Fibers and Polymers最新文献

In this research, green dyeing treatment of wool fabrics was examined with natural dye extracted from Beta vulgaris (beetroot) with an ultrasonic-assisted method. Wool fabric samples were treated with ascorbic acid, sodium carbonate, and tannic acid with different concentrations and durations via the ultrasonic-assisted method before dyeing treatment. The usability of ascorbic acid, sodium carbonate, and tannic acid was investigated as a bio-mordant agent in the natural dyeing process. After the pre-treatment with different substrates, the samples were colored with the natural dye obtained from beetroot for 5 min with the ultrasonic-assisted method. The dyeing parameters’ effects were investigated on the colorimetric and fastness properties. According to the results, Fourier transform infrared spectra indicate that there are no important dissimilarities in the functional groups of wool fabric samples with the pre-mordanting process. The experimental results show that ascorbic acid, sodium carbonate, and tannic acid are used as bio-mordants. Furthermore, the pre-mordanting process, mordant agent type, mordant concentration, and mordanting time had an effect on the fastness and colorimetric behaviors of the samples. Color strength results demonstrated that ascorbic acid mordant improved the color strength of the samples (K/S increased from 3.51 to 4.63), attributing darker shades (lower lightness, L) to the wool fabric. The light fastness of samples improved from 1 to 2 with the use of ascorbic acid for 15 min mordanting time. Furthermore, the best results for color change, washing, and rubbing fastness were obtained by using tannic acid as a mordant and increasing the mordanting time. In addition, the following dyeing characteristics of wool fabrics are estimated using an artificial neural network (ANN) model. In accordance with the experimental outcomes, the suggested approach obtains regression values of more than 0.97 for all dyeing characteristics. As can be shown, the suggested approach is accomplished and can be utilized effectively for predicting colorimetric properties of wool fabric. It has been concluded that the ultrasonic-assisted method is an environmentally sustainable dyeing process of textile fibers, and bio-mordants have rendered the dyeing treatment greener and more sustainable.

Immobilization of metal–organic frameworks within the textile material for manufacturing protective textile materials is described as a challenging field of investigation. The point of novelty in the current approach is the preparation of technical textiles from viscose fabrics with photochromic/UV-protective/antimicrobial potentiality. Multi-finished viscose fabrics were prepared via cationization of viscose with sequential incorporation of Ln-BDCs (Eu-BDC and Tb-BDC) within viscose and cationic viscose in one-pot infrared-assisted technique. Herein, glycidyl trimethyl ammonium chloride (GTA) is uniquely exploited for the cationizing of viscose (GTA-viscose). The prepared photochromic fabrics showed a strong blue emission color (with excitation at λ_ex = 270 nm) under UV light. Successful domination of Ln-BDC which could be converted to lanthanide oxides consequently acted in stabilization of the fabrics at elevated temperature. Viscose fabrics modified with Tb-BDC showed higher thermal stability rather than those prepared with Eu-BDC. The evaluated UV-protection factor (UPF) for GTA-viscose (5.3) was largely enhanced to 39.5 after immobilization of Eu-BDC to be rated as very good affinity of blocking and was non-significantly lowered to 31.6 even after 10 washing cycles. Fabrics modified with Eu-BDC showed the highest antimicrobial action against bacteria and fungi. For GTA-viscose, after impregnation of Eu-BDC, the estimated inhibition zones were 16 mm, 15 mm, and 15 mm against E. coli, S. aureus, and C. albicans, respectively. In summary, the current approach demonstrates a unique technique for the preparation of multifunctional viscose with successive impregnation of either Tb-BDC or Eu-BDC to be exhibited with superior/durable photochromic/microbicide/UV-protective potency.

Triboelectric nanogenerator (TENG) is a promising energy harvesting device for harvesting renewable mechanical energy. Some materials used in triboelectric nanogenerator inevitably pollute the environment, so the development of green triboelectric materials has attracted widespread attention. Herein, we chose a non-toxic sodium carboxymethyl cellulose (CMC), which has poor tribopositive properties due to the carboxymethyl group contained in it. Thus, the tribopositive polarity of CMC is enhanced by doping hydroxy-rich polyvinyl alcohol (PVA) with strong electron-donating ability. Rough and porous CMC/PVA polymer blend films with strong tribopositive polarity and environmental friendliness were prepared by a simple physical blending strategy. The open-circuit voltage (V_OC) and short-circuit current (I_SC) were optimized to be 380 V and 49 µA, respectively, for a CMC/PVA mass ratio of 10:3, and the maximum power density of CMC/PVA-TENG was 1.32 mW/cm². This study provides a feasible approach for enhancing the tribopositive properties of materials by doping modification and the development of green triboelectric nanogenerators.

This study aims to optimize the thermo-mechanical properties and shape-memory effect of twisted nanofibrous yarns featuring a core–shell structure for potential integration into thermo-responsive smart textiles via conventional processing methods, such as weaving and knitting. Twisted shape-memory polyurethane (SMPU) yarns were fabricated utilizing a double-nozzle electrospinning device, and the effects of twist amount and core–shell configuration on their structural, mechanical, and shape-memory properties were examined. Morphological analysis confirmed the production of uniform yarns with twist angles ranging from 7 to 21°, while differential scanning calorimetry (DSC) thermograms indicated a transition temperature of approximately 44 °C. Increased levels of twist resulted in a significant rise in maximum stress, approximately 36%, alongside an enhancement in Young’s modulus of about 30%, with elongation at break values within the range of 140% to 180%. The thermo-mechanical behavior was assessed at 50% and 100% strain over three cycles, demonstrating improved shape fixity and recovery with increased twist levels. Although exhibiting lower mechanical strength, core–shell yarns displayed comparable shape-memory performance to their single counterparts. These findings contribute valuable insights into the optimization of electrospun yarn structures for enhanced shape-memory functionality in the context of smart textiles.

Biodegradable and affordable jute fibers absorb too much moisture, limiting their use. This research improves these fibers' moisture and water resistance to boost their utilization in many fields of application. The combined impact of chemical treatments and gamma irradiation improves moisture and water resistance properties. This study has determined the hydrophilicity of jute fibers by moisture content, moisture regain, water absorption, and water contact angle. Lower moisture levels make jute fibers stronger and less fragile. Jute fibers with reduced moisture content last longer and degrade less. The results indicate that the combined impact of irradiation and treatment on jute fibers resulted in a substantial increase in crystallinity, with a 31.27% increase. Additionally, the water contact angle significantly improved by 97%, and moisture contain, regain, and absorption reductions occurred by 60%, 63%, and 45%, respectively. These results suggest that the combined treatment significantly enhances the resistance to degradation of jute fibers, rendering them appropriate for use in humid environments. Jute fibers resist water better, improving dimensional stability and decreasing swelling and shrinkage. Reduced water absorption minimizes the risk of rot, mildew, and other biological degradation, extending the lifespan of jute fibers and products. Jute fibers resist water better, improving dimensional stability and decreasing swelling and shrinkage. Reduced water absorption minimizes the risk of rot, mildew, and other biological degradation, extending the lifespan of jute fibers and products. The treated fibers' moisture content and water absorption decreased significantly, improving dimensional stability, swelling, and biological deterioration. Water resistance increases fiber strength and durability, making them more suitable with composite materials and matrix bonding. Thus, treated jute fibers have improved mechanical characteristics and are better for high-performance applications, including textiles, construction, automotive, and environmental remediation. This modification method makes jute fibers useful in moisture-sensitive areas and sustainable and durable composite products.

Voids are a common defect in the manufacturing process of composite materials, which can reduce the mechanical properties of components. As an out-of-autoclave (OoA) technology, double-vacuum-bag (DVB) process can achieve low-cost manufacturing of composite materials with low void content. This paper investigated the effect of DVB process on void evolution and laminate properties during the curing process of composites. Different dwelling temperatures were applied, and a single-vacuum-bag (SVB) process was designed as the experimental control group. The curing cycles were completed and the laminates were rapidly cooled at selected time points. This work used a microscope to take cross-sectional images of samples, for statistical analysis of void morphology and void growth behavior. Besides, the density and fiber volume fraction of composite materials were measured by Archimedes method and combustion method. The experimental results show that as the curing cycle progressed, the void content of laminate produced by DVB process continued to decrease. Compared with the SVB process, the dual vacuum environment of the DVB process can timely discharge the stagnant air in the prepregs, thereby reducing the void content, which is at the same level of the composite materials manufactured by hot press with 0.6 MPa.

The poly(N-isopropylacrylamide) (PNIPAM) and cellulose acetate (CA) hydrogels were synthesized both in the presence and absence of N,N(^prime)-methylenebis(acrylamide) (NMBA) as a crosslinker. In the absence of NMBA, chemical crosslinking between PNIPAM and CA was demonstrated through free radical polymerization in acetone as the solvent, which has not been reported previously. These hydrogels exhibit smaller swelling ratios (2 to 22 water grams per xerogel gram) and larger compression moduli (from 0.39 to 2.62 MPa) than homo NIPA hydrogels. The lower critical solution temperature (LCST) values for these hydrogels increased from a range of 38 to beyond 50(^circ)C, depending on the CA concentration, and were higher than those of homo PNIPAM hydrogels. The formulations with 50 wt.% solids and 10 and 15 wt.% CA were barely affected in their swelling capacity when heated to 50(,^circ)C. These hydrogels were used to remove (hbox {Ni}^{2+}) from aqueous solutions. The adsorption capacity of these hydrogels ranged from 2 to 38 mg of (hbox {Ni}^{2+}) per gram of xerogel. The hydrogels synthesized without NMBA, exhibited typical PNIPAM LCST values, so they were used to adsorb (hbox {Ni}^{2+}) in solution and release it through the shrinkage process. When these hydrogels were reused four times in a row, the removal efficiency averaged 80% for each use and the overall remotion of (textrm{Ni}^{2+}) ranged from 97 to 151 mg per gram of xerogel. A potential application for cleaning polluted waters with (hbox {Ni}^{2+}) using PNIPAM-CA hydrogels is proposed herein, the cost of producing 1 g of these hydrogels in laboratory conditions is approximately 3 USD.

PET recycling is one of the most successful examples of polymer recycling. This study explored the mechanical recycling of PET bottles to produce industrial-grade PET fibers. Recycled bottle-grade PET (rPET) underwent solid-state polymerization at 230 °C to increase molecular weight (MW), followed by melt spinning at 300 °C. The weight-average MW reduction rates for virgin PET (vPET) and rPET with the same intrinsic viscosity were nearly identical. However, rPET fibers exhibited lower tensile strength and higher shrinkage rates than vPET fibers at the same draw ratio, primarily due to the presence of IPA units in the rPET structure. Using rPET polymerized to higher MW, the tensile strength of rPET fibers comparable to vPET fibers could be produced. Under UV irradiation, vPET and rPET fibers showed similar trends in tensile strength loss and MW reduction. UV irradiation predominantly affected the amorphous regions of the PET fibers, with minimal impact on the crystalline areas. This study demonstrates the feasibility of producing industrial PET fibers from rPET through SSP and melt spinning, offering a sustainable approach for high-value applications.

The current work describes the development of silica chitosan-guar gum blended nanocomposites (NCs) for the proficient removal of mercury (Hg²⁺) ions in aqueous solution at pH 12. The silica NCs were prepared by dispersing the as-synthesized silica nanoparticles (NPs) into the chitosan-guar gum (CS-GG) polymer blend matrix. The developed silica NCs were characterized by FTIR, SEM–EDS, XRD, TGA, and BET. The results confirmed the dispersion of silica NPs on the surface of the CS: GG blend resulting in silica NCs with improved thermal stability, and an enhanced specific pore surface area from 11.843 m²/g to 23.029 m²/g. The 2 and 5% silica NCs were used as an efficient adsorbent for the removal of mercury ions. The 2 and 5% of silica NCs showed a maximum removal efficiency of 88% and 79% for mercury ions, respectively. The adsorption process is best fitted with the Langmuir adsorption isotherm and pseudo-second-order kinetic model. The adsorbent proved to be economical with 72% of removal efficiency after five cycles using EDTA as a desorbing solution.

Fly ash (FA) is a byproduct of coal combustion, particularly in coal-based power plants. If FA is released into the open atmosphere or land, it becomes a major source of air and water pollution. The impact of FA on woven glass fabric-phenolic composite laminates is examined in the present study to find the application of FA in the structural field. The hand layup method is used to apply the FA-phenolic resin slurry (0 to 20 wt% FA) onto the woven glass fabric surface, followed by compression molding to get composites. The viscoelastic and static mechanical properties are evaluated using a dynamic mechanical thermal analyzer and a universal testing machine. The results show significant improvement in the flexural strength (26%), flexural modulus (31%), storage modulus (37.9%), and loss modulus (44%) of FA-GFRP composites. The interfacial interaction parameters such as entanglement density, reinforcing efficiency factor, and adhesion factors (b and C-factors) are also evaluated and correlated with other properties to understand the impact of FA on the performance of FA-GFRP composites.