Fibers and Polymers最新文献

This study deals with the effects of recycled fiber usage and repeated laundering on air permeability and bursting strength properties of knitted fabrics in three basic fabric structures. For this purpose, recycled and virgin cotton and polyester fibers were used in various combinations in fabric production. Fabrics were subjected to repeated laundering under different temperatures and varying washing cycles and were dried with two different drying methods. It has been determined that knitted fabrics produced from recycled cotton containing polyester yarns give similar results to fabrics produced from virgin fibers in terms of air permeability and bursting strength. It was suggested to use recycled cotton/virgin polyester yarns in the knitted fabric production to achieve fabrics with high air permeability and compatible bursting strength values. Moreover, artificial neural networks were used to predict the air permeability and bursting strength of produced fabrics before and after repeated laundering. The obtained regression values were over 99% for both properties. Finally, it can be said that artificial neural networks could be used to predict air permeability and bursting strength of recycled cotton and PES-based knitted fabrics successfully. The results of this research can help manufacturers to choose the effectual fiber content and knitted fabric construction to achieve the intended performance properties in fabrics made from recycled and virgin cotton and polyester blends.

The performance of polymer composites not only addresses challenges in aircraft components but also contributes to industries, such as automotive, architecture, marine, military, sports, and construction. Current manufacturing techniques and the expertise of engineers are crucial in identifying the most suitable biomimetic materials for specific applications. Based on the current literatures, the study on integrating biomimicry into fiber-reinforced thermoplastic composites to develop aircraft radome is still lacking. Thus, this article reviews various types of composites used in aircraft manufacturing, emphasizing the potential of nature-inspired designs to enhance structural performance, with a particular focus on radomes, which protect radar equipment. Bio-inspired designs, shaped by millions of years of evolution, have proven to be highly effective in creating optimized, complex forms that complement the versatility of polymer composites. Given that many current aircraft components are made from metals with little or no shape optimization, applying biomimicry to aircraft radome design offers significant potential for creating lightweight, high-strength structures. The biomimetic approach using fiber-reinforced thermoplastic composites has emerged as a promising strategy for developing improved structural components, offering enhanced mechanical properties, reduced weight, and greater sustainability, paving the way for more efficient and environmentally friendly radome materials. A general overview of biomimicry in relation to aircraft radomes is provided, highlighting how composite materials have already contributed to successful innovations. The economic and environmental benefits of fiber-reinforced thermoplastic composites and biomimetic approaches are also discussed, with insights into materials that offer superior impact and chemical resistance at a lower cost.

Cancer is a leading cause of death in the world. Recent research studies have mainly focused on available treatments without problems. Recently, advances in nanotechnology have revolutionized the way that pharmaceuticals are given, reducing their negative effects. Electrospun nanofibers are unique among the colon-focused drug delivery technology in terms of their high biocompatibility and tunable drug-release profiles. The present study aimed to develop capecitabine (CPB)-loaded nanofibers (NFs) using a composite of polyvinyl alcohol (PVA) and polyacrylic acid (PAA) to achieve controlled release at colonic pH. A maximum drug-release rate of 91.92% was achieved with formulated nanofibers having a diameter of 591.38 nm. Results of in vitro release by NFs showed a burst release pattern at the initial stage followed by prolonged release for up to 20 h. In vitro cell cytotoxicity studies revealed high cytotoxicity of formulated NFs against HT-29 colon carcinoma. Formulated NFs also showed improved in vivo anti-cancer activity compared to free drug. Therapeutic efficacy of CPB NFs was superior compared to free drug in treating cancer in induced rats.

The cellulase enzyme has significant potential for applications in textile chemical processing, offering an environmentally friendly alternative to traditional chemical methods. In conventional enzymatic treatments, the enzymes act as biocatalysts and are typically discarded as effluent after completing their function. However, the single-use nature, high production costs, and limited biological activity of cellulase enzymes hinder their widespread commercial use in the textile industry. This study focuses on the immobilization of a commercial cellulase enzyme onto two distinct reversible soluble–insoluble polymers Chitosan and Eudragit S-100 for the recovery and reusability. Chitosan and Eudragit were chosen as support materials due to their pH-dependent soluble–insoluble properties. These properties allow them to act as homogeneous catalysts in their soluble phase during application (since textile materials are heterogeneous) and enable easy recovery in their insoluble phase for subsequent reuse. The immobilization process was optimized to achieve maximum enzyme activity with ideal enzyme loading percentages. After immobilization on chitosan, the cellulase retained 92% of its initial activity with a loading efficiency of 73.7%, while on Eudragit, it maintained 86.5% activity with a loading efficiency of 75.6%. Fourier-transform infrared spectroscopy (FTIR) was employed to confirm the successful attachment of the cellulase enzyme to the polymers. The immobilized cellulase demonstrated equivalent fading effects compared to the native cellulase in terms of color depth (K/S value) and color metrics (L*, a*, b*), while also reducing physical damage and back-staining—common issues in the traditional denim fading process. Scanning electron microscopy (SEM) and back-staining analyses of the denim samples provided further evidence of these benefits. Moreover, the immobilized cellulase maintained approximately 50% of its activity even after recovery from five denim washing cycles, showcasing the potential for reuse across multiple applications, particularly in textile processing. Thus, cellulase immobilized on chitosan and Eudragit S-100 represents a promising solution for the sustainable use of enzymes in the textile industry.

The natural fibers- and synthetic fibers-reinforced polymer hybrid composites have the advantages of low economical costs, good mechanical properties, low hygroscopicity and environmental sustainability. In this work, the flax fibers (F), basalt fibers (B) and polypropylene long fibers (PP) were used to prepare the wrapped yarns with hybridizing on yarn level. The polypropylene was a thermoplastic synthetic resin with excellent properties and low melting point. The wrapped yarns and PP yarns were further manufactured on the unidirectional fabrics by three weaving methods, which were laminated and hot pressed to prepare the hybrid composites. The effects of weaving methods, PP content and basalt fibers content in wrapped yarns on the mechanical properties of composites were investigated. It was found that the two PP yarns in the core of the hybrid-wrapped yarns helped the composites to attain good mechanical properties. As compared to 3F2PP composites, the tensile strength and flexural strength of 1F2B2PP hybrid composites were increased to 213.2% and 32.4%, respectively. As the basalt fiber content increased, the damage degree of the F/B composites reduced and the composites showed good impact energy absorption. The impact damage modes of the all F/B composites were mainly circular pit and band-shaped failure. Furthermore, the multi-scale finite element models of the hybrid composites were established to predict and simulate the mechanical properties.

As a natural macromolecular material, lignin (L) can be used as a filler to enhance the mechanical properties of poly (vinyl alcohol) (PVA). However, the blending system of L/PVA suffers from the poor compatibility of hydrophobic lignin and hydrophilic PVA. To address this issue, lignin was combined with PVA by acetalization synthesis at different reaction conditions. The obtained lignin–PVA (L–P) compounds were incorporated into 5% L/PVA gel-spun fibers as a second filler to enhance the filler/matrix compatibility. 5% L/PVA fiber reinforced by 5% L–P compound obtained with L/PVA mass ratio of 1:2, reaction temperature of 150 ℃, and reaction time 12 h exhibits the best mechanical properties. The optimal tensile strength is 925.23 MPa, Young’s modulus is 26.89 GPa, and toughness is 16.45 J/g. This work offers promising approach in developing compatible lignin/synthetic polymer systems for more sustainable high-performance fibers in the industrial or technical textile field.

Nowadays, manufacturing of ultraviolet (UV) protective textiles is quite interesting for the outdoor workers to protect their bodies from harmful radiation. Herein, for the first time, durable UV-protective cotton textiles were produced by modification with the mixed metal–Ce organic framework. Cotton was first interacted with 1,2,4-tricarboxybenzene-2,4-anhydride through benzylation reaction. The benzylated cotton (BTC–C = O@Cotton) was then reacted with two metal salts including Cerium salt to obtain Ce–M–BTC–C = O@Cotton. The estimated contents of Ce and the mixed metal within Ce–M–BTC–C = O@Cotton were 3.3% and 0.4%, respectively. The color of cotton was turned to bluish-green color, greenish-yellow color and reddish color after incorporation with Ce–Cu–BTC, Ce–Ni–BTC and Ce–Co–BTC, respectively. The all-modified fabrics exhibited UV-blocking character from good to excellent, depending on the inserted mixed metal. The measured UV-protection factor (UPF) was 34.7 (very good) for Ce–Cu–BTC–C = O@Cotton, 43.1 (excellent) for Ce–Ni–BTC–C = O@Cotton, 26.4 (good) for Ce–Zn–BTC–C = O@Cotton, and 33.3 (very good) for Ce–Co–BTC–C = O@Cotton. After 5 washing cycles, Ce–Ni–BTC–C = O@Cotton and Ce–Co–BTC–C = O@Cotton showed good UV protection. The mechanical properties of cotton textiles were not significantly affected after modification with Ce–M–BTC.

Delamination is one of the most typical failure modes of fiber-reinforced polymer composite laminates. Thus, investigating and improving the delamination behavior of these laminates are of vital importance. The present research discovers and investigates the role of the alkaline treatment of twill-woven flax fabric on the delamination resistance of flax fiber-reinforced epoxy composite laminates. Initially, flax fibers were treated with different sodium hydroxide solution concentrations (2–5–10%) for 2 h. The influence of alkaline treatment on fiber characteristics was evaluated by performing a single-yarn tensile test, scanning electron microscopy, and Fourier transform infrared spectroscopy analysis for treated and untreated flax fibers. The appropriate treatment condition was selected based on the properties obtained from the tests conducted on the fiber level. Subsequently, to discover the role of alkaline treatment on delamination resistance, flax fabric was treated with the selected treatment condition for further composite fabrication. The treated and untreated flax fiber-reinforced epoxy composites were fabricated using a hand lay-up technique followed by hot compression. Interlaminar shear strength, double cantilever beam, and end-notch flexural tests were carried out for treated and untreated composites to determine the effect of alkaline treatment on the delamination resistance. The results proved that the alkaline treatment of flax fabric significantly improved the delamination resistance of treated composite laminates compared to untreated ones. The interlaminar shear strength, the mode I interlaminar fracture toughness (propagation), and mode II interlaminar fracture toughness were improved by 27.3%, 14%, and 24.9%, respectively, for treated composite laminates compared to untreated ones.

Invasive alien plants are detrimentally displacing native plant species and pose a challenge in terms of how their overgrowth can be utilized effectively. In our study, the leaves of one of the world’s worst invasive species, Japanese knotweed, were used to produce a green natural dye. This dye was screen-printed onto various substrates, including cotton and polyester fabrics, commercial cellulose papers, and innovative papers made from the stems of Japanese knotweed. The printed substrates were evaluated using color measurements and fastness properties. The aim of the study was also to investigate the influence of additives in the printing inks, such as sodium carbonate, citric acid, copper and aluminum sulfates, on the color and fastness properties of the prints. The colors of the prints obtained varied, ranging from primarily yellowish-green to brownish-yellow with the addition of citric acid, orange-brown with sodium carbonate, orange-yellow with aluminum sulfate, and brown with copper sulfate. The prints had excellent fastness to dry rubbing and moderate fastness to light. The prints of lower and medium dye concentrations on fabrics had very good fastness to wet rubbing and wet ironing, and on cotton even good fastness to washing. The additives in the printing inks, such as sodium carbonate and metal sulfates, reduced the abrasion resistance of the prints on paper and the wet fastness of the prints on fabrics, but only the metal sulfates had a positive effect on the light fastness of the prints.

The main objectives of this study were to determine the optimum conditions of ultrasound (US) treatment to remove non-cellulosic biomass from barley straw residues, evaluate the effect of US treatment on the characteristics of acidified sodium chlorite (ASC)- or alkaline hydrogen peroxide (AHP)-bleached cellulose fibers, and compare the characteristics of cellulose fibers obtained after AHP and ASC bleaching. First, barley straw was treated by pressurized aqueous ethanol (PAE), then US treatment (400–1200 W/20 kHz/10–40 min) and ASC (1.7%/75 °C/2–6 h) or AHP bleaching (20%/75 °C/2–6 h) were performed to obtain cellulose fibers. Chemical composition, color, crystallinity, changes of functional groups, and morphology of cellulose fibers obtained were determined. The PAE treatment at 200 °C and 50 bar using 20% ethanol followed by US treatment at 1200 W/40 min removed most of the hemicellulose (92.9 (pm) 0.1%) and half of the initial lignin content, resulting in a cellulose-rich residue. Then, 99.1 (pm) 1.1 of hemicellulose and 86.5 (pm) 0.6% of lignin were removed after bleaching for 6 h. The highest purity of the barley straw cellulose fiber was 91.1 (pm) 2.3%, obtained after PAE + US + AHP bleaching for 6 h. At this optimum condition, the resultant cellulose fibers had crystallinity index of 38.9% without changing cellulose I structure. Morphology images revealed that the US treatment reduced the diameters of cellulose fibers to 3.54 and 4.42 (upmu)m after PAE + US + ASC and PAE + US + AHP bleaching for 6 h, respectively.