Fibers and Polymers最新文献

This paper presents a novel deep learning-based (DL) approach to characterize short-fiber orientation in material extrusion large format additive manufacturing (LFAM). The method focuses on Acrylonitrile Butadiene Styrene (ABS) reinforced with short glass fibers 20%, a material widely used due to its enhanced mechanical performance. Traditional fiber orientation analysis, which relies on microscopy and manual image processing, is often costly and time-consuming. To address this, we developed Python algorithms to generate synthetic SEM-like images to train a Convolutional Neural Network (CNN). The proposed CNN accurately predicts the fiber orientation tensors directly from micrographs, with consistent results with conventional methods. The combination of synthetic data generation and deep learning provides a scalable and rapid alternative for fiber orientation analysis. This approach improves the analysis of fiber orientation in discontinuous composite materials and has the potential to be applied to additive manufacturing and other forming processes. This study demonstrates that combining deep learning with synthetic data generation provides an effective, scalable solution for fiber orientation analysis in LFAM, confirming that CNN-based methods can greatly improve material characterization. More accurate performance prediction and quality control could be achieved in fiber-reinforced additive manufacturing.

To address the challenge of optimizing flax fiber properties, this study developed an enhanced system based on the laccase-TEMPO (LT) system. By optimizing process conditions and introducing EDTA, an ELT system was formed to improve degumming efficiency, lignin removal, and fiber quality, while preserving fiber strength and whiteness, and minimizing damage to cellulose. Firstly, the problem of the low removal rate of pectin and hemicellulose by the ELT system was investigated by introducing a pectinase and hemicellulase compounding system. Subsequently, the optimal reaction conditions were determined using response surface methodology, which significantly improved the pectin removal rate and the weight loss rate. However, the lignin removal rate remained low. Finally, the best degumming effect was achieved by combining the ELT system with the enzyme compounding system. The final optimized process significantly increased the lignin removal rate and fiber quality, while improving fiber dispersion and surface smoothness. It was shown that the stepwise removal of hemicellulose, lignin, and pectin significantly promoted the overall degumming effect, especially the removal of pectin and hemicellulose promoted the lignin degradation better than the lignin removal promoted the other components.

Poly(isosorbide-co-1,4-cyclohexanedimethylene terephthalate) (PICT) exhibits a distinctive rose-patterned spherulitic morphology during crystallization, which has rarely been observed in bio-based polyesters. In this study, the origin of this unique morphology and its relationship with crystallization behavior were investigated. When crystallized at 200 °C for 20 min with 12 mol% incorporation of isosorbide (ISB), a biomass-derived rigid monomer, PICT formed rose-patterned spherulites. Thermal analysis revealed the presence of two distinct crystalline populations, namely stable and metastable forms, as evidenced by multiple melting endotherms similar to those observed in poly(1,4-cyclohexanedimethylene terephthalate) (PCT). The incorporation of ISB not only reduced the melting temperature and crystallization rate compared to PCT but also introduced dynamic heterogeneity into the system. Finally, for the first time, two-dimensional correlation spectroscopy (2DCOS) was employed along with the spin–lattice relaxation time obtained from solid-state cross polarization/magic angle spinning (CP-MAS) ¹³C NMR spectroscopy to determine the transitional sequence of the functional group inclusion/exclusion, and to reveal the motional capacity of each monomer arising from the environment-dependent relaxation behavior.

Graphical Abstract

High-performance and cost-effective polymer coatings are essential for developing advanced protective textiles that combine water resistance with water vapor permeability, meeting critical needs in diverse applications such as personal protective equipment. Nevertheless, existing polymer-based coatings can hardly achieve the satisfactory water vapor permeability required for high-performance protective textiles. Here, a network-structured polyurethane coating was developed on conventional textiles via a humidity-induced networking method based on the regulation of polyurethane concentrations in coating solutions to enable high breathability and waterproofness. By manipulating the polymer skeleton integrity and embedding depth of water droplets into coating solution through the adjustment of polyurethane solution concentrations, we endowed the polyurethane coating with interconnective porous architectures, on which waterborne fluorinated acrylates were coated to engineer magic coated networks with small apertures (pore size of 3.4 μm), open channels (porosity of 62.1%), and good hydrophobicity (water contact angle of 133.5°). The resulting network-coated fabric can achieve a fast water vapor transmission rate of 2764.7 g m⁻² d⁻¹ while resisting external liquid penetration with a hydrostatic pressure of 222.5 mmH₂O, making it promising for protective textiles. Our work can provide ample possibilities to develop future coated textiles for various applications in outdoor garments, protective gloves, and surgical gowns, among other things.

Graphical Abstract

A porous network coating was developed on conventional textiles via a humidity-induced networking method based on the regulation of polyurethane concentrations in coating solutions. The fantastic polyurethane network possessed interconnected channels and small apertures, and the resultant coated fabric was endowed with superior breathability and waterproofness for personal protective equipment.

Ultra-high molecular weight polyethylene (UHMWPE) ropes will suffer from severe tensile strength loss due to Norrish II type fracture of methylene chains under UV irradiation. In this study, nano-silica (SiO₂) was used to enhance the UV durability of waterborne polyurethane (WPU) coatings. Nano-SiO₂ was modified by KH550 to improve its compatibility with WPU, and best-performing formulation the tested candidates was selected for further study (27% WPU, 0.9% SiO₂). Through a comprehensive analysis combining accelerated UV aging tests, tensile wear tests, scanning electron microscopy (SEM) observations, differential scanning calorimetry (DSC) measurements, and Fourier transform infrared spectroscopy (FTIR) analyses, it is revealed that the UHMWPE ropes coated with WPU layer and SiO₂/WPU layer exhibit higher residual strength rates after 30 days of aging compared to the uncoated UHMWPE ropes. After applying the WPU coating, the residual strength rate of the rope increased from 28% before the coating to 35.7%, and the residual strength rate of the SiO₂/WPU coating further increased to 40.5%. SEM images show that during bending and wear, the SiO₂/WPU composite coating relies on nanoparticles to prevent cracks and reduce friction, and it has better wear resistance and fiber protection effects than pure WPU coating.

Healthcare environments face persistent challenges from contaminated textiles that facilitate the transmission of multidrug-resistant ESKAPK pathogens and fungal infections, contributing to high morbidity and economic burden. This study reports dual-spectrum antimicrobial nylon development through coating with silver nanoparticles (AgNPs) green-synthesized using Pandanus amaryllifolius extract (Pandan-AgNPs). UV–Vis spectroscopy confirmed nanoparticle formation with surface plasmon resonance peak at 464.1 nm. Transmission electron microscopy revealed spherical nanoparticles (21.86 ± 7.81 nm) with narrow size distribution, while zeta potential (-32.8 ± 0.81 mV) indicated good stability. In situ coating successfully deposited Pandan-AgNPs onto nylon, evidenced by distinct color shift (ΔE = 270.05 ± 10.75). Scanning electron microscopy and energy-dispersive X-ray spectroscopy confirmed successful nanoparticle deposition, while FTIR revealed Ag–O stretching vibrations and modifications in amide-associated functional groups, indicating chemical interaction between nanoparticles and the nylon matrix. Coating reduced water absorption capacity by 9.89% and increasing fabric density by 7.73%. Antimicrobial testing demonstrated > 98% reduction of all ESKAPK pathogens, lowering viable counts to 0.96–2.11 log₁₀ CFU/mL. Pandan-AgNPs coated nylon achieved > 99.9% inhibition against Aspergillus niger, Aspergillus flavus, Fusarium solani, and Talaromyces atroroseus. Durability analysis confirmed sustained antimicrobial activity, with > 96% bacterial reduction maintained after two washing cycles. Cytotoxicity assessment using 3T3/L1 normal cells indicated favorable biocompatibility, with 73–84% cell viability at 15.625–62.5 µg/mL and an IC₅₀ of approximately 92 µg/mL. These findings demonstrate that Pandan-AgNPs coated nylon provides broad-spectrum antimicrobial protection with excellent wash durability and minimal cytotoxicity, positioning it as a promising sustainable material for healthcare textiles.

Ceramic-faced ballistic armors have garnered significant utilization within the defense industry owing to their remarkable protective capabilities. However, a prominent issue encountered with these armors relates to the vulnerability of their ceramic front face due to direct contact with each other. Not only results in the fracturing of the initial impact zone, but also induces consequential harm to the surrounding material. Considering this challenge, an extensive review of existing literature was meticulously conducted to explore potential strategies for mitigating such damage. Drawing inspiration from the remarkable armor-like skin structure observed in armadillos, a novel design approach has been devised with the objective of enhancing the resilience of ceramic-faced ballistic armors. Additionally, the determination of the impact resistance of armor systems through experiments is very costly and time-consuming. Thus, this study focused on a cost-effective numerical and experimental analysis of a ceramic–steel armor system reinforced with carbon-epoxy composite wrapping. Ceramics were surrounded by carbon-epoxy composite material with different thicknesses (0.75, 1.0, and 1.5 mm) to reduce inter-ceramic contact damage. The results revealed that the composite wrapping around ceramics significantly reduced adjacent ceramic damage and improved energy absorption, structural integrity and overall ballistic performance. For unwrapped ceramics, all surrounding tiles were fractured with an average mass loss of 17.85%, while 1.0 mm composite wrapping limited the damage to only one ceramic, and 1.5 mm wrapping completely prevented adjacent ceramic fracture. Furthermore, steel plate deformation decreased by up to 1 mm, and the numerical predictions showed strong agreement with experimental findings.

Laminated composites frequently fail because of delamination, mainly owing to their characteristically weak resistance to interlaminar fractures. Enhancing the interlaminar fracture toughness of these materials remains a critical challenge in composite engineering. This study investigated the influence of incorporating glass nonwoven interlayer on the Mode I and Mode II fracture toughness of glass/epoxy laminated composites utilizing the double cantilever beam (DCB) and end-notched flexure (ENF) tests, respectively. For the fabrication of the composite specimens, woven glass fabrics with three distinct areal weights (200, 400, and 600 g/m²) were utilized along with glass nonwoven interlayers featuring two different areal weights (150 and 300 g/m²). The results revealed a significant enhancement in the fracture resistance of samples compared with the control samples without the interlayer. Specifically, the Mode I fracture toughness improved from 0.21 to 1.32 times, depending on the specific combination of layers. Similarly, including the nonwoven interlayer increased the Mode II fracture resistance from 1.44 to 10.55 times in the ENF test.

Graphical Abstract

Electrospinning is one of the techniques used for nanofiber fabrication, enabling the precise production of ultrafine nanofibers ranging from nanometers to micrometers in size. Compared to other nanofiber fabrication methods, electrospinning offers advantages such as a simple process, cost-effectiveness, and the ability to utilize a wide range of materials, making it highly versatile. Electrospun nanofibers exhibit a high surface area-to-volume ratio, a highly porous structure, tunable alignment and surface properties, and a structure that naturally mimics the extracellular matrix. These properties enhance their compatibility with biological environments, making them highly effective for biomedical engineering applications. Furthermore, the incorporation of nanoparticles and crosslinking agents can further enhance their mechanical strength, flexibility, biocompatibility, and antimicrobial properties, leading to extensive research in biomedical engineering fields. This review discusses the principles of electrospinning and provides a comprehensive overview of recent studies on the biomedical engineering applications of electrospun nanofibers, focusing on tissue engineering, wound dressing, drug delivery, and biosensors, while also exploring potential future research directions.