Search Results (288)

The present study demonstrated the fabrication of a sustainable, high-performance composite by upcycling waste denim fabric within a cyanoacrylate matrix reinforced with B₄C micro-particles (4, 7, and 10 wt%). XRD and SEM analyses confirmed the successful integration of the ceramic filler and effective fiber encapsulation, with particle agglomeration identified at 10 wt% loading. The 7 wt% B₄C composition exhibited the highest static mechanical performance, with a tensile strength of ~20.3 ± 1.3 MPa and Young’s modulus of 1.17 GPa—improvements of ~22.8% and ~41% over the unreinforced denim–cyanoacrylate composite—while at 10 wt% B₄C the ultimate tensile strength declined below the unreinforced baseline and the Young’s modulus reverted to a comparable value, likely reflecting agglomeration-induced stress concentration as a major contributing factor. Under dynamic impact loading, the peak contact force increased monotonically from 0.34 kN to 1.31 kN with increasing B₄C content yet remained well below the thresholds specified by international impact protection standard thresholds across all compositions. This divergence between static and dynamic responses indicates that the increase in contact force with B₄C content reflects progressive stiffening and more direct load transfer rather than improved energy attenuation, whereas tensile performance depends critically on dispersion quality and fiber–matrix adhesion. Surface wettability analysis showed a marked increase in hydrophobicity, with the water contact angle rising from 105 ± 4° to 133 ± 4° (for the DSGB-7 wt% composite), consistent with a Cassie–Baxter wetting regime. These preliminary results suggest that B₄C-reinforced waste denim–cyanoacrylate composites merit further investigation as candidate materials platform for protective textile applications, pending validation through larger-scale, standardized testing. Full article

Okra (Abelmoschus esculentus) stems represent an abundant lignocellulosic resource with considerable potential for sustainable textile and bio-composite applications. This study investigated the effects of biological, alkaline (1–7.5 wt.% NaOH), and combined extraction methods on the physicochemical, structural, and mechanical properties of okra fibers. FTIR and XRD analyses confirmed the progressive removal of hemicellulose and lignin, resulting in increased cellulose crystallinity after alkaline treatment. Optical microscopy revealed enhanced fiber individualization and cleaner surface morphology. Increasing the NaOH concentration improved fiber density, reduced hygroscopicity, and enhanced mechanical performance. The highest cellulose content (76.52%), tensile strength (148.57 MPa), and Young’s modulus (6.62 GPa) were achieved with 7.5 wt.% NaOH treatment. However, excessive treatment severity induced partial cellulose degradation. Overall, alkali-treated okra fibers exhibited improved structural organization, reduced moisture sensitivity, and enhanced mechanical properties, highlighting their potential as lightweight and sustainable reinforcements for technical textile and bio-composite applications. Full article

Carbon nanotube (CNT)- and graphene flake (GF)-modified polyester (PET) nonwoven composites were prepared using a one-sided impregnation process with waterborne polyurethane (PU) as the binder. The objective of this work was to clarify how the geometry and loading of one-dimensional CNTs and two-dimensional GFs regulate conductive network formation, anisotropic mechanical behavior, and thermal response in PU/PET nonwoven composites. The novelty of the study lies in the direct comparison of CNT and GF fillers in the same nonwoven/PU matrix and in correlating filler morphology with mechanical reinforcement, electrical conductivity, and textile-related thermal management performance. The sample codes C5 and C6 represent CNT contents of 5 and 6 wt.%, respectively, while G4 and G6 represent GF contents of 4 and 6 wt.%, respectively. Scanning electron microscopy (SEM) showed that GF tended to form sheet-like coatings on fiber surfaces and to fill inter-fiber pores, whereas CNTs showed more local aggregation because of their high surface energy. The composites exhibited anisotropic tensile behavior, with higher tensile strength in the longitudinal direction than in the transverse direction. In the longitudinal tensile test, G4 reached a tensile strength of 13.01 MPa, while C5 reached 11.35 MPa. With increasing carbon material content, both the electrical and thermal conductivities of the composites increased. The electrical conductivity reached 0.02100 S/cm for C6 and 0.05893 S/cm for G6. The thermal conductivity of the CNT/PU/PET composites increased from 0.1163 to 0.1923 W/(m·K), whereas that of the GF/PU/PET composites increased from 0.1793 to 0.2537 W/(m·K). Infrared thermal imaging further indicated that carbon material addition produced faster heating and slower heat dissipation than the unmodified PU/PET sample. These results provide a useful reference for developing multifunctional nonwoven composites for smart textiles, special protective clothing, wearable thermal management layers, and flexible electronic textile substrates. Full article

In response to the increasing needs for environmentally friendly products, lignocellulosic natural fibers have been of interest as potential replacements for synthetic reinforcement materials in textiles, composites, and related applications. Among these resources, bast fibers derived from plant stems (flax, hemp, nettle, jute, hop), which contain a high cellulose content, have good mechanical properties, low density, and are renewable, are highly promising. Steam explosion has emerged as a green fiber extraction, defibrillation, and surface modification pretreatment technology. Despite the growing number of studies on steam-exploded natural fibers, a comprehensive understanding of the relationships between processing conditions, fiber modifications, mechanisms, and end-use performance remains limited. This review investigates the structural, chemical, and morphological influences of steam explosion on bast fibers. Specifically, it focuses on the mechanism of steam explosion including the solubilization of hemicellulose, partial lignin redistribution or removal, fiber individualization, and cellulose enrichment. The literature indicates that steam explosion can improve fiber separation, fineness, surface morphology, and interfacial adhesion of the composite materials and reduce the use of hazardous chemicals compared with conventional extraction methods. Nonetheless, conflicting results have also been documented, where the same steam explosion conditions can yield distinct fiber characteristics according to biomass type, composition of biomass, moisture concentration, and the amount of processing involved. Excessive treatment severity may lead to fiber shortening, cellulose degradation, and deterioration of fiber quality, particularly for textile applications requiring long fibers. This review highlights current knowledge gaps regarding the optimization of processing conditions, the understanding of steam explosion mechanisms, and the scale-up of the technology for industrial applications. Full article

Alkali-activated materials (AAMs) based on industrial by-products, such as ground granulated blast furnace slag (GGBFS), are increasingly considered sustainable alternatives to Ordinary Portland Cement (OPC) due to their lower environmental impact and favorable mechanical performance. Among the key parameters controlling the behavior of alkali-activated systems, the chemical composition and modulus of the alkaline activator play critical roles in determining the reaction kinetics and material properties. This study investigates the influence of potassium silicate modulus (Ms), defined as the molar ratio of silica to alkali oxide (SiO₂/K₂O), on the reactivity, setting time, flowability, and mechanical properties of alkali-activated slag pastes. Potassium silicate solutions with moduli ranging from 1.0 to 2.5 were used as activators for GGBFS. Paste specimens with different activator moduli were prepared and cured at 20 °C and 75% relative humidity for mechanical testing. The results show that the activator modulus significantly affects the fresh properties, particularly at higher modulus values. Increasing the modulus delays reactivity and prolongs the setting time, whereas the flowability of the fresh paste decreases. Nevertheless, the flowability of the mixtures remained sufficient to allow proper penetration between open textile meshes, which is essential for textile-reinforced cement/concrete (TRC) applications. No clear systematic trends were observed in the mechanical properties, including the elastic modulus, flexural strength, and compressive strength. Full article

Driven by the growing demand for functional textiles featuring excellent waterproofness, moisture permeability and mechanical robustness in outdoor sportswear, medical protection and technical apparel, traditional pongee—despite its desirable softness, high wrinkle resistance and good stability as an ideal substrate fabric—is severely restricted in further application by its intrinsically poor hydrostatic pressure resistance in extremely wet environments. Accordingly, we developed a modified waterborne polyurethane (WPU) coating for pongee substrates to fabricate functional textiles that maintain high hydrostatic pressure resistance while possessing good mechanical properties and increased UV absorption. In this study, by using the sol–gel method, an amorphous silicon dioxide (SiO₂) coating layer was constructed on the surface of titanium dioxide (TiO₂) particles, forming silica-modified titania particles (SiO₂/TiO₂). These SiO₂-modified particles were subsequently physically blended with an anionic waterborne polyurethane system that had been previously modified with a polyester-type modifier A to enhance its hydrostatic pressure resistance. The resulting composite coating was designed to combine the high hydrostatic pressure resistance inherited from the modified WPU matrix, the mechanical reinforcement and increased UV absorption contributed by SiO₂/TiO₂, and satisfactory water repellency on fabric substrates. The results indicate that the incorporation of an appropriate amount of modifier A into the prepolymer system significantly enhances hydrostatic pressure resistance while maintaining high elongation at break. At a SiO₂/TiO₂ loading of 0.2 wt%, the composite film exhibits optimal comprehensive performance, characterized by superior mechanical properties, low water absorption, and static water contact angles exceeding 100° for coated fabrics. SiO₂/TiO₂ composite WPU coatings substantially improve hydrostatic pressure resistance across various fabrics, with 380T polyester taffeta demonstrating the best performance. This resistance remains remarkably stable after standard washing, indicating excellent wash fastness and practical applicability. Full article

Buildings account for a significant share of global energy consumption and carbon emissions, creating an urgent need for advanced energy retrofit technologies. This review critically examines the role of plasma-modified textile polymer materials in improving the energy efficiency and durability of building retrofit systems. Various textile polymers, including polyester (polyethylene terephthalate, PET), polypropylene (PP), polytetrafluoroethylene (PTFE), polyamide (PA), and fiber-reinforced composites, are evaluated in relation to plasma surface engineering approaches, including atmospheric plasma, dielectric barrier discharge (DBD), and plasma jet treatment. Reported studies demonstrate that plasma treatment significantly alters surface morphology and chemistry, resulting in increased surface roughness, enhanced wettability, improved coating adhesion, and superior hydrophobic behavior. Water contact angles increased from approximately 70° to 145° depending on polymer type and plasma conditions, while reflective coating performance improved with solar reflectance enhancements of approximately 10–15%. Plasma-treated reflective roofing and shading textiles also showed reductions in building cooling energy demand of approximately 18–25% and roof temperature decreases of 10–15 °C. Furthermore, plasma-induced surface activation improved durability, ultraviolet (UV) resistance, and weather stability of textile membranes used in facade and roofing applications. The review also discusses industrial challenges related to scalability, plasma aging effects, energy consumption, and long-term performance. Plasma-modified systems demonstrate strong potential for multifunctional, lightweight, and sustainable building envelope technologies for future energy-efficient construction. Full article

This study experimentally investigates the structural behavior of hexagonal- and square-shaped composite specimens subjected to vertical compression, vertical tension, and diagonal tension loading. The specimens were fabricated using four- and six-layer alkali-resistant (AR) glass textile reinforcements embedded in a modified cementitious mortar via pull, pour, and roll manufacturing techniques. The mechanical performance of polyvinyl alcohol (PVA) fiber-reinforced composite connectors and steel clamp-type elements was also evaluated at the joints of hexagonal specimens under vertical tension and lateral shear loading. The results show that increasing the number of textile layers significantly enhances structural performance. A 50% increase in textile layers improved load-carrying capacity by up to 56% in compression, 104% in tension, and 216% in diagonal tension. Corresponding increases of approximately 20–42% in ductility and up to 266% in energy dissipation capacity were observed. No failure occurred in the connecting elements, confirming their adequate stiffness, strength, and ductility. In addition, validated three-dimensional finite element models were developed to simulate the response of the hexagonal specimens. Overall, the proposed system demonstrates strong potential for applications such as infill walls, cladding, and sandwich panels due to its favorable strength, ductility, and energy absorption capacity. Full article

After establishing a lunar settlement, developing resilient infrastructure becomes essential. Transporting prefabricated materials from Earth is costly and logistically challenging, making lunar regolith a promising in situ alternative. Its natural properties support durable, protective construction suited to harsh lunar conditions. This study examines fibre-reinforced composites using LHS-1 and EAC-1 regolith simulants, combining fibre tensile strength with a regolith matrix to improve load-bearing performance. Inspired by textile-reinforced concrete on Earth, this approach enhances tensile capacity and durability compared to unreinforced regolith. Modular components—blocks, panels, structural elements—enable scalable, efficient assembly, supporting adaptable, long-term lunar infrastructure. Full article

Carbon fiber textile-reinforced engineered cementitious composite (CTR-ECC) is widely utilized in structural strengthening applications due to its advantages of low weight and high strength. A comprehensive understanding of its mechanical behavior under off-axis tension is crucial for addressing the prevalent off-axis stress states in engineering practice. This paper presents an experimental investigation on the off-axis tensile properties of CTR-ECC. Specimens were fabricated with four off-axis angles: 0°, 15°, 30°, and 45°. The study revealed three main findings: (1) Under axial (0°) loading, failure is characterized by yarn fracture and interface slip, whereas off-axis tension induces a stable progressive delamination failure in textile-reinforced ECC systems. (2) While CTR-ECC exhibits higher tensile strength than plain ECC at all angles, its strength decreases significantly as the off-axis angle increases (e.g., a 27.1% reduction at 15°). Off-axis layouts, however, substantially improve energy absorption, with strain energy density increasing by up to 368.4% at 30°. (3) A phenomenological constitutive model was developed, which can adequately capture the stress–strain response of CTR-ECC under various off-axis angles, with coefficients of determination (R²) exceeding 0.9 in all cases. These results provide important insights into the failure mechanisms and performance design of CTR-ECC under off-axis tension conditions. Full article

Barely Visible Impact Damage (BVID) in heterogeneous polymer-matrix composites remains difficult to detect because subtle damage signatures are often masked by complex architectures, hybrid textures, and overlapping failure morphologies. This study therefore presents an experimentally grounded, physics-aware, and statistically validated vision-based inspection framework rather than a purely detector-centered benchmarking exercise. Real post-impact images were obtained from controlled low-velocity impact experiments on 20 composite architectures and 60 physical specimens, yielding approximately 2000 images across laminated, hybrid, textile-reinforced, and sandwich structures. The dataset was organized using a specimen-disjoint splitting protocol to prevent leakage across training, validation, and test subsets. To improve robustness while preserving physical realism, a physically grounded Albumentations strategy was developed using only physically admissible transformations and explicit exclusion of non-physical operations that could distort damage morphology or surface continuity. Model development was further complemented by a hybrid hardware workflow in which cloud-based GPU training was combined with deployment-oriented inference profiling on resource-constrained edge-like hardware, thereby linking detection accuracy to practical industrial feasibility. In addition, model performance was evaluated under a standardized training budget and validated through repeated runs, Friedman significance testing, and Holm-corrected Wilcoxon signed-rank pairwise comparisons to ensure error-controlled interpretation of inter-model differences. Across the evaluated compact YOLO families, YOLO26s delivered the strongest overall performance, reaching 0.841 mAP@0.5, 0.586 ± 0.004 mAP@0.5:0.95, and an F1-score of 0.809, while YOLO11s achieved the highest precision and YOLO26n remained competitive in recall with nano-level compactness. Overall, the results show that experimentally generated heterogeneous composite data, morphology-preserving augmentation strategy development, leakage-aware dataset design, deployment-oriented computational profiling, and statistically grounded validation together provide a more robust and application-relevant basis for automated BVID detection in polymer-matrix composite structures. Full article

Fabric-reinforced cementitious matrix (FRCM) composites are strengthening systems composed of a technical textile embedded in a cementitious or lime-based matrix and are increasingly used for strengthening existing masonry and concrete structures due to their compatibility with traditional substrates. The mechanical behavior of FRCM composites is controlled by the combined contribution of the textile reinforcement, the matrix, and the interface developed between them, with the textile–matrix interface playing a critical role in stress transfer, crack development, and post-cracking response. Since this interface is primarily defined by the coating applied to the textile, coating configuration represents a key parameter influencing both the mechanical and durability performance of the composite. In this study, carbon textile–reinforced FRCM systems incorporating a lime-based matrix and different coating strategies, including single-layer SBR coatings and multilayer SBR–epoxy coatings, were experimentally investigated. Tensile tests were conducted on unconditioned specimens as well as after exposure to water and alkaline environments to assess the evolution of tensile behavior and damage mechanisms under durability-related conditioning. The results indicated that the influence of coating configuration is slightly detectable in the pre-cracking elastic stage but becomes significant in the post-cracking stages, where load transfer and damage evolution are predominantly governed by the textile–matrix interface. Scanning electron microscopy (SEM) observations supported the mechanical findings by revealing distinct differences in coating, interfacial continuity, and fiber–matrix bonding, particularly after environmental exposure. Overall, the multilayer coating configuration, consisting of the factory SBR-coated carbon textile further modified with epoxy, resulted in higher maximum tensile strength (reaching up to 1958 MPa compared with 1531–1780 MPa for the single SBR-coated configuration), greater strain capacity (ε_max up to 0.01244 mm/mm compared with 0.00925–0.01066 mm/mm), and higher energy absorption under prolonged water and alkaline conditioning up to 3000 h. In quantitative terms, the multilayer SBR–epoxy coating improved the maximum tensile stress by approximately 10–15% and the total energy absorption capacity by 25–35%, depending on the conditioning regime. These findings demonstrate the effectiveness of multilayer coating architecture in improving long-term tensile retention, interfacial stress transfer, and post-cracking deformation capacity of lime-based carbon FRCM systems. Full article

The recycling of technical textile waste represents a major challenge due to the complex and multilayered structure of these materials. Firefighter protective clothing, mainly composed of high-performance aramid fibers combined with polymeric membranes and auxiliary textile components, is commonly landfilled or incinerated at the end of its service life, resulting in a significant environmental impact. This work utilized recycled aramid-rich textile waste obtained from end-of-life firefighter protective clothing as reinforcement for polyamide 6 to develop high-performance thermoplastic composites within a circular economy framework. Composites containing 15, 30, 45, and 60 wt.% of recycled textile waste were manufactured by melt compounding followed by injection molding. In addition, a selected formulation containing 30 wt.% reinforcement was compatibilized using an amino-functional silane to improve interfacial adhesion. The materials were systematically characterized in terms of tensile properties, thermal behavior, thermomechanical performance, water uptake, flammability, colorimetric properties, and fracture morphology by field emission scanning electron microscopy. The results revealed a pronounced increase in stiffness and thermomechanical stability, with tensile strength increasing from approximately 65 MPa for neat PA6 up to 78 MPa at 30 wt.% reinforcement, and elastic modulus exceeding 5000 MPa at high reinforcement contents. An optimal balance between mechanical performance and ductility was achieved at 30 wt.% reinforcement, while higher contents enabled a substantial extension of the service temperature range, with HDT values increasing from 55 °C for neat PA6 up to 173 °C for highly reinforced systems. FESEM analysis confirmed improved interfacial adhesion in silane-compatibilized systems, explaining the enhanced mechanical and thermomechanical behavior. Furthermore, the incorporation of recycled aramid-rich textile waste led to a significant improvement in flame retardancy, enabling UL-94 V-0 classification at 30 wt.% reinforcement and above, without the use of additional flame-retardant additives, enabling UL-94 V-0 classification without additional flame-retardant additives. Overall, this study demonstrates the technical feasibility and high added-value potential of valorizing firefighter protective clothing waste into advanced PA6-based composites with enhanced mechanical, thermal, and fire-resistant properties, providing a sustainable route for the valorization of high-performance textile waste. Full article

This study investigates hot-pressed composite plates manufactured from pellets obtained by mechanical recycling of post-consumer textile waste and reinforced with ground glass-fiber-reinforced polymer (GFRP) originating from wind turbine blades. Composite plates with dimensions of 200 × 330 × 8 mm were produced by hot pressing at 240 °C under 2 MPa with a heating and pressing time of 40 min. The recycled textile-derived polymer blend served as the matrix, while ground GFRP was introduced at 0, 10, 20, and 30 wt.%. Mechanical performance was evaluated using flexural and Charpy impact tests. The composites exhibited flexural strengths in the range of 9–13 MPa and impact strengths of 7.3–8.9 kJ m⁻². The results did not reveal a monotonic increase in flexural strength with increasing reinforcement content. The highest average flexural strength was observed for the unreinforced matrix, while the addition of ground GFRP resulted in comparable or slightly lower strength values accompanied by increased scatter at higher reinforcement levels. The observed behaviour may be associated with heterogeneous dispersion of ground GFRP fragments, reduced effective reinforcement length due to mechanical grinding, interfacial constraints, and defect formation within the press-consolidated structure. The findings provide insight into the structure–property relationships of recycled composite systems based on heterogeneous textile-derived polymer blends. Full article

The clothing and textile industry is under increasing pressure to comply with European sustainability directives, including the European Strategy for Sustainable and Circular Textiles, the Circular Economy Action Plan, and the revised Waste Framework Directive, effective October 2025. While global interest in sustainable textile practices grows, limited research has examined clothing consumption and disposal behaviors in Greece, particularly through the lens of practice theory. This study addresses that gap by exploring the dynamics of these practices using a structured questionnaire distributed online via Google Forms in 2024 with 250 valid responses. Chi-square (χ²) tests and regressions analyses were used to assess associations among certain categorical variables. Our findings reveal that older consumers tend to spend more on clothing and show a preference for fast fashion. Frequent shoppers also lean toward fast fashion, yet they demonstrate greater concern for material composition. Higher sustainability awareness is associated with a preference for purchasing fewer garments or opting for higher-quality items. Notably, discomfort with recycled materials predicts reluctance toward industrial recycling and reinforces the tendency to choose durable clothing that lasts longer. Full article