Bacterial cellulose (BC) nanofibers are addressed within a unified, quantitative process–structure–property engineering framework that follows the material logic from raw feedstock, through green processing, to structure, properties, and functional applications. Upstream biosynthesis variables (strain, carbon source, culture mode, and oxygen transfer coefficient, kLa) are reframed as structural design levers that set the crystallinity index (CI, 80–90
The use of advanced polymer-matrix composites continues to grow in the aerospace industry as technology advances. Void defects are among the most critical manufacturing-induced imperfections affecting the structural integrity of glass fiber-reinforced polymer (GFRP) composites. This study presents a comprehensive experimental evaluation of the influence of void content on the mechanical properties and fatigue performance of GFRP laminates. Specimens with controlled void fractions were fabricated by systematically varying processing parameters, enabling a direct correlation between void content and composite performance. Mechanical characterization was conducted through tensile, flexural, and interlaminar shear tests, while fatigue behavior was assessed under cyclic loading conditions. Microstructural analysis using optical and scanning electron microscopy was employed to investigate void morphology and distribution, and their roles in damage initiation and propagation. The results demonstrate that increasing void content significantly degrades stiffness, strength, and interlaminar properties, with pronounced reductions observed beyond a critical void threshold. Fatigue life was found to be highly sensitive to the presence of voids, as voids act as stress concentrators that accelerate crack initiation and growth under cyclic loading. Furthermore, the study highlights the interaction between void size, shape, and spatial distribution in governing failure mechanisms. The findings provide valuable insights into defect tolerance limits and underscore the need for stringent process control in composite manufacturing. This work contributes to the development of more reliable predictive models and improved quality standards for high-performance GFRP structures.
The increasing need for sustainable, lightweight and multifunctional materials has boosted the creation of natural fiber-reinforced polymer composites (NRF) with increased mechanical and vibroacoustic functions. Sisal–maize hybrid polymer composites that are reinforced with natural seaweed bio-fillers were compression-molded in this study, and their mechanical, vibrational, and acoustical characteristics were systematically studied. The content of seaweed filler (0–8 wt
Herbal extracts possess antioxidant and broad-spectrum antibacterial activity, which can efficiently inhibit the growth of multiple pathogenic microorganisms. However, their inherent disadvantages, including poor aqueous solubility and inferior physicochemical stability, severely hinder their practical application. Herein, a co-loaded dual-network polysaccharide hydrogel was engineered to tackle these challenges. Baicalin (BA) was first encapsulated into cyclodextrin to yield a BA inclusion complex, which was embedded within a crosslinked hydrogel network built from chondroitin sulfate and carboxymethyl chitosan. Berberine hydrochloride (BH), a synergistic antibacterial candidate, was co-loaded in situ during hydrogel synthesis to attain combined antibacterial effects of baicalin and berberine hydrochloride. The antibacterial results confirm that the BH-BA inclusion complex effectively lowers the individual effective antibacterial concentrations of both agents, showing prominent synergistic activity against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive). The resultant hydrogel displayed enhanced structural stability, favorable mechanical properties, excellent biocompatibility, as well as pH-responsive drug release profiles. After incubation with the dual-network hydrogel, the survival rates of Escherichia coli and Staphylococcus aureus reached 12.67 ± 3.06
The effect of through-thickness ply sequence on the tensile behavior of 48 K large-tow carbon fiber-reinforced polymer (CFRP) laminates was investigated. Three symmetric laminates, [− 45/0/45/90]s, [45/−45/90/0]s, and [0/90/45/−45]s, were fabricated with identical ply orientations, ply contents, and total thickness. Quasi-static tensile tests, digital image correlation (DIC), fracture observations, and unit-cell finite element simulations were combined to characterize the mechanical response, strain localization, stress redistribution, and progressive damage evolution. The results showed that ply sequence had a limited influence on tensile stiffness but markedly affected tensile strength and elongation at break. The average tensile strengths were 487.18, 570.73, and 612.90 MPa, respectively, while the elongation at break increased from approximately 2.7
Fiber orientation plays a fundamental role in governing the load transfer efficiency and failure behavior of fiber-reinforced polymer composites, while nanoscale reinforcement offers an effective strategy for tailoring their mechanical response. In this study, the influence of fiber orientation on the tensile performance of neat and halloysite nanotube (HNT)-modified glass fiber-reinforced epoxy (GFRE) laminates was investigated. Bidirectional plain-woven E-glass/epoxy laminates were fabricated, and tensile specimens were machined at orientations of 0°, 15°, 30°, and 45°, with the orientation angle defined relative to a principal yarn direction of the woven reinforcement. The tensile response was evaluated in terms of ultimate tensile strength, elastic modulus, failure strain, and modulus of toughness. The results revealed that fiber orientation influenced the tensile response, with tensile strength decreasing from 136.80 MPa at 0° to 49.67 MPa at 45° for neat laminates. HNT modification increased the tensile strength by 20.13
This study investigates the effects of washing and pilling on the structural characteristics (number of wales and courses per centimeter, number of stitches per square centimeter, stitch length, mass per unit area, and thickness), mechanical (compressibility, thickness loss, and compressive resilience), and physical properties (surface electrical resistivity and water retention) of double-weft knitted fabrics produced from 20 × 2 tex organic wool yarn in 1 × 1 rib and Milano rib structures. The structural characteristics, mechanical, and physical properties were evaluated before and after washing and after 7000 rubs. The results show that knit structure, washing, and pilling significantly affect fabric performance. In both tested fabrics, washing caused shrinkage in both length and width directions, while pilling resistance decreased with increasing rubs, with identical pilling grades observed after 5000 and 7000 rubs (Grades 2 and 1, respectively). Washing and pilling altered the structural characteristics of both fabrics, leading to corresponding changes in mechanical and physical properties. In general, washing and pilling increased compressibility (except for the Milano rib after washing), thickness loss, surface electrical resistivity (except for the Milano rib after pilling), and water retention, while reducing compressive resilience (except for the 1 × 1 rib after washing). Pilling tended to improve the investigated properties in both fabrics. In contrast, washing deteriorated the properties of the Milano rib but slightly improved those of the 1 × 1 rib.
Estimation of the tensile strength and Young’s modulus of nonwovens is difficult owing to complex internal fiber entanglement. In the present study, we developed a property estimation model whereby a polyethylene terephthalate (PET) fiber web mixed with sheath–core fibers containing a polyvinyl butyral (PVB) polymer adhesive is heated. We found that increasing the sheath–core fiber mixing ratio steepened the stress–strain curve and increased the strength. When plotted against the square of the mixing ratio, which represents the fiber contact probability or “entanglement point density,” the tensile strength exhibited a linear relationship, whereas the Young’s modulus became saturated at approximately 64
This study investigated the effects of E-glass roving geometry, including linear density (TEX), fiber volume fraction (Vf), and matrix rheological properties, namely processing temperature (Tm) and melt viscosity (μm), on the tensile and knot performance of melt-impregnated thermoplastic composite ropes (TCRs). Composite ropes were manufactured using a laboratory-scale continuous melt-impregnation system. Three commercially available E-glass rovings (300, 600, and 1200 tex) and three thermoplastic matrices (PLA, TPU, and PETG) were used to produce nine rope configurations. A total of 154 mechanical test results were obtained to evaluate the ultimate tensile strength (UTS), knot tensile strength (KTS), and knot efficiency (RUTS). Lower-TEX rovings generally exhibited superior tensile performance, likely because of more effective impregnation and improved stress transfer. PLA-based ropes achieved the highest UTS (818.6 MPa at 300 tex) and KTS (253.1 MPa at 600 tex), whereas TPU-based ropes generally exhibited the lowest knot performance. Statistical analyses revealed that TEX and Vf primarily governed the UTS, whereas Tm, μm, and Vf significantly influenced KTS and RUTS. Increasing Tm improved RUTS, whereas increasing Vf reduced it, demonstrating the importance of adequate matrix content in the highly deformed knot region. Multi-response optimization, based on simultaneous maximization of KTS and RUTS, predicted an optimum at TEX=472.7 g/1000 m, Tm=230 °C, μm=1.32 Pa·s, and Vf=31.9
The epoxy-fiber composite laminates are found to have a high strength-to-weight ratio, enhanced fatigue strength, and better stiffness performance. However, weak interfacial bonding, improved moisture absorption, and brittle nature due to higher epoxy content limit the overall functional properties of the composites. The objectives of the present research are to produce and enhance the functional properties of the Kenaf (KF)–sisal (SF)–glass fiber (GF)-reinforced epoxy composite laminates fabricated with 3 wt
Electrospun biodegradable fibers incorporating natural antimicrobial agents have attracted increasing interest for applications in textiles, packaging, and biomedical materials. In this study, polylactic acid (PLA) fibers loaded with eucalyptus essential oil (EEO) were fabricated via electrospinning and systematically characterized for structural, thermal, mechanical, release, and antibacterial properties. The incorporation of EEO reduced solution viscosity and conductivity, resulting in a decrease in fiber diameter from 2.38 ± 0.67 to 0.79 ± 0.23 μm and the formation of partially flattened fiber structures. Encapsulation efficiency ranged from 66 to 82
With the increasing demand for large-scale carbon fiber-reinforced plastic (CFRP) structures in future mobility, wind energy, and aerospace applications, epoxy resin systems that maintain stable processability during long-duration manufacturing have become increasingly important. In this study, epoxy systems based on anhydride curing agents, including methyltetrahydrophthalic anhydride and methylhexahydrophthalic anhydride, and reactive diluents, including butyl glycidyl ether and phenyl glycidyl ether, were designed and optimized for pot life and glass transition behavior. To replicate the processing requirements of large-scale CFRP manufacturing, a minimum pot life of 5 h was set as the target processing window, based on the time required to reach a viscosity of 3000 mPa·s. CFRP specimens fabricated with epoxy systems stored for 5 h after mixing exhibited impregnation behavior comparable to that of specimens prepared under the initial condition, while micro-CT analysis confirmed that void formation was effectively suppressed. Consequently, the mechanical properties of the CFRP specimens were nearly retained even after 5 h of resin storage. These findings indicate that reactive diluent-assisted control of viscosity and pot life is an effective strategy for maintaining impregnation quality and suppressing internal defects during long-duration CFRP processing. This study provides practical design guidelines for epoxy matrix systems suitable for the reliable fabrication of large-scale CFRP structures.
The design and development of new organic semiconductors are essential for advancing organic electronic device applications. Despite remarkable efforts to improve charge transport and carrier mobility in organic field-effect transistors (OFETs), the performance of OFETs still lags far behind that of halide perovskite semiconductor counterparts. In this study, we investigated ammonium-based additives, including halide-based ammonium salts and organic cations, to enhance the performance of OFETs. Among the investigated additives, tetrabutylammonium chloride (TBACl) resulted in enhanced charge transport and device performance when incorporated into poly(3-hexylthiophene) OFETs. Specifically, the TBACl-based OFETs exhibited an optimized average field-effect mobility of 0.24 cm2 V−1 s−1 (best value ≈ 0.48 cm2 V−1 s−1), which was about 14
Color stripping of reactive-dyed cotton is essential for correcting faulty dyeings and supporting textile recycling; however, its optimization is complicated by strongly nonlinear, dye-chemistry-dependent responses that conventional response surface methodology (RSM) cannot always capture. In this study, Gaussian process regression (GPR) with a Matérn 3/2 automatic relevance determination (ARD) kernel was applied to the alkaline–reductive color stripping of cotton fabric dyed with a bifunctional (BF) and a vinyl sulfone (VS) reactive dye, using a four-factor rotatable central composite design (30 runs per dye type). Across all six response–dye combinations, GPR outperformed second-order RSM in leave-one-out cross-validation, with predictive R2 improvements of up to +0.898; notably, the BF K/S model improved from a negative RSM predicted R2 (− 0.541) to +0.357. Where R2 remained modest, the mean absolute error was limited to 4.9–11.6
Heat and moisture are simultaneously generated during human activity, and evaporative heat loss becomes essential for comfort in warm environments; therefore, transport through voids of textiles must be understood at the structural level. This study uses parallel PET yarns as a controlled system to isolate yarn-scale effects and aims to quantify how packing factor, yarn density, filament number, filament denier, and twist govern moisture resistance under ISO 11092 skin-model conditions. Moisture resistance (Ret), water–vapor permeability (Wd), and heat flux were measured with a sweating guarded hotplate, and a fiber-level two-dimensional representative cross-section of the yarn–air array was built in COMSOL from measured yarn width, thickness, and packing factor, coupling solid heat transfer with diluted water–vapor transport using test-consistent boundary conditions and validated by experimental results. The results show that higher packing factor or higher yarn density reduces the connectivity of inter-filament voids, weakens the vapor-related convective component, and increases Ret; changes in filament-scale geometry mainly shift the balance between conduction and vapor-related transport when packing factor is similar; and twist further tightens the inter-filament void structure and strengthens these trends. Overall, the combined experimental–numerical approach links standard Ret measurements to fiber-level structure and offers practical guidance for designing PET yarn systems with targeted moisture management.
In this study, the crashworthiness and deformation behavior of biomimetic multicellular energy-absorbing structures were experimentally investigated on specimens produced by the melt-casting (FFF) method. Three different internal geometries—hollow cylindrical tube, bamboo-inspired, and lattice-reinforced—were produced using PLA, CFPLA, and GFPLA materials. Force–displacement curves were obtained through quasi-static compression tests; peak force (PCF), mean crushing force (MCF), energy absorption (EA), specific energy absorption (SEA), and collision force efficiency (CFE) were evaluated. The results show that both material type and internal geometry are decisive in crashworthiness. Bamboo-inspired structures exhibited the highest load-carrying capacity and energy absorption; approximately 9058 N MCF and 362 J EA were achieved in CFPLA specimens. Lattice-reinforced structures, especially in PLA material, showed more stable and incremental deformation behavior, with continuously increasing force curves indicating an effective densification mechanism. In CFPLA bamboo structures, the SEA reached its highest value with approximately 3484 J/g. GFPLA structures, on the other hand, exhibited poor performance due to diagonal buckling and irregular crushing. Overall, CFPLA provides high strength and energy absorption, while PLA offers more stable deformation. It was concluded that material selection and bio-inspired internal geometry design should be optimized together for optimum crashworthiness.
Composite fibers have attracted considerable attention owing to their large specific surface area, high porosity, and wide range of applications. In this paper, parallel composite fibers were prepared using the centrifugal spinning method. By analyzing the flow states of the spinning solution in the tank, a model of the radial resultant force acting on the solution at the outlet of the curved-tube nozzle was established. The study found that an excessive radial resultant force would damage the internal structure of the spinning solution and affect its stretching process as it enters the air after ejection, thereby influencing the quality of the final fiber morphology. To optimize the radius of curvature and bending angle of the curved-tube nozzle, the Sparrow Search Algorithm is employed, with the aim of minimizing the radial force of the spinning solution at the nozzle outlet to approximately zero. The optimized parameters identified are a bending angle of θ = 8.5° and a radius of curvature of R = 90 mm. The optimization results were validated through simulations and experiments utilizing five sets of curved-tube nozzles and one set of straight pipe nozzles with. The findings indicate that the composite fiber produced under the optimized conditions of a bending angle of 8.5° and a radius of curvature of 90 mm exhibits superior quality, no droplets on the surface, increased slenderness, and a more uniform diameter distribution.
Basalt fibre-reinforced epoxy composites have attracted increasing attention due to their excellent mechanical properties and chemical stability. However, their long-term durability in acidic environments remains a critical challenge, mainly due to interfacial degradation and fibre corrosion. To address this issue, this study proposes a synergistic surface modification strategy based on phytic acid and silane coupling agents, and investigates the influence of different phytic acid mass fractions on the corrosion resistance of basalt fibre composites. By characterising the surface morphology and elemental changes of the fibres, and combining this with tests on weight loss, electrical properties, mechanical properties and thermal stability, the synergistic modification effects and corrosion resistance mechanisms are comprehensively evaluated. The results indicate that the synergistic treatment with phytic acid and KH550 forms a stable complex film and a roughened structure on the fibre surface, effectively enhancing the bond strength between the fibres and the resin. Within the phytic acid mass fraction range investigated in this study, the composite exhibited the best acid resistance when the phytic acid mass fraction was 5
Medical masks (MMs) engineered to arrest hazardous airborne particles have experienced unprecedented demand following the coronavirus pandemic. To achieve elite protective thresholds against sub-micron bioparticles without inducing physiological breathing resistance, this study systematically integrates sustainable, post-consumer r-PET nanofibers into conventional nonwoven substrates via a three-stage optimization paradigm. In the first stage, functional nanofibers were electrospun onto polypropylene spunbond substrates utilizing r-PET concentrations of 10
