compaction prediction of 110 °C represents an extrapolated model value outside the experimentally investigated temperature range and requires experimental verification before practical application. Compared with the conventional viscosity-based method, the torque criterion reduced the required mixing and compaction temperatures by 13–57 °C (6–30%) and 17–65 °C (9–37%), respectively. Validation using a Superpave gyratory compactor demonstrated nearly identical volumetric properties for the two methods, with %Gmm at Ndesign of 95.90% and 95.88%, and air voids of 4.10% and 4.12%, despite approximately 40 °C lower processing temperatures using the torque-based method. These findings indicate that torque-based workability can provide a practical basis for estimating asphalt production temperatures, while its potential for reducing energy demand, limiting binder aging, and supporting more sustainable pavement construction requires further validation. Full article

The growing demand for sustainable food packaging has spurred interest in biodegradable active films. This study aimed to develop novel polylactic acid/tetraethyl citrate (PLA/TEC) composite films reinforced with curcuma, mustard, and ginger powders for extending the shelf life of fresh minced meat. Films incorporating 5, 10, and 15 wt% of each powder were prepared via melt extrusion and compression, and characterized by XRD, FTIR, tensile testing, oxygen barrier measurements, DPPH antioxidant assays, and antibacterial tests against Listeria monocytogenes and Escherichia coli. Optimal 10 wt% formulations were applied to fresh minced pork and evaluated for microbial quality, lipid oxidation, and sensory properties over 8 days at 4 °C. Curcuma powder exhibited the strongest plasticizing effect, increasing elongation at break up to 410%, while ginger acted as a reinforcing filler. The 10 wt% formulations provided the best oxygen barrier (OTR: 55.4–61.8 cc/m²·day). Curcuma showed the highest antioxidant activity (EC₅₀ = 34.4 mg/mL at 15 wt%), followed by ginger and mustard, while antibacterial activity was moderate for all films. In meat packaging tests, all three active films extended shelf life by approximately 2 days compared to PLA/TEC, with curcuma-based films showing the best overall performance in delaying microbial growth and lipid oxidation. The PLA/TEC matrix effectively accommodated high loadings of natural spice powders, yielding flexible, fully bio-based active films. Curcuma-containing films demonstrated the most promising balance of properties, offering a viable sustainable alternative for fresh meat packaging. Full article

Dental resin composites are widely used for direct restorations, yet their longevity remains limited by biofilm accumulation and secondary caries at the tooth–restoration interface. Unlike previous reviews that have primarily organized antibacterial dental materials according to antimicrobial agents or mechanisms, this narrative review evaluates antibacterial resin composites from a polymer-composite design perspective, integrating molecular architecture, network immobilization, filler–matrix interactions, polymerization, and aging. Leachable agents such as chlorhexidine provide early antibacterial effects but are constrained by reservoir depletion, water sorption, and release-related material changes. In contrast, covalently immobilized quaternary ammonium monomers provide sustained surface-associated activity without continuous release, although their performance depends on molecular structure, concentration, degree of conversion, and network properties. Antibacterial nanoparticles and bioactive glass fillers provide composition-dependent ion-mediated, photocatalytic, pH-modulating, and remineralizing effects, while their performance depends strongly on particle characteristics, dispersion, and formulation. Multifunctional systems further combine antibacterial activity with protein repellence, mineral protection, and rechargeable ion release. Overall, the evidence indicates that durable antibacterial performance cannot be considered independently of polymerization, mechanical integrity, aging stability, and biocompatibility. Future development should therefore prioritize clinically relevant multispecies biofilm models, standardized aging protocols, structure–property analysis, and long-term in vivo and clinical validation. Full article

This study investigates the feasibility of utilizing stone dust waste, an industrial by-product generated during ornamental-stone quarrying processing, as a raw material for 3D-printing mortar. This approach reduces waste disposal and promotes a circular economy. Several high-strength cementitious mixtures were screened and optimized by varying raw materials as a function of slump flow evolution over time, which served as indirect assessment of open time and extrudability. Following the identification of the most suitable mixture for 3D printing, one of the raw materials (an ultrafine limestone filler) was subsequently replaced on a 1:1 mass basis with stone waste, selected due to its comparable particle-size distribution, to assess its feasibility as an alternative filler. Fresh-state properties were evaluated based on flowability, with slump values ranging from 16 cm to 13 cm over time, and extrusion tests on a screw pump, used to validate extrusion stability and shape retention. Hardened-state properties were determined at different curing ages. The incorporation of Apricena stone waste resulted in similar fresh-state and extrusion behaviour of mortar, without additional changes to the mix design, and the intended 30 min qualitative extrusion window was met. At 28 days, the mixture incorporating stone dust waste achieved flexural and compressive strength of 12.51 MPa and 79.72 MPa. The incorporation of stone dust waste resulted in an extrudable mixture for 3D printing, with the intended open time and fresh-state behaviour, as well as mechanical properties complying with high-strength applications. However, the full replacement of one of the limestone fillers led to an 8% reduction in 28-day compressive strength. Overall, the findings demonstrate that the recovery of stone dust slurry as viable supplementary cementitious material for 3D-printed concrete is viable. The data support the use of this stone waste as a raw material for 3D printing, and specific mortar development and mix optimization for different applications are recommended, including the quantitative assessment of buildability, printed mechanical properties, durability, and leaching and life-cycle assessment. Full article

In the last few years, the tyre industry has faced new sustainability challenges, mainly regarding the substitution of fossil-based ingredients with bio-based raw materials. In fact, most of the largest tyre companies worldwide have publicly declared the objective of producing tyres with 100% sustainable materials by 2050. The main ingredients in a tyre compound are the polymer matrix and the reinforcing filler, but while natural rubber (NR) already represents a well-established bio-based alternative to synthetic polymers, the replacement of conventional reinforcing fillers remains a significant challenge. In fact, carbon black (CB), a fossil-based raw material produced from petroleum-derived feedstock, is still the main filler used in rubber compounds worldwide. A promising candidate for its replacement could be Microfibrillated cellulose (MFC): a bio-based, biocompatible, renewable, and non-toxic material, also obtained from waste biomass, with a lower density and a higher surface reactivity with respect to CB. However, the polar functional groups on its surface make it extremely incompatible with the non-polar rubber matrices used for tyre formulations. To overcome this limitation, effective compatibility strategies are required to exploit and boost these surface functionalities and promote the formation of a novel filler–polymer network. In this work, a new approach for MFC functionalisation is developed, and the synthesis and characterisation of the modified material are reported. This strategy is further applied to develop innovative MFC-reinforced epoxidised natural rubber (ENR) compounds, whose properties are compared to conventional CB-filled systems. Full article

The demand for materials with flame-retardant and electromagnetic shielding properties has increased research on sustainable and multifunctional composites. Thermoset-based hybrid composites containing Fe₃O₄ and activated carbon obtained from solid waste were investigated for flame retardancy and electromagnetic shielding. Activated carbon produced by pyrolysis of buckwheat hulls (agricultural waste) exhibited a BET surface area of 714.33 m²/g and a conductivity of 69.5 S/m, and was used as a filler to enhance electrical conductivity, while Fe₃O₄ was added to promote electromagnetic absorption. Composites with 1, 3, 5 and 7 wt% activated carbon at a constant 15 wt% Fe₃O₄, together with a complementary series at 5 wt% activated carbon with 10, 15, 30 and 45 wt% magnetite, were characterized by limiting oxygen index and thermal analysis. LOI values clustered between 32.31% (Nov-5-15) and 33.71% (Nov-3-15), a 1.40-percentage-point spread around the 34.31% reference Novolac. The 850 °C char yield peaked at 56.38% (Nov-3-15) and 55.34% (Nov-7-15), with T₅₀% reaching 898 °C and 882 °C, respectively, while DTA replaced the 529 °C Novolac exotherm with endothermic Tmax values of 485–501 °C. Electromagnetic shielding effectiveness over the 8–12 GHz range varied from 2.97 ± 0.3 dB (unfilled Nov-0) to a maximum of 9.19 ± 1.46 dB (Nov-5-45, 5 wt% activated carbon and 45 wt% Fe₃O₄), with an intermediate value of 7.43 dB for Nov-7-15. These hybrids are thus candidate materials for fire-safe phenolic-thermoset applications, where magnetic–dielectric coupling and a percolated char-barrier network govern flame-retardant performance, demonstrating the potential of waste-sourced carbon in sustainable composite production. Full article

Polymer nanocomposites have attracted considerable attention owing to their ability to achieve substantial improvements in mechanical, thermal, electrical, barrier, and multifunctional properties through the incorporation of low concentrations of nanoscale fillers. This review provides a comprehensive analysis of recent advances in polymer nanocomposites, focusing on the relationships between nanofiller characteristics, processing strategies, interfacial interactions, and the resulting material performance. Different classes of nanofillers, including carbon-based, ceramic, metallic, polymeric, and hybrid nanostructures, are systematically compared with respect to their morphology, surface chemistry, of processing routes, including melt blending, solution processing, in situ polymerization, and surface functionalization, on nanoparticle dispersion and polymer–nanofiller interfacial adhesion is critically discussed. The review further evaluates how these factors govern the mechanical, thermal, electrical, dielectric, and barrier properties of polymer nanocomposites and summarizes their applications in aerospace, automotive engineering, electronics, biomedical devices, energy systems, construction, and advanced packaging. Current technological challenges, including nanoparticle aggregation, long-term stability, process scalability, environmental impact, and nanomaterial safety, are also examined. Finally, emerging research directions, including hybrid nanofillers, sustainable polymer systems, digital materials design, and machine-learning-assisted optimization of polymer nanocomposites, are highlighted. This review provides an integrated perspective on the design and processing of high-performance polymer nanocomposites and identifies key opportunities for future research and industrial implementation. Full article