Search Results (466)

Carbon black (CB) nanoparticles (~20 nm) offer high specific surface area and conductivity for self-sensing cementitious composites, but strong interparticle van der Waals forces drive agglomeration in alkaline pore solutions, limiting sensing reliability. This study introduces a nanoscale interfacial engineering strategy in which CB nanoparticles are adsorbed onto polypropylene (PP) fiber surfaces as spatially organized conductive elements, with EDS evidence of enhanced hydrate coverage at the fiber–matrix interface. Three CB dosages (0.5%, 1.0%, and 1.5% by binder mass) with 0.5% PP fiber were investigated. Nanoparticle coating and interfacial micro-structure were characterized by SEM-EDS, while FTIR was used to verify that the fiber backbone remained chemically unmodified; piezoresistive response and durability were assessed via cyclic compression, DIC, and hygrothermal cycling. The 1.0% CB nanocomposite lies within the effective percolation window (~0.9–1.2%), showing high linearity, a stable gauge factor (~100), and distinct FCR acceleration for early-warning sensing. The 1.5% CB composite yields higher sensitivity but scattered responses due to nanoparticle clustering; 0.5% CB remains below the percolation threshold with a discontinuous network. After 60 hygrothermal cycles, the 1.0% nanocomposite retains >93% of its gauge factor with minimal resistance drift. The nano-engineered CB–PP fiber architecture offers a scalable route integrating crack bridging, percolation networking, and durable self-sensing in cementitious nanocomposites for structural health monitoring. Full article

Multifunctional polymer scaffolds with mechanical support, biocompatibility, and antimicrobial activity are key for next-generation biomedical materials. We report the fabrication of electrospun nanocomposite fibers made from polycaprolactone (PCL), starch, and mesoporous aluminum oxide nanoparticles (n-Al₂O₃). Nanoparticles (11 ± 4 nm) were synthesized via a sol-gel method, predominantly comprising γ- and α-Al₂O₃ phases. Four fiber systems were fabricated by side-by-side electrospinning: PCL, PCL/starch, PCL/n-Al₂O₃, and PCL/starch/n-Al₂O₃. SEM analysis confirmed uniform and bead-free fibers in all formulations. Tensile tests showed that the incorporation of starch and nanoparticles improved the mechanical performance compared with neat PCL. In particular, PCL/starch/n-Al₂O₃ fibers exhibited increases of 404% in Young’s modulus and 102% in elongation at break. In PBS, starch and n-Al₂O₃ enhanced hydrophilicity and accelerated weight loss, with PCL/starch/n-Al₂O₃ showing the highest mass loss. Antibacterial tests indicated that only fibers with nanoparticles could inhibit Staphylococcus aureus and Escherichia coli, with PCL/starch/n-Al₂O₃ showing a major effect. Although n-Al₂O₃ increased cytotoxicity toward NIH-3T3, starch mitigated this effect, and the ternary scaffold showed no detectable cytotoxicity. Moreover, PCL/starch/n-Al₂O₃ exhibited non-hemolytic behavior, enhanced fibroblast migration, and wound-healing-related protein expression. Overall, side-by-side electrospun PCL/starch/n-Al₂O₃ scaffold exhibited showed improved mechanical, biological, and antibacterial properties, supporting its potential as a wound-dressing material. Full article

Polybenzoxazines (PBz) represent a versatile class of high-performance thermosetting polymers that have attracted significant attention for advanced composite applications due to their unique combination of properties including high glass transition temperatures, low polymerization shrinkage, excellent thermal stability, and molecular design flexibility. This comprehensive review examines the structure–property relationships governing PBz composite performance, from molecular design principles through network formation, composite reinforcement strategies, and ultimate application performance. The review systematically addresses benzoxazine monomer structure and its influence on polymer network architecture, explores the polymerization mechanism, and critically evaluates composite design strategies incorporating carbon-based nanofillers, fiber reinforcements, and hybrid filler systems. Detailed analysis of structure–property relationships reveals how molecular and composite architecture control thermal stability (glass transition temperatures exceeding 350 °C and char yields up to 92%), mechanical performance, electrical properties (dielectric constants as low as 2.67), and chemical durability. Processing techniques ranging from conventional compression molding to emerging additive manufacturing approaches are discussed in the context of morphological control and property optimization. Applications spanning aerospace structures, high-frequency electronics and protective coatings demonstrate the technological relevance of PBz composites. Critical challenges including network brittleness, high cure temperatures, and recyclability limitations are addressed alongside recent advances in dynamic covalent networks, vitrimer chemistry, and self-healing systems that promise to overcome these barriers. This review provides a comprehensive framework for understanding and engineering polybenzoxazine composites for next-generation advanced applications. Full article

Polylactic acid (PLA) is a biodegradable polymer suitable for selective laser sintering, yet the atomic-level sintering mechanisms of plant-fiber-reinforced PLA remain largely unclear. Here, all-atom molecular dynamics simulations are used to investigate the sintering behavior and interfacial interactions of cotton stalk cellulose/PLA nanocomposites with cellulose contents of 0–20 wt%. The nanoparticle coalescence proceeds through three sequential stages: initial van der Waals-driven contact, thermally activated neck formation, and isothermal interfacial densification. Cellulose content exerts a non-monotonic effect on interfacial bonding. At 15 wt% cellulose, an optimal, continuous hydrogen-bond network forms between cellulose hydroxyls and PLA carbonyls, maximizing interfacial adhesion while simultaneously suppressing unfavorable dipole stacking among PLA chains. At this critical loading, cellulose acts as a rigid scaffold that directs PLA chain extension and directional migration across the sintering neck, as evidenced by atomic displacement and radius-of-gyration analyses. In contrast, excess cellulose (20 wt%) induces self-aggregation, which disrupts interfacial continuity and hinders long-range chain diffusion. These results identify 15 wt% as the optimal cellulose content for achieving enhanced interfacial bonding and chain mobility, providing atomistic criteria for the formulation design of cellulose/PLA composite powders for selective laser sintering processing. Full article

Thermally sprayed metallic coatings on carbon fiber-reinforced polymer (CFRP) substrates often contain pores and microstructural defects that can reduce adhesion, durability, and protective performance. In this study, a hybrid graphene nanoplatelet (GNP)-fullerene C60 reinforced epoxy coating was applied to HVOF-metallized CFRP, while a carbon nanotube (CNT)-based surface treatment was used to modify surface wettability. Micro-CT and SEM analyses indicated morphological changes consistent with partial coverage of accessible surface-connected defects and modification of the metallized layer surface. Pull-off adhesion strength increased from 320 psi to 650 psi, accompanied by a shift from adhesive to cohesive failure. The optimal nanofiller formulation improved tensile strength from approximately 25 MPa to 56 MPa (124%) and Young’s modulus by approximately 47% compared with neat epoxy. Abrasion testing showed more than 50% reduction in mass loss, and electrochemical impedance spectroscopy indicated improved barrier performance after 200 h of salt spray exposure. CNT surface modification transformed the coating from hydrophilic to superhydrophobic behavior, achieving water contact angles above 155°, delaying ice formation, and reducing ice accumulation. These results indicate that combining hybrid nanocomposite coatings with CNT functionalization can improve mechanical, protective, and surface-functional performance of HVOF-metallized CFRP systems under the laboratory conditions investigated. Full article

Electrospun nanocomposite membranes have attracted considerable interests for flexible energy-storage devices; however, the influence of graphene derivative surface chemistry on the electrochemical behavior of cellulose acetate-based nanocomposites remains insufficiently understood. In this work, cellulose acetate (CA) nanocomposite membranes containing graphene oxide (GO), reduced graphene oxide (rGO), and octadecylamine-functionalized reduced graphene oxide (rGO-ODA) at concentrations of 0.1 and 0.2 wt% were fabricated by electrospinning and evaluated as electrode materials for supercapacitor applications. The interfacial interactions and morphology of the membranes were investigated by Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM), respectively, while electrochemical performance was assessed by cyclic voltammetry in three-electrode and symmetric two-electrode configurations. FTIR analysis confirmed effective interactions between the graphene derivatives and the CA matrix, whereas SEM observations revealed that nanofiller chemistry influenced fiber morphology and structural homogeneity. Among the evaluated systems, GO-containing membranes exhibited the best electrochemical performance, reaching a specific capacitance of 5.982 F/g in the three-electrode configuration. Analysis of the charge-storage mechanism using the power-law relationship revealed distinct electrochemical behavior associated with the surface chemistry of each graphene derivative. The results demonstrate that graphene-derivative chemistry governs the structure-property relationships, electrochemical response, and charge-storage behavior of electrospun CA nanocomposites, providing fundamental insights for the design of lightweight and flexible electrodes for energy-storage applications. Full article

The growing demand for environmentally sustainable materials has accelerated the development of bio-based coatings as alternatives to conventional petroleum-derived surface treatments. Among renewable biopolymers, lignin has emerged as a particularly attractive candidate owing to its abundance, renewable origin, aromatic structure, antioxidant activity, ultraviolet shielding capability, and diverse functional groups suitable for chemical modification. As a major by-product of the pulp, paper, and biorefinery industries, lignin represents an underutilized renewable resource with significant potential for value-added coating applications. This review provides an overview of recent advances in lignin-based coatings for sustainable and biodegradable materials. The chemical structure, physicochemical properties, industrial sources, extraction technologies, purification methods, and functionalization strategies of lignin are discussed. Particular attention is given to nanostructured lignin systems, including lignin nanoparticles (LNPs) and chemically modified derivatives, which have demonstrated improved compatibility and performance in coating formulations. Fabrication technologies such as solution casting, dip coating, spray coating, layer-by-layer (LbL) assembly, extrusion processing, and nanocomposite approaches are examined. Mechanical, barrier, thermal, UV-shielding, antioxidant, antimicrobial, hydrophobic, and environmental performance are comparatively assessed. Lignin nanoparticles and chemically modified lignins generally show improved functionality, while waterborne coatings for paper and fiber-based packaging appear closest to practical application. However, lignin heterogeneity, durability, scalability, and limited regulatory evaluation and end-of-life assessment remain major barriers to commercialization. Full article

The growing demand for sustainable food packaging materials has accelerated the development of biodegradable alternatives to conventional petroleum-based plastic. This study investigates the reinforcement of electroblown gelatin/polyvinyl alcohol (G-PVA) nanofibrous mats with kombucha-derived bacterial cellulose nanowhiskers (BCNWs) to enhance their mechanical, thermal, and surface properties while promoting the valorization of symbiotic culture of bacteria and yeast (SCOBY) waste. BCNWs were incorporated into the G-PVA matrix at different loadings, and the resulting nanocomposites were characterized using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), tensile testing, and water contact angle measurements. The addition of BCNW significantly improved the tensile strength of the nanofibrous mats, with a maximum increase about 120% compared with neat G-PVA nanofibers. SEM images revealed uniform, bead-free fiber structures at appropriate BCNW concentrations, while FTIR and XRD analyses confirmed effective interactions between the nanowhiskers and the polymer matrix. TGA results indicated enhanced thermal stability at moderate BCNW loadings, whereas excessive BCNW content promoted agglomeration and reduced thermal resistance. Furthermore, the incorporation of BCNWs increased the water contact angle to 144.11 ± 1.45°, demonstrating improved surface hydrophobicity. Overall, kombucha-derived BCNWs effectively reinforced electroblown G-PVA nanofibers, producing biodegradable nanocomposite mats with improved performance and strong potential for sustainable food packaging applications. Full article

Additive manufacturing (AM) has evolved from a rapid prototyping technique into a versatile platform for fabricating advanced functional materials and complex engineering components. While polymers remain the dominant material class due to their processability and tunable properties, recent developments have expanded AM to include high-performance composites, nanocomposites, and metallic materials. This review provides an overview of functional materials for additive manufacturing, emphasizing the relationships between material design, processing conditions, microstructure evolution, and resulting properties. Key functional polymer systems are discussed, including conductive, stimuli-responsive, elastomeric, high-performance, bio-based, and nanocomposite materials reinforced with nanoparticles, carbon nanomaterials, MXenes, and fibers. This review also examines processing–structure–property relationships common to polymer- and metal-based AM, highlighting the roles of anisotropy, defect formation, residual stresses, and post-processing in determining component performance. Finally, current challenges and emerging trends—including multi-material and 4D printing, machine learning-assisted optimization, and digital materials design—are discussed. Overall, the review highlights how advances in materials science and intelligent manufacturing are expanding the capabilities of additive manufacturing for multifunctional engineering and biomedical applications. Full article

This work presents a sustainable strategy for the fabrication of multifunctional silver nanoparticles (Ag-NPs) and Ag/jute nanocomposites using Erythroxylum coca tea waste extract as a bioreducing and stabilizing agent, combined with picosecond pulsed laser irradiation. UV–Vis spectroscopy and transmission electron microscopy revealed the formation of Ag-NPs with diverse morphologies and broad size distributions, which became significantly more uniform after laser post-treatment without the need for additional chemical reagents. Following laser irradiation, the initially broad Ag surface plasmon resonance (SPR) peak transformed into a symmetric Gaussian-shaped band, centered at 407 ± 3 nm for all the Ag-NPs systems. The catalytic performance of unsupported Ag-NPs and Ag-NPs supported on jute fibers was comparatively evaluated by degrading Congo red (CR) dye, revealing that the supported nanocomposites exhibited enhanced catalytic stability, higher pollutant removal efficiency, and improved catalyst recovery. Furthermore, multicomponent catalytic reduction experiments involving CR and 4-nitrophenol (4-NP) in the presence of NaBH₄ revealed simultaneous degradation and reduction pathways mediated by the Ag/jute nanocomposites, as evidenced by the emergence of new absorption bands during the reaction. In parallel, the synthesized Ag-NPs demonstrated pronounced antimicrobial activity against Escherichia coli, generating well-defined inhibition zones. Beyond conventional approaches centered on nanoparticle synthesis and morphology optimization, this study establishes a platform that combines agricultural waste valorization, laser-assisted nanoparticle engineering, and natural-fiber-supported nanocomposite fabrication, enabling efficient remediation of both single- and multicomponent pollutant systems while promoting catalyst reusability and environmental sustainability. These findings demonstrate the Ag/jute nanocomposites as sustainable and scalable catalytic materials for wastewater remediation and antimicrobial applications. Full article

Hybrid conductive materials have attracted increasing attention due to their combined electrical conductivity, mechanical flexibility, and sustainability. In this work, new hybrid materials based on polyaniline (PANI)-wrapped multi-walled carbon nanotubes (MWCNTs) and microfibrous cellulosic substrates were developed and assessed for photocatalytic degradation of a model dye pollutant. First, in situ oxidative polymerization of aniline in formic acid (FA) was conducted in the presence of MWCNTs to afford stable dispersions of carboxylated polyaniline-wrapped carbon nanotubes (c-PANI/MWCNTs). Next, the dispersions were used for affordable impregnation of microfibrous cellulosic filter paper. The influence of the initiator type—potassium peroxodisulfate (KPS) and hydrogen peroxide—on polymer–nanotube interactions, stabilization and surface deposition was emphasized. The structural, surface, morphological and thermal properties of the obtained dispersions and cellulose nanocomposites were systematically investigated using Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy and thermal gravimetric analysis. The results revealed strong interfacial interactions between c-PANI and the pristine MWCNTs, resulting in improved dispersion stability and effective and even surface deposition of the conductive c-PANI/MWCNT hybrids into the cellulose fiber mesh. The photocatalytic degradation of 5 ppm methylene blue (MB) dye in the presence of the developed nanocomposite materials under UV-A illumination was studied. The results showed that the c-PANI@MWCNT-impregnated cellulose substrates exhibited enhanced photocatalytic ability (up to 83% degree of degradation of MB dye) in comparison with the pure c-PANI. Full article

In response to the harsh operating conditions of high-speed, high-temperature bearings in new energy vehicle drive motors, this study focuses on enhancing the performance of polyurea-based gel greases through the use of nano-additives. Using polyurea-based gel grease as the matrix, nano-composite gel greases with different CeO₂ loadings were prepared, and their tribological properties and rheological behavior were characterized using four-ball friction tests, rheological testing, and SEM analysis. The results indicate that adding 0.5 wt% CeO₂ increased the grease’s yield stress by approximately 75.4% and significantly raised its apparent viscosity. This rheological enhancement effect may be attributed to the physical adsorption of ultrafine particles onto the polyurea fiber network and potential interfacial interactions between the particles and the fiber surfaces. Compared to the original grease, the average coefficient of friction decreased by 10.4%, and the average wear scar diameter decreased by 12.7%. Meanwhile, the shear stress increased by 110.41 Pa, and the viscosity increased by 1102 Pa·s. This study provides experimental evidence and technical references for the development of high-performance gel lubricants suitable for motor bearings operating under high-temperature conditions. Full article

Background/Objectives: Wound infections represent a major clinical challenge due to their polymicrobial nature, biofilm formation, and increasing antimicrobial resistance, which compromise conventional treatments. This study aimed to develop and evaluate ligand-stabilized silver nanoparticles (AgNPs) with improved antimicrobial activity and cytocompatibility, and to investigate their incorporation into electrospun nanofibers for wound management. Methods: Four AgNP formulations stabilized with citrate, cysteine, ketorolac, and diclofenac were synthesized via chemical reduction. Physicochemical characterization included surface plasmon resonance and zeta potential measurements. Antimicrobial activity was assessed through minimum inhibitory concentration (MIC) and bactericidal assays against Gram-positive, Gram-negative, and fungal strains. Toxicity was evaluated using the HET-CAM assay, while cytocompatibility was determined in fibroblasts, MG-63 cells, and mesenchymal stem cells. Diclofenac-stabilized AgNPs were incorporated into electrospun PCL/PEO nanofibers to generate a functional nanocomposite system. Results: All AgNPs exhibited a characteristic SPR at ~400 nm and high colloidal stability. Diclofenac-stabilized AgNPs (dc-AgNPs) showed the highest antimicrobial activity, with MIC values of 18.8 mg/L against Staphylococcus aureus and Pseudomonas aeruginosa, and 4.7 mg/L against Candida albicans, along with strong bactericidal effects. HET-CAM assays indicated negligible irritation at concentrations up to 75 mg/L. Cytocompatibility results revealed a dose-dependent response, with fibroblasts being more sensitive. Electrospun nanofibers loaded with dc-AgNPs achieved a 2.6 log reduction against Streptococcus mutans and moderate reductions (0.4–0.7 log) against other pathogens. Conclusions: Ligand engineering critically influences the antimicrobial efficacy and biocompatibility of AgNPs. The incorporation of dc-AgNPs into electrospun nanofibers represents a promising approach for treating biofilm-associated wound infections. Full article

The increasing global frequency of harmful cyanobacterial blooms (CyanoHABs), driven by nutrient enrichment and climate change, poses a severe threat to aquatic ecosystems and public health. This study evaluates the effectiveness of novel clay–polymer nanocomposites (CPCs) that combine the charge-neutralizing capabilities of polydiallyldimethylammonium chloride (polyDADMAC) with the high clay mineral density (kaolinite and sepiolite) for rapid removal of toxic cyanobacteria from water. Laboratory experiments were performed using Microcystis aeruginosa, Aphanizomenon ovalisporum, and Chlorella sp., with treatment doses determined by particle charge detector (PCD) measurements to identify the “nominal dose” required for full charge neutralization. Results show that clay–polymer nanocomposites achieve over 95% removal of turbidity and chlorophyll in M. aeruginosa at doses significantly lower (15–20%) than the calculated nominal dose, likely due to specific physical bridging interactions with the cyanobacteria’s external exopolysaccharide fibers. In contrast, A. ovalisporum and Chlorella sp. required doses closer to full charge neutralization for optimal removal. Among the materials tested, kaolinite-based nanocomposites (DKG24) showed slightly superior, more stable performance than sepiolite-based nanocomposites. Notably, application at or above the nominal dose was associated with increased soluble microcystin levels, suggesting that excessive polymer concentrations may compromise cell integrity and lead to toxin leakage. These findings suggest that engineered nanocomposites offer highly efficient, scalable technology for CyanoHAB management, provided that operational doses are carefully optimized to maximize biomass removal while minimizing toxin release. Full article

This study investigates the mechanical performance, high-temperature resistance, and microstructural characteristics of ground granulated blast furnace slag (GGBFS)-based geopolymer composites reinforced with boron nitride (BN)-modified hemp nanofibers. BN-modified hemp nanofibers (PVA-mBN/Hemp) were produced via electrospinning and incorporated into geopolymer mixtures at varying ratios ranging from 0 to 4 wt%. The effects of nanofiber content on composite properties were evaluated through mechanical testing, ultrasonic pulse velocity (UPV) measurements, and exposure to elevated temperatures (300–1200 °C), supported by SEM-EDS, FTIR, and XRD analyses. The results indicate that low nanofiber additions (0.5–1 wt%) improve flexural strength by up to 15%, although compressive strength is slightly reduced due to increased porosity. UPV measurements confirm the changes in internal structure. At elevated temperatures, nanofiber-reinforced samples exhibit enhanced residual strength compared to the control specimens, particularly at moderate temperatures, whereas significant degradation occurs above 900 °C. Microstructural analyses reveal improved fiber-matrix interaction, reduced crack propagation, and enhanced thermal stability attributed to BN modification. Overall, the incorporation of 0.5–1 wt% BN-modified hemp nanofibers provides an effective balance between mechanical performance and high-temperature resistance, highlighting their potential for use in sustainable and fire-resistant construction materials. This study contributes to the United Nations Sustainable Development Goals (SDGs), particularly SDG 9 (Industry, Innovation, and Infrastructure), SDG 11 (Sustainable Cities and Communities), and SDG 12 (Responsible Consumption and Production). Full article