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In this study, a Ti3C2 MXene@g-C3N4 composite powder (TM-CN) was prepared by the ultrasonic self-assembly method and then loaded onto a carbon nanofiber membrane by the self-assembly properties of MXene for the treatment of organic pollutants in wastewater. The characterization of the TM-CN and the C-TM-CN was conducted via X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectrometer (FTIR) to ascertain the successful modification. The organic dye degradation experiments demonstrated that introducing an appropriate amount of Ti3C2 MXene resulted in the complete degradation of RhB within 60 min, three times the photocatalytic efficiency of a pure g-C3N4. The C-TM-CN exhibited the stable and outstanding photocatalytic degradation of the RhB solution over a wide range of pH values, indicating the characteristics of the photodegradation of organic pollutants in a wide range of aqueous environments. Furthermore, the results of the cyclic degradation experiments demonstrated that the C-TM-CN composite film maintained a degradation efficiency of over 85% after five cycles, thereby confirming a notable improvement in its cyclic stability. Consequently, the C-TM-CN composite film exhibits excellent photocatalytic performance and is readily recyclable, making it an auspicious eco-friendly material in water environment remediation. [ABSTRACT FROM AUTHOR]

Sulfur dioxide (SO2) pollution often poses a threat to the environment and human health, and there is an urgent need to develop flexible and convenient SO2 detection materials. MOF-5 treated with amino groups was added to polyvinyl alcohol, and then MOF-5-NH2/Polyvinyl alcohol (PVA) nanocomposite films were made by electrostatic spinning technology, and the MOF-5-NH2/PVA composite films such as mechanical and thermal stability and sensing of SO2 were systematically investigated. The results show that the MOF-5-NH2/PVA nanocomposite film has a certain tensile strength of 1.42 MPa, and the thermal stability of the MOF-5-NH2/PVA nanocomposite film is getting better as the ratio of MOF-5-NH2/PVA increases and the diameter of the fiber becomes smaller. Moreover, the produced composite film has fluorescence turn-on effect only for SO2, but not for other gases, showing a good specificity. Therefore, this study provides a new strategy for the preparation of highly sensitive and specific SO2 sensors. [ABSTRACT FROM AUTHOR]

Medical protective clothing is the first line of defense for medical staff, which makes the acquisition of protection and multiple function challenging. When it comes to contagious diseases, the physical properties of protective clothing are deemed the top priority and, subsequently, they have significant meaning for the structural design, production cost evaluation, convenient production, and innovation. In this study, nonwoven technology is employed to produce matrices in which mechanical properties are supported by Tencel fibers and recycled Kevlar fibers. Next, the electrostatic spinning is conducted to generate breathable and waterproof films. The nonwoven fabrics and membranes are combined to have diverse functions, forming lay-up compound matrices for medical protective clothing. Moreover, measurements are conducted to characterize the lay-up compound matrices in terms of the tensile strength, tearing strength, bursting strength, puncture resistance, stiffness, air-permeable property, surface resistance, comfort performance, sub-micron particulate filtration efficiency, and the penetration of synthetic blood. As for the nonwoven fabrics, the mechanical properties are significantly improved after Kevlar fibers are incorporated. The tensile strength is (62.6 ± 2.4) N along the machine direction (MD) and (50.1 ± 3.1) N along the cross machine direction (CD); the tearing strength is (29.5 ± 1.6) N along the MD and (43.0 ± 1.7) N along the CD; the bursting strength is (365.8 ± 5.0) kPa; and the puncture resistance is (22.6 ± 1.0) N. Moreover, the lay-up compound matrices exhibit a stiffness of (14.7 ± 0.2) cm along the MD and (14.6 ± 0.1) cm along the CD, a surface resistance of (2.85 × 109 ± 0.37 × 109) Ω, an air-permeable property of (45.4 ± 2.3) cm3/s/cm2, and sub-micron particulate filtration efficiency of over 98%. In the measurement for penetration of synthetic blood, the K40/PAN/TPU group prevents the synthetic blood from penetration. Hence, the incorporation of recycled Kevlar fibers and lay-up compound technique creates good physical properties, an appropriate comfort attribute, and functions, which suggests that this study provides a greater diversity and new concepts for the production of medical protective clothing. [ABSTRACT FROM AUTHOR]

With noise pollution and environmental pollution becoming more and more serious, it is very urgent to develop a kind of green, recyclable and degradable sound-absorbing material. In this study, the cellulose hydrogels were obtained by dissolving cotton staple as the main material, and the cellulose hydrogel was treated with directional freezing to solve the problem of irregular distribution and coexistence of open and closed pore structures in the traditional cellulose aerogels (CAs). CAs with regularly distributed and axially open porous structure were prepared to improve the sound-absorbing performance to meet application requirements. The sound absorption coefficient of directional cellulose aerogel reached 0.88 at 4500 Hz. In addition, CAs prepared in this study have low density (0.0554 g·cm−3), high porosity (89.32%) and good thermal stability. More importantly, directional cellulose aerogel in this study has good mechanical properties, with a compressive stress of 0.35 MPa at 70% strain. Therefore, the CAs treated with directional freezing has good prospects for application in the field of sound absorption. [ABSTRACT FROM AUTHOR]

Improvement of toughness is still a challenge for self-healing materials. Most of self-healing materials difficultly balance the mechanical and self-healing property. Here, a molecular design strategy of copolymer is proposed based on three combinations of reversible imine bond, chain motion and thermosensitive hydrogen bond together. The approach initially forms a co-continuous microphase separation structure and then cross-linked by aromatic imine via esterification reaction and Schiff base reaction, which features efficient self-healing, ultrahigh strength and toughness. The resultant elastomer exhibits a high stress at break (≈3 MPa) and high fracture strain (≈600 %). Additionally, the elastomer can reach 95 % self-healing efficiency after healing at 100 °C for 12 h. Extra reversible imine crosslinking displays a doubly promotion for fracture stress, and unchanging strain as well as 1times increase for self-healing efficiency, compared with merely chain motion and hydrogen bonding. This elastomer can be successfully spun into stretchable, conductive, self-healing filaments with core-shell structure by wet spinning and coating methods. It shows excellent corrosion resistance against NaCl, and conductive and self-healing property after coating by PANI polymer. This new type of self-healing polymer is promising to expand the application in future tissue engineering, soft robotics, and biomedical devices. [Display omitted] • Reversible imine was introduced into the copolymer in the form of crosslinking. • Imine crosslinking significantly improved the mechanical properties from 1 MPa to 3 MPa. • Imine crosslinking also significantly improved the comprehensive self-healing performance from 50 % to 95 %. • The self-healing copolymer was successfully refined by wet spinning. [ABSTRACT FROM AUTHOR]

At present, the thermoelectric eutectic tuning of thermoelectric materials remains a great challenge, so in this paper, polydopamine (PDA) was deposited on polypropylene (PP) to build up the gradient structure before spraying poly(3,4-ethylenedioxythiophene) nanowires (PEDOT nw), and then low-temperature interfacial polymerization technique was carried out to deposit PEDOT again to obtain the nano-phase-boundary-structured photothermoelectric fabrics. The presence of an energy filtration system at the interface of the two phases enhances the Seebeck coefficient, and hence the power factor, of the organic conducting polymer PEDOT. Subsequently, a photothermoelectric fabric (PA-PEDOT nw-Ty) has been obtained by introducing (polypyrrole) PPy as a photothermal layer, and finally a wet and dry photothermoelectric fabric device prepared by assembling with silver-functionalized polypropylene fabric (PP–Ag). The photothermoelectric fabric device can output 4.5 mV under 500 W of sunlight in the dry state, while the wet state photothermoelectric fabric device not only outputs 65.4 mV, but also evaporates 4 g of water within 1 h. Therefore, this study not only realizes the continuous conversion of photothermal to thermoelectric power, but also solar energy harvesting and solar vapor evaporation, which is a key step towards smart wearable products. The graphical abstract shows (a) a schematic illustration of the fabrication process of PEDOT nanowires, and (b) the chemical polymerization reaction of PEDOT. [Display omitted] • Firstly, PEDOT nw were successfully prepared based on the soft template method. • Secondly, increased Seebeck coefficient due to the energy filtering effect. • Thirdly, the wet and dry photothermoelectric fabric device was built. • Fourthly, the dry photothermoelectric fabric device can output 4.5 mV. • Fifthly, the wet photothermoelectric fabric device outputs 65.4 mV. [ABSTRACT FROM AUTHOR]

Bioelectric signals are an important factor that maintain cell functions and affect cell behavior. Conductive polymers (CPs) can facilitate cell activity and reinforce the signal transmission among cells, so CPs have triggered attention to the tissue regeneration. In this study, layer-by-layer strategy is employed and polyvinyl alcohol (PVA)/polylactic acid (PLA) braids are polymerized in polypyrrole (PPy) by ice template method. The stents that are deposited with PPy are then immersed in dopamine solution, which during polydopamine (PDA) is coated over the stents naturally. Finally, PDA is used as a template to form hydroxyapatite (HA) coating layer with the aim of electrochemical deposition. The test results indicate that PPy forms an even conductive network over the surface of braids while the electrochemically deposited HA made with PDA is adsorbed over the scaffolds in a needle pattern. According to the cyclic voltammetry measurement, the CV curves of HA/PDA/PPy scaffolds basically retain specified and thus the scaffolds possess stabilized electrochemical activity. At last, HA/PDA/PPy scaffolds are immersed in a simulated body fluid (SBF) for ten days and the surface is completely wrapped in HA, indicating an excellent biomineralization capability. MTT assay results suggest that the cell viability of composite scaffolds is improved by 188 %. This study provides a new perspective, a layer-by-layer structured bone scaffolds, broadening the application range of textile structure in the bone tissue engineering field. • This study broadens the application scope of textile structure in bone tissue engineering. [ABSTRACT FROM AUTHOR]

Abstract This study investigates the mechanical properties and damage behavior of flexible laminated composites. Needle punching is performed to combine woven Kevlar fabric and two nonwoven low-melting point polyester (LMPET) fabrics into a fabric interlayer. A sheet-extrusion machine is used to bond two thermoplastic polyurethane (TPU) sheets on each side of a fabric interlayer. The tensile strength, peel load, and static puncture resistance of the flexible laminated composites are evaluated, and the influences of needle-punching rates and depths are examined. Test results show that a high needle-punching rate or depth positively affects tensile strength by promoting fiber entanglement. The tensile strength of the 300-15 group reaches 24.70 MPa. Moreover, when the needle-punching depth does not exceed 11 mm, melted LMPET fibers help bond two-phase materials and thus increase the peel loads of the final composites. The 200-11 group has an optimal puncture resistance of 5.86 N. The combination of TPU sheets and woven Kevlar fabrics yields flexible laminated composites with good static puncture resistance. The results of this study can be applied to improve the performance of flexible laminated composites. [ABSTRACT FROM AUTHOR]

Laminated composites are subject to delamination. This study aims to address this drawback and obtain structurally stable, lightweight, thin laminated composites through a novel manufacturing method that involves blending thermoplastic polyurethane (TPU), low‐melting polyester (LMPET), and Kevlar. Nonwoven LMPET/Kevlar fabrics are first processed through a nonwoven technique and then combined twice with TPU sheets through the sheet extrusion method. The mechanical properties, thermal behavior, and combustion resistance of the laminated TPU/LMPET/Kevlar composites are then evaluated. Results show that LMPET fibers strengthen adhesion between TPU and nonwoven laminates, and the addition of a small amount of TPU increases the peeling strength of the laminated TPU/LMPET/Kevlar composites by 1.9‐fold. The distribution of Kevlar fibers enhances the tensile properties and flame resistance of the laminated composites. Specifically, the tensile strength of the laminated TPU/LMPET/Kevlar composites reaches 18.85 MPa, and their combustion rate is significantly reduced. The proposed manufacturing design efficiently reduces delamination, thus extending the application range of laminated TPU/LMPET/Kevlar composites. POLYM. COMPOS., 40:E550–E558, 2019. © 2018 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Nonwoven fabrics were used as reinforcement to laminated composites to improve the mechanical properties and damage behaviors. The needle-punched Kevlar/LMPET nonwoven interlayer and two TPU covers were combined via thermal bonding to form the laminated composites. Tensile strength, peel load, and static puncture resistance of the laminated composites were evaluated in terms of needle punching rate and depth of the nonwoven interlayer. Results showed that tensile strength and static puncture resistance depended on the needle punching depth, primarily on the tangled fiber points. The peel load was dependent on the needle punching rate, especially on the resulting melted LMPET fibers. The laminated composites exhibited desirable tensile properties, peel load, and static puncture resistance. [ABSTRACT FROM AUTHOR]

A highly efficient oligomer antimicrobial agent, polyhexamethylene guanidine hydrochloride (PHMGH), is added to mixtures of polyvinylpyrrolidone (PVP)/chitosan (CS) solution to form antimicrobial PVP/CS/PHMGH (PCP) nanofibrous membranes using an electrospinning method. The solution parameters including viscosity and electrical conductivity are used to characterize the formation of the nanofibers, and then the antimicrobial activity, biocompatibility, and cell activity of the resultant nanofibrous membranes are evaluated. The results show that with the addition of 0.1-0.2% PHMGH, the nanofiber diameter reduces by 5-12%. The antimicrobial activity result shows that the addition of 0.16% PHMGH in PVP/CS (PCP-1) decreases the minimum inhibitory concentration against Escherichia coli to 138.1 μg mL−1, a factor of 2-4 times lower than the PVP/CS (PC) nanofibrous membrane. The in vitro result shows that PCP nanofibrous membranes still have good cell compatibility. These electrospun PCP nanofibrous membranes can become excellent candidates to be used as antimicrobial wound dressings in the future. [ABSTRACT FROM AUTHOR]

Antibacterial materials are one of the important materials in our daily lives, especially in the medicine where antibacterial efficacy is indispensable. Moreover, the precise electronic instrument also requires highly electromagnetic interference shielding effectiveness (EMI SE) and as such to prevent mutual interference. Therefore, the acquisition of antibacterial property and EMI SE is essential. In this study, carbon nanotube (CNT) and triclosan (TCS) are used as conductive and antibacterial substances separately during the production of polypropylene (PP)-based antibacterial and conductive composite planks. The planks are tested for a series of physical property tests, EMI SE measurement, and antibacterial efficacy as related to the CNT content and the TCS content. The test results indicate regardless of whether it is CNT or TCS that is added, the planks exhibit good crystallinity. Furthermore, the presence of TCS contributes good antibacterial efficacy against staphylococcus aureus (S. Aureus), and the antibacterial efficacy effectuated by 0.1 wt% TCS also meets the related EU standard. In addition, the incorporation of both CNT and TCS adversely affects the EMI SE of the planks, but the resulting EMI SE remains to be between −15 dB and −20 dB. [ABSTRACT FROM AUTHOR]

This study adopts the melt compounding method to prepare /mutli-walled carbon nanotubes composites. The effects of different lengths of the mutli-walled carbon nanotubes on the isothermal crystallization behaviors, crystalline structure, and thermal stability of the polypropylene/mutli-walled carbon nanotubes composites are examined. The PLM results show that the combination of mutli-walled carbon nanotubes prevents the growth of polypropylene spherulites, and thus results in a small size of spherulites. The differential scanning calorimetry results show that the short (S-) or long (L-) mutli-walled carbon nanotubes can function as the nucleating agent of polypropylene, which accelerates the crystallization rate of polypropylene. Avrami theory analyses indicate that the addition of short-mutli-walled carbon nanotubes particularly provides polypropylene/mutli-walled carbon nanotubes composites with a high crystallization rate. The X-ray diffraction results show that the combination of mutli-walled carbon nanotubes does not pertain to the crystal structure. The TGA test results show that long-mutli-walled carbon nanotubes outperform short -mutli-walled carbon nanotubes in improving the thermal stability of polypropylene, and both can significantly improve it. [ABSTRACT FROM AUTHOR]

This study investigates the static-bursting and low-velocity impact property of the sandwich flexible composites. The sandwich flexible composites were composed of a three-dimensional (3D) fabric filled flexible polyurethane (PU) foam core, and two compound laminates as face sheet. Foam filled fabric reinforced sandwich flexible structure were designed to explore the effect on the static-bursting and low-velocity impact properties of the sandwich flexible composites. The results represent that the static-bursting strength of the foam could increase to 324% by reinforced with the filling-resistant 3D fabric. The fiber blending ratio of the filling resistant 3D fabric had a prominent influence on the static-bursting strength. Finally, the sandwich flexible composites with the filling resistant 3D fabric have great elongation that is favorable to the low-velocity impact strength. [ABSTRACT FROM AUTHOR]

This study investigates the influence of using zinc- (FZ) and nickel-coated (FN) 3D anode electrodes on the electricity yield of the two-chambered cubic microbial fuel cells (MFCs) in terms of the electricity production efficacy. Swine wastewater is used as seed inoculums matrix that serves as feedstock in the anode chamber. The FN-electrodes exhibit a high corrosion and anti-oxidation resistance in a 28-day oxidation process based on the EDX observation. In addition, a 3D electrode structure efficiently provides a large surface area that benefits electron transfer. FN-C3 electrodes have a voltage of 638.9 mV, a power density of 138.6 mW/m 2 , and chemical oxygen demand (COD) removal rate of 72.1%. [ABSTRACT FROM AUTHOR]

Polypropylene (PP)/multi-walled carbon nanotube (MWCNT) coated polyethylene terephthalate (PET) yarns are made into conductive woven/knitted fabrics. The fabric structure, tensile properties, static bursting properties, electrical resistivity, and electromagnetic interference shielding effectiveness (EMI SE) of the conductive fabrics are evaluated in terms of the content of MWCNT. The test results indicate that the conductive fabrics have optimal tensile strength and optimal bursting strength when composed of 2 wt% MWCNT. Moreover, the conductive fabrics have a stabilized structure as well as the lowest electrical resistivity and an optimal EMI SE when composed of 8 wt% MWCNT. Similarly, 3-layered conductive fabrics also have the maximum EMI SE. The conductive fabrics produced in this study have permanent electrical properties, a light weight, and flexibility. Moreover, their EMI SE reaches the protection level required by standard electronic devices. [ABSTRACT FROM AUTHOR]

The length of multi-walled carbon nanotubes (MWCNT) has an important influence on the properties of polymer/MWCNT composites. This study aims to examine the influence of the length of MWCNT on the mechanical properties, distribution, melting and crystallization behavior, and electromagnetic interference shielding effectiveness (EMI SE) of PP/MWCNT composites. The test results show that MWCNT of a short length contribute to better mechanical properties and have a better dispersion in the matrix. MWCNT also serve as a nucleating agent for PP, thereby increasing the crystallization temperature (T). In particular, short MWCNT provide PP/MWCNT composites with a greater degree of cyrstallinity. The conjunction of 8 wt% long MWCNT in PP/MWCNT composites results in an optimal electrical resistivity of 65.02 Ω-cm, and an average EMI SE of −29.47 dB. The polymer/MWCNT composites have properties that can be adjusted by using different lengths of MWCNT, which is advantageous for application in diverse products. [ABSTRACT FROM AUTHOR]

Self-healing is a fascinating property for materials, but it is still a challenge to simply, effectively and greenly prepare self-healing material. Here, a self-healing elastomer was fabricated by solubilization copolymerization of ethylene glycol methyl ether acrylate (MEA) and N-isopropylacrylamide (NIPAM). When NIPAM content was 40%, "strong condensed state" emerged and led to obvious microphase separation, which greatly improved stress to 3.5 MPa at break (≈650%). Meantime, because the condensed state was still weak in the copolymer, the dissociation and re-association could occur to improve self-healing performance. The copolymer had about 60% self-healing efficiency after 8h at 100 °C, and the actual stress was 2 MPa at break (≈500%). The copolymer with good solubility can be easily recycled and reprocessed. A wrinkled skin-core conductive filament also was prepared by wet spinning and stretching coating, which was conductive and stretchable. And the self-healing core can drive conductive PEDOT: PSS shell to re-touch after break. [Display omitted] • The solubilization copolymerization preparation is more simple, effective and green. • Microphase separation structure are formed by polymerizing monomer with micellar distribution. • NIPAM condensed state can achieve dissociation and re-association to improved self-healing performance. • Copolymers have good mechanical properties, self-healing properties, recyclability and secondary processability. [ABSTRACT FROM AUTHOR]

Polypropylene (PP) and styrene-ethylene-butylene-styrene triblock copolymer (SEBS) are blended with a weight ratio of 70/30 to serve as the matrices. The prepared polymer blends were evaluated by tensile, flexural, and Izod impact tests, as well as by differential scanning calorimetry (DSC), optical microscopy, and scanning electron microscopy. The optimal PP/SEBS matrices were then combined with graphene nanosheets (GNs) and carbon fibers (CFs) by a melt compounding method to form conductive polymer composites. The crystallization properties, tensile properties, conductivity, and electromagnetic interference shielding effectiveness (EMISE) of the composites were evaluated by DSC and tensile strength and conductivity tests. In PP/SEBS blends, the SEBS acted as the nucleating agent of PP, thereby increasing the crystallization temperature and accelerating the crystallization rate, without significant influence on the degree of crystallinity. An increase in SEBS loading is inversely proportional to the tensile strength, tensile modulus, flexural strength, and flexural modulus of the PP/SEBS blends, but is highly proportional to the impact strength. In addition, the tensile strength of the conductive PP/SEBS/GN conductive composites decreased with the increase in the amount of GNs, with a percolating threshold of approximately 1.6 vol%. A distinct synergistic effect of the GNs and CFs on the conductive PP/SEBS/GN/CF composites was not achieved until the total loading level was 15 wt%. Optimal conductivity and EMISE of the conductive PP/SEBS/GN/CF composites were achieved at GN/CF ratios of 10/5 wt% and 5/10 wt%, respectively. [ABSTRACT FROM AUTHOR]

This study examines how inter/intra-ply hybrid structures influence the impact load of sandwich-structured flexible composites determined by static or low-velocity impact tests. The flexible composites are composed of nylon/high-resilient non-woven polyester fabrics as the surface sheet and polyurethane foam as the core layer. The polyurethane foam layer has a specified thickness and density, while the surface layers comprise various fiber blending ratios, different blending methods, different lamination procedures and lamination orders. The test results show that the flexible composites have an optimal impact absorption of 1901 N for a static impact when the nylon/high-resilient polyester non-woven fabrics are composed of an inter-ply hybrid structure. In contrast, they have an optimal impact absorption of 8255 N for a low-velocity impact when the nylon/high-resilience polyester non-woven fabrics are composed of an intra-ply hybrid structure. [ABSTRACT FROM AUTHOR]

Lithospermum erythrorhizon has been proved to be anti-inflammatory, by recent studies. This study extracts L. erythrorhizon with ethanol at various solid–liquid ratios (1:4, 1:6, 1:8, and 1:12), extraction temperatures (40 °C, 50 °C, and 60 °C), and extraction times (4, 24 and 36 h) in order to determine the optimal parameters. The optimal parameters are extracted and condensed into L. erythrorhizon extract; then the antibacterial property and cell compatibility of L. erythrorhizon extract are evaluated with various concentrations of L. erythrorhizon extract solution and different weights of L. erythrorhizon extract powder, respectively. The concentrations of solution are 0.1 mg/ml, 0.5 mg/ml, 1.0 mg/ml, and 2.0 mg/ml and ethanol is chosen as the solvent, and different weights of powder are varied as 0.1 mg, 1.0 mg, 2.0 mg, and 10 mg. The cell viability test and animal study are performed on L. erythrorhizon microcapsules. The experiment results show that sodium alginate/pectin L. erythrorhizon (SPL) microcapsules possess a 120-hour drug release. The results of cell viability and animal study show that the L. erythrorhizon microcapsules (SPL) have good cell viability (99%) and can help in the wound healing process (the wound size reduction reaches 91.3% on Day 11). [ABSTRACT FROM AUTHOR]

In order to create polymer composites that can shield machine and instrument casings from electromagnetism and to reclaim waste material, this study melt-blended impact-resistant polypropylene (PP) chips, carbon fibers (CFs; 5, 10, 15, or 20 wt%), and glass fibers (GFs; 0, 5, 7 wt%). This process used a single-screw extruder to make electrically conductive composites. The resulting composites were then evaluated in terms of mechanical properties, electromagnetic shielding effectiveness (EMSE), and surface resistivity. According to experimental results, an increase in CF content increased PP/CF composites’ tensile strength to 29.31 MPa and flexural strength to 38.93 MPa but decreased the impact strength to 49.04 MPa. When the CFs were increased to 15 wt%, the EMSE and surface resistivity of PP/CF composites were above 20 db and 3.3 × 103 Ω/square. For PP/CF/GF composites, with an increase in GF content, the EMSE decreased and the surface resistivity increased. [ABSTRACT FROM PUBLISHER]

Abstract: This study presents a green method to synthesize antibacterial silver nanoparticles (Ag NPs) employing chitosan and silver nitrate. Chitosan acted as dispersion and stabilizing agent. Ag NPs were radiated by UV ray to improve their reaction efficiency. UV–vis spectra showed that absorption peak of Ag NPs occurred at 402nm wavelength. TEM observed that the average size of Ag NPs was 25–30nm. XRD revealed that crystalline peak was Ag (111), Ag (200) and Ag (220). The synthesized Ag NPs had antibacterial activity against Escherichia coli. [Copyright &y& Elsevier]

Electrospinning is an efficient method of producing nanofibers out of polymers that shows a great potential for the filtration territory. Featuring water-soluble chitosan (WS-CS), a low-pollution process and a self-made needleless machine, PVA/WS-CS nanofibrous membranes were prepared and evaluated for nanofiber diameter, bacteriostatic property, filtration efficiency, pressure drop, and quality factor. Test results indicate that the minimal fiber diameter was 216.58 ± 58.15 nm. Regardless of the WS-CS concentration, all of the PVA/WS-CS nanofibrous membranes attained a high porosity and a high water vapor transmission rate (WVTR), with a pore size of 12.06–22.48 nm. Moreover, the membranes also exhibit bacteriostatic efficacy against Staphylococcus aureus, an optimal quality factor of 0.0825 Pa−1, and a filtration efficiency as high as 97.0%, that is 72.5% higher than that of common masks. [ABSTRACT FROM AUTHOR]

Modern technology has advanced swiftly, and thus, people have higher and higher demands for functional textiles. In order to have textiles with electromagnetic shielding effectiveness (EMSE) and far infrared emissivity, in this research, we fabricated three types of bamboo charcoal/metal (BC/M) complex yarns with metal wires as the core yarn and bamboo charcoal textured yarn as the wrapped yarns, with a rotor twister machine. Two manufacture parameters for the complex yarns were rotor speed (8000 rpm) and wrapped number of the BC/M complex yarns (4 turns/cm). BC/M complex woven fabrics were made of cotton yarn (warp yarn) and BC/M complex yarns (weft yarns), using a loom machine. The surface resistivities of BC/M complex woven fabrics were first measured. Then, EMSE evaluation was performed to test BC/M complex woven fabrics with different lamination angles. The BC/M complex woven fabrics exhibited higher surface resistivity than other woven fabrics by 1.71 × 1010 Ω/Sq; and the EMSE was 50–60 dB when the lamination number was 6 at incident frequencies between 1.83 and 3 GHz, which was satisfactory. [ABSTRACT FROM PUBLISHER]

Wood plastic composite, known as green composite, combines natural vegetable fibers and plastic and thus acquires the properties of both. In this study, coir was subject to alkali treatment to eliminate pectin, hemicelluloses, fat and impurities. Alkali treatment reduces the weight of coir and the greater the concentration and longer the alkali treatment time, the greater is the loss of coir fibers. This study uses coir fibers and polypropylene to make wood plastic composite. Alkali treatment can increase the mechanical property of the resulting wood plastic composite. In particular, the optimum parameters of the treatment are 17.5 wt% for 1 h. As is demonstrated by scanning electron microscope images, methylmaleic anhydride-graft-polypropylene improves the interface binding force between the coir and polypropylene. [ABSTRACT FROM AUTHOR]

Poly(lactic acid) (PLA) twisted yarn was braided into a 6-layered, hollow, cylindrical braid on a 16-spindle braid machine. The PLA braid was then placed inside a β-TCP tube, forming the PLA/β-TCP complex tube which imitates the porous structure of sponge bone. Different components and structures were studied to determine the best bone molding material. The β-TCP tube was created by sintering TCP powder mixed with stearic acid in a ratio of 1:1.5 to form a highly porous and well-structured tube with interconnected pores; its resulting porosity was 85.8 ± 0.93%. The PLA/β-TCP complex tube was implanted in a rabbit's femur and after 3 months a marrow cavity was discovered at the tube's core. New bone was also observed, regenerating around the PLA braid within the PLA/β-TCP complex tube. [ABSTRACT FROM AUTHOR]

Laminated composites have been commonly applied to all fields. When made into laminated composites, Kevlar woven fabrics are able to provide the required functions. In this study, two types of TPU are incorporated to improve the intralayer features of Kevlar/TPU laminated composites. Hence, the Kevlar/TPU laminated composites consist of firmly bonded laminates while retaining flexibility of the fabrics. Being the interlayer of the laminated composites, the TPU layer provides adhesion while strengthening the tensile property, dynamic puncture resistance, and buffer strength of Kevlar/TPU laminated composites. The test results indicate that with a blending ratio of two types of TRU being 85/15 wt%, the Kevlar/TPU laminated composites exhibit a tensile strength of 18.08 MPa. When the stacking thickness is 1 mm, the tensile strength is improved to 357.73 N with the buffering strength reaching 4224.40 N. Notably, with a thickness being 1.2 mm, the laminated composites demonstrate a dynamic resistance being 672.15 N. In the meanwhile, functional Kevlar fabrics are allowed to keep the fiber morphology owing to the protection of TPU composite films. Considering the composition of protective gear, Kevlar/TPU laminated composites possess a powerful potential and are worthwhile exploring. [ABSTRACT FROM AUTHOR]

Abstract: Polymer products belong to petrochemical compounds and uneasily degrade in the natural environment. Besides, the process of extraction and purification of oil consume resources, energy and result in environmental pollution. For recycling of plastic wastes and environmental preservation, this study focused on blending and reprocessing of polyester (PET) and polypropylene (PP) due to their large amount of disposal. In this study, thermoplastic composites were made from blending virgin PET and PP pellets with the bamboo charcoal by melt compounding and then injection molding. The mechanical properties and functions of these composites were investigated. The compositions of blended ratio were also studied in this work. The results show that the mechanical properties of the PET/PPext (extrusion grade polypropylene) composites were better than that of the PET/PPinj (injection grade polypropylene) composites with 10 and 20% of polyester composition. After three extrusion processes, the tensile strength, impact strength and flexural modulus of the PET/PPext composites were still, respectively, maintained around 32MPa, 35J/m and 2000MPa. While the content of polyester is 30%, the serious phase separation between PET and PP resulted in poor mechanical properties of the PET/PPext composites. While the content of polyester was 20%, the mechanical properties of the PET/PPinj composite were not significantly influenced by the addition of bamboo charcoal. [Copyright &y& Elsevier]

Abstract: During the fabricating of extended-PTFE (ePTFE) fabrics, we found that the ePTFE yarn is easy to be collapsed because of excluding each other by electrostatic friction of the ePTFE yarn during warping procedure. Therefore, the single warping was adopted in the experiment and we also added some anti-electrostatic solution and enhanced the humidity of warping to decrease the influence. During weaving process, the small fell of cloth (32mm) was carried out and the warp level angle (312°) was advanced to prevent the crinkle of fabric caused by shrunk weft yarn. In the investigation of the physical properties of ePTFE fabric, we found that both of the acid-resistance and heat-resistance are really excellent. Even if the ePTFE fabric is used in the environment temperature of 300°C for 1h, there is still no change in the mechanical properties. Heat shrinkage has rarely different at temperature of 100 and 200°C, but it changed obviously at the temperature of 300°C. In this study, when the fabric structure was 3/1 right twill and the weft density was 20picks/cm, it will have the optimum breaking strength. [Copyright &y& Elsevier]

Abstract: Polymer, ceramic and metal are wildly applied in orthopedic and dental materials. However, most metal including titanium, titanium alloy and 316L stainless steel do not posses bioactivities to bond with bone tissue. For improving this weakness, we incubated titanium wire and 316L stainless steel fiber into the simulated body fluid (SBF) after alkaline and thermal treatments to form a bone-like apatite layer on it. With the reaction, the coating was formed on the surface of metal and it can induce apatite nucleus appear on the surface. The surface appearance was observed and the chemical constitution of bone-like apatite was examined. As the result show, when the titanium wire and 316L stainless steel fiber treated with 5M NaOH aqueous solution, subsequently heated at 400°C and soaked into SBF at a temperature of 80°C increase the possibility of nucleation of considerable quantities of bone-like hydroxyapatite. We also found the main components of both the HA structures were Ca and P, and the percentage Ca/P were 1.69 and 1.1, which is similar to that of a natural bone. [Copyright &y& Elsevier]

This study aims to develop nanofibrous membranes where Eucalyptus globules oil (EGO) is wrapped in polyvinyl alcohol (PVA). The EGO-based nanofibrous membranes are then evaluated for the protection against Forcipomyia taiwana (F. taiwana). In the first stage, the PVA solutions are formulated with different concentrations and are measured for viscosity and electrical conductivity. In the next stage, PVA solution and EGO are blended at different ratios and electrospun into PVA/EGO nanofibrous membranes (i.e., EGO-based repellent). In this study, a PVA concentration of 14 wt% has a positive influence on fiber formation. Furthermore, the finest nanofibers of 291 nm are presented when the voltage is 15 kV. The repellent efficacy can reach 80% in a 60-min release when the repellent is composed of a PVA/oil ratio of 90/10. To sum up, the nanofibrous membranes of essential oil exhibit good repellent efficacy against F. taiwana and significant slow-release effect, instead of adversely affecting the cell viability. [ABSTRACT FROM AUTHOR]

Combining photodynamic antimicrobials with nonwovens is prospective. However, common photosensitizers still have drawbacks such as poor photoactivity and the inability to charge. In this study, a photodynamic and high‐efficiency antimicrobial protective material was prepared by grafting bis benzophenone‐structured 4,4‐terephthaloyl diphthalic anhydride (TDPA) photosensitizer, and antimicrobial agent chlorogenic acid (CA) onto spunbond‐meltblown‐spunbond (SMS) membranes. The charging rates for ·OH and H2O2 were 6377.89 and 913.52 μg/g/h. The light absorption transients structural storage remained above 69% for 1 month. High electrical capacity remained after seven cycles indicating its rechargeability and recyclability. The SMS/TDPA/CA membrane has excellent bactericidal performance when under illumination or lightless conditions, and the bactericidal efficiency of Escherichia coli and Staphylococcus aureus reached over 99%. The construction of self‐disinfection textiles based on the photodynamic strategies proposed in this paper is constructive for expanding and promoting the application of textile materials in the medical field. [ABSTRACT FROM AUTHOR]

This study introduces functional composite boards, combining nano carbon yarns, stainless steels, and far-infrared (FIR) polypropylene (PP). Stainless steel filaments are wrapped in nano carbon fibers to form yarns, which are then woven into knitted fabrics. These fabrics are laminated at various angles and combined with FIR powder and PP pellets to create functional slabs. These slabs are hot-pressed to form the composite boards. The boards are tested for various properties, leading to the identification of optimal parameters: 2.5 wt% FIR powder content and a lamination angle of 0°/45°/90°. The optimal boards demonstrate high tensile strength, impact resistance, bending capacity, EMI shielding, and FIR release. Thus, the boards with these parameters offer the best performance. [ABSTRACT FROM AUTHOR]

Metal oxide semiconductor (MOS) gas sensing materials have high operating temperatures and often use rigid materials as substrates, making them difficult to be widely applied in the field of wearable electronic devices. In this work, the sheath-core structure electrospun nanofiber core-spun yarn (ES-PY) was prepared using the coaxial electrospun yarn technology, and then the poly (dopamine) was polymerized on its surface to obtain the poly (dopamine) nanofiber core-spun yarn (PDA-PY). ZnO/SnO 2 /Mn metal oxide semiconductor nanoparticles (ZS/Mn-NPs) were synthesized via a two-step hydrothermal process by doping Mn into ZnO/SnO 2. These were subsequently loaded onto the surface of PDA-PY to produce the yarn sensor (ZS/Mn-PY).The combination of the nano-size effect of the nanofibers and the doping-promoting effect of the Mn-doped metal oxide semiconductor further increases the adsorption sites of the gas molecules so that the sensor exhibits excellent gas sensitivity to ammonia (NH 3), with a response up to 13.13 (R a /R g) in an ammonia atmosphere at a concentration of 100 ppm, and still up to 2.61 when exposed to an ammonia atmosphere at a concentration as low as 10 ppm at room temperature. In addition, it retains the excellent flexibility and strength of the core yarn. And provides a simple and effective method for preparing flexible textile gas sensor. [ABSTRACT FROM AUTHOR]

This study aims to develop coronary artery stents using a spray-coating method. Chitosan is coated onto the polyvinyl alcohol (PVA) fibers in order to form PVA/CS coronary artery stents. The formation of chitosan is evaluated, examining the influences on the PVA/CS stents. The stents are evaluated using surface observation, scanning electron microscope (SEM) observation, thickness measurement, mesh size measurement, braid angle measurement, strut coverage rate measurement, compression strength test, and Fourier transforms infrared spectrometry (FTIR). The test results show that the spray-coating method successfully coats chitosan layer over the PVA/CS stents without sealing the mesh. Moreover, a longer spray coating span improves the compression resistance and maintains the perfect biocompatibility of the PVA/CS stents. This study successfully prepares PVA/CS coronary artery stents that are in a reticular, tubular manner, and coated with a well-formed chitosan layer. [ABSTRACT FROM AUTHOR]

In this study, three differently composed polyurethane (PU) composites are developed and then compared with the pure PU foam in terms of combustion resistance and mechanical properties using the compression test, the drop-weight impact test, the horizontal burning test, and the sound absorption test. Flame-retardant fabric (FRF)-PU is composed of PU foam that is enclosed with two cover sheets of FRFs. FR-PU10 is composed of PU foam that contains 10 wt% of flame-retardant agents. FRF-PU10 is composed of PU foam containing 10 wt% of flame-retardant agents and enclosed by two covers sheets of FRFs. Based on the test results, both FR-PU10 and FRF-PU10 are structurally stabilized and have good combustion resistance. The sample using FRFs as cover sheet had the same combustion resistance property and better compression resistance as the sample using flame-retardant agent. The carbonized layer extinguishes the alighted samples and stops the fire spread right after they are out of the source of fire, suggesting the FRF-PU10 is flame retardant. In addition, FRF-PU10 is easier to process and healthier because of the low use of flame retardants. Therefore, in this study, we proposed PU foam composites have good mechanical and flame-retardant properties and are a suitable candidate for productions of vehicles, plants, construction, and staple merchandises. [ABSTRACT FROM AUTHOR]

Here, we designed a flexible, highly adaptive, self-Standing photoelectrochemical (PEC) aptasensor for Aflatoxin B1 (AFB1) detection based on BiOBr/TiO 2 hierarchical nanofiber membranes (NFM) with a 3D pinecone-like structure by integrating sol-gel electrospinning with the successive ionic layer adsorption and reaction (SILAR) method. The uniformly deposited BiOBr nanosheets could not only enlarge the surface area but also expand the light absorption range of TiO 2 NFM. Owing to the pinecone-like and hierarchical structure, the photo-generated carriers of BiOBr/TiO 2 NFM could be separated quickly and efficiently, which was contributed to obtain a larger and more stable photocurrent intensity. The photocurrent intensity of 6-BiOBr/TiO 2 NFM was 12.1 times of pristine TiO 2 NFM and 3.4 times of pure BiOBr, respectively. The constructed flexible and self-Standing PEC aptasensor has achieved AFB1 detection in tomato samples with good repeatability, specificity and sensitivity. Under the optimized conditions, a wide linear range (0.001–400 ng mL−1) and a detection limit of 0.12 pg mL−1 (S/N = 3) were obtained for AFB1 determination. This design principle provided a neo-idea for development of flexible and self-Standing PEC aptasensor. [ABSTRACT FROM AUTHOR]

This study is conducted with an attempt to explore the influences of PEO (2, 4, 6 wt%) and Salvia miltiorrhiza Bunge (100, 125, 150, and 175 mg/mL) over the antibacterial and other performances of wound dressings. The PEO/ Salvia miltiorrhiza Bunge mixtures are formed into wound dressings via the electrospinning. The scanning electron microscope (SEM) observation, fiber diameter analysis, water contact angle measurement, and antibacterial assay are performed to investigate the properties of wound dressings. The properties of nanofiber membranes are correlated with PEO concentration, and the antibacterial property of nanofiber membranes is dependent on the Salvia miltiorrhiza Bunge concentration, which makes the optimal Salvia miltiorrhiza Bunge/PEO ratio being 175/6. The optimal diameter of nanofibers is 239.00 ± 361 nm while the maximal diameter of inhibition zone is 11.50 mm. To sum up, the Salvia miltiorrhiza Bunge-loaded wound dressings exhibit the optimal water contact angle, antibacterial property, and nanofiber diameter. [ABSTRACT FROM AUTHOR]

Swine wastewater has a high concentration of organic matter, suspended solids, and higher ammonia nitrogen, odor, complex polluting ingredients, and large emissions. A two-chambered cubic microbial fuel cell ( MFC) was used to evaluate the effect of a novel three-dimensional ( 3D) electrode made of 3D iron composites and 3D stainless composites on the electricity generation. Swine wastewater with a total chemical oxygen demand ( TCOD) of 3688 ± 300 mg/L was used as the feedstock in the anode chamber. The MFC reactor was incubated with an initial pH of 7.0 in an air shaker with a temperature of ~35°C and 100 rpm in the fed-batch mode. A fixed external resistance ( R) of 100 Ω was connected between the electrodes, and the closed-circuit potentials of the MFCs were recorded every 5 min. The results showed that using an iron-carbon fiber composite 3D electrode resulted in a peak electricity generation of 321 mV on the first 2 days and maintained a stable voltage of 163 mV during the second to sixth days. The COD removal efficiency could reach 75%. Using a stainless-carbon fiber 3D electrode could generate a peak voltage of only 29.5 mV and a stable voltage of 15.2 mV with a COD removal efficiency of 54%. [ABSTRACT FROM AUTHOR]

The rapid development of wireless communication and electronic equipment requires active measures to eliminate electromagnetic radiation hazards. Based on the layered assembly strategy, MXene-based composite fabric with multiple functional layers was prepared by combining two-dimensional transition metal (MXene) with PP substrate by a simple solution dipping method. PP substrate endowed pure MXene film certain mechanical properties, and polydopamine modification on the surface of PP enhanced the bonding fastness between the substrate and MXene layer. The silicon-containing hydrophobic layer imparted hydrophobic properties to the conductive fabric, thus ensuring the stability of the conductivity of the MXene layer when used in complex environments. The results shown that the conductivity and electromagnetic shielding effectiveness (EMI SE) of the composite fabric increased with the increased in impregnation times. When the impregnation times were three, the conductivity and EMI SE of the composite fabric were 6.54 S/cm and 32.57 dB, respectively. After hydrophobic treatment, the contact angle of the composite fabric was 140.49°. In addition, the average EMI SE and shielding efficiency still reached 25.12 dB and 99.69%. The excellent EMI shielding capability coupled with favorable bendability endows MXene-based composite fabric to be an alternative choice in electronics, aerospace and smart wearables. [ABSTRACT FROM AUTHOR]

Melt-blown nonwoven fabrics for filtration are usually manufactured using polypropylene, but after a certain time period the middle layer of the mask may have a reduced effect on adsorbing particles and may not be easily stored. Adding electret materials not only increases storage time, but also shows in this study that the addition of electret can improve filtration efficiency. Therefore, this experiment uses a melt-blown method to prepare a nonwoven layer, and adds MMT, CNT, and TiO2 electret materials to it for experiments. Polypropylene (PP) chip, montmorillonite (MMT) and titanium dioxide (TiO2) powders, and carbon nanotube (CNT) are blended and made into compound masterbatch pellets using a single-screw extruder. The resulting compound pellets thus contain different combinations of PP, MMT, TiO2, and CNT. Next, a hot pressor is used to make the compound chips into a high-poly film, which is then measured with differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). The optimal parameters are yielded and employed to form the PP/MMT/TiO2 nonwoven fabrics and PP/MMT/CNT nonwoven fabrics. The basis weight, thickness, diameter, pore size, fiber covering ratio, air permeability, and tensile property of different nonwoven fabrics are evaluated in order to have the optimal group of PP-based melt-blown nonwoven fabrics. According to the results of DSC and FTIR measurements, PP and MMT, CNT, and TiO2 are completely mixed, and the melting temperature (Tm), crystallization temperature (Tc) and endotherm area are changed accordingly. The difference in enthalpy of melting changes the crystallization of PP pellets, which in turn changes the fibers. Moreover, the Fourier transform infrared (FTIR) spectroscopy results substantiate that PP pellets are well blended with CNT and MMT, according to the comparisons of characteristic peaks. Finally, the scanning electron microscopy (SEM) observation suggests that with a spinning die temperature of 240 °C and a spinning die pressure lower than 0.01 MPa, the compound pellets can be successfully formed into melt-blown nonwoven fabrics with a 10-micrometer diameter. The proposed melt-blown nonwoven fabrics can be processed with electret to form long-lasting electret melt-blown nonwoven filters. [ABSTRACT FROM AUTHOR]

This study uses a reactive extrusion for the grafting of maleic anhydride on polylactic acid in order to form polylactic acid grafted maleic anhydride that serves as a compatibilizer between polylactic acid and carbon fiber. The effects of different ratios of the free radical initiator to maleic anhydride as well as the amounts of polylactic acid grafted maleic anhydride on the mechanical properties, interfacial compatibility, thermal behaviors, and electrical properties of the polylactic acid/carbon fiber composites are discussed. The test results indicate that using polylactic acid grafted maleic anhydride as compatibilizer improves the interfacial compatibility of polylactic acid/carbon fiber composites, which in turn contributes to a high electrical conductivity and the electromagnetic interference shielding effectiveness, while decreasing the surface resistance and increases. In addition, the amount of polylactic acid grafted maleic anhydride has a positive influence on their tensile properties, flexural strength, and impact strength. The differential scanning calorimetry results indicate that a high polylactic acid grafted maleic anhydride content is also conducive to crystallinity, but is not in related to the melting temperature. According to the scanning electronic microscope observation, the fractured composites that are inflicted by an impact have considerably few traces of the fibers being pulled out, which is ascribed to polylactic acid that can completely enwrap carbon fiber. Therefore, the incorporation of polylactic acid grafted maleic anhydride is proven to strengthen polylactic acid/carbon fiber composites, exemplified by their improved interfacial compatibility and properties. [ABSTRACT FROM AUTHOR]

In this study, a porous composite foam with excellent adsorption property toward Pb2+ was obtained by combining modified polyester (PET) fabric with polyurethane (PU) foam and using melamine and bentonite as modifiers. The effects of bentonite content on the adsorption and mechanical property of the modified fabric were studied. Based on the position of the modified PET fabric in porous PU foam, the P‐PU and PU‐P‐PU composite foams are prepared, and the effects of the fabric‐foam interface structure on the mechanical properties and adsorption properties were investigated. Effects of different experimental conditions such as pH value, contact time and initial dye concentration on adsorption capacity were investigated, and kinetic and isotherm of adsorption were used to analyze the adsorption mechanism of Pb2+ by foam. It was found that the porous composite foam have outstanding mechanical property and high adsorption efficiency. The adsorption was well‐described by pseudo‐second‐order kinetic and Langmuir isotherm models. Thus, the porous composite foam has great promise in removing heavy metal ions from water. [ABSTRACT FROM AUTHOR]

In this study, nonwoven fabrics, rigid polyurethane foam (RPUF), Basalt woven fabrics, and an aluminum foil film mold are used to produce multi-functional composite sheets with flame-retardant, sound-absorbing, and electromagnetic-shielding functions. The nonwoven layer is composed of Nomex fibers, flame-retardant PET fibers, and low-melting-point (LMPET) fibers via the needle rolling process. The optimal Nomex fiber/flame-retardant PET fiber/LMPET fiber (N/F/L) nonwoven fabrics are then combined with rigid polyurethane (PU) foam, Basalt woven fabric, and an aluminum foil film mold, thereby producing nonwoven/rigid polyurethane foam/Basalt woven fabric composite sheets that are wrapped in the aluminized foil film. The test results indicate that formed with a foaming density of 60 kg/m3 and 10 wt% of a flame retardant, the composite sheets exhibit electromagnetic interference shielding efficacy (EMI SE) that exceeds 40 dB and limiting oxygen index (LOI) that is greater than 26. The efficient and highly reproducible experimental design proposed in this study can produce multifunctional composite sheets that feature excellent combustion resistance, sound absorption, and EMI SE and are suitable for use in the transportation, industrial factories, and building wall fields. [ABSTRACT FROM AUTHOR]

As a replacement for mineral materials, geotextiles have been pervasively used in civil engineering so as to provide separation and filtration. This study aims to recycle Kevlar selvages for the preparation of nonwoven geotextiles. The effects of fiber types and manufacturing processing are examined in terms of pore size, water permeability, and shear resistance (bursting strength, and puncture strength). The test results and statistical analyses indicate that a combination of 20 wt% Kevlar fibers, 60 wt% three-dimensional crimped polyester (PET) fibers, and 20 wt% low-melting-point PET (LMPET) fibers creates geotextiles that have a small pore size, good water permeability, and good shear resistance. These geotextiles prevent soil loss, and have greater water permeability and a higher resistance to sharp objects. [ABSTRACT FROM AUTHOR]

This study proposes the composites with a sandwich structure that is primarily made by the multi-step foaming process. The staple material is polyurethane (PU) foam that is combined with carbon fibers, followed by a Kevlar woven fabric. The composites are evaluated in terms of puncture resistance, buffer absorption, and electromagnetic wave shielding effectiveness (EMSE). The manufacturing process provides the composites with a stabilized structure efficiently. Serving the interlayer, a Kevlar woven fabric are sealed between a top and a bottom layer consisting of both PU foam and an aluminum film in order, thereby forming five-layered composites. Namely, the upper and lower surfaces of the five-layered sandwiches are aluminum films which is laminated on a purpose for the EMSE reinforcement. The test results indicate that the PU foam composites are well bonded and thus acquire multiple functions from the constituent materials, including buffer absorption, puncture resistance, and EMSE. There is much prospect that the PU foam composites can be used as a protective material in diverse fields owing to a flexible range of functions. [ABSTRACT FROM AUTHOR]

Metal–oxide–semiconductor gas-sensing materials, due to their high operating temperatures and often using rigid materials as substrates, limit their application in the field of wearable electronic devices. In this work, a skin–core structure electrospun nanofiber core-spun yarn (ES-PY) with polypropylene yarn (PY) as the core yarn and polyvinylidene fluoride (PVDF) nanofibers as the wrapping layer was prepared by a coaxial electrospinning nanofiber yarn-forming technique. The yarn sensor (ZS-PY) was prepared by compounding it with ZnO/SnO2N–n-type metal–oxide–semiconductor heterojunction gas-sensing material prepared by a two-step hydrothermal method. The obtained yarn sensor utilized the synergistic effect of ZnO and SnO2, and the nanostructure effect of nanofibers and exhibited excellent gas-sensing performance for ammonia (NH3). The response to 100 ppm NH3 can reach 60.41%, with rapid response/recovery time even when exposed to an ammonia concentration as low as 10 ppm at room temperature. In addition, it has excellent gas selectivity and stability. Meanwhile, the yarn sensor retains the mechanical strength and flexibility of its core yarn, so it can be processed into specific electronic textiles using various textile molding techniques and is expected to be applied to the development of wearable smart textiles. [ABSTRACT FROM AUTHOR]

Conventional personal protective equipment is usually made in multilayer stacks, and appears clumsy and uncomfortable, offering limited protection. In recent years, a newly-developed nanosuspension, shear thickening fluids (STFs), has been commonly applied to buffer and shock absorption. In this study, nonwoven fabrics are impregnated with 30 wt%, 35 wt%, or 40 wt% STF in order to strengthen the interaction among fibers. The resultant STF composite nonwoven fabrics are observed for their morphology, and tested for their tensile strength, tearing strength, bursting strength, and dynamic impact resistance, thereby examining the damage resistance of the materials. The SEM images indicate that the fibers are adhered with a tremendous amount of silicon dioxide (SiO2) particulates with a rise in the STF concentration, due to which the smooth fibers become rough. Moreover, the mechanical test results indicate that a rise in the STF concentration improves the frictional force during the relative motion of fibers, which subsequently mechanically strengthens the STF composite nonwoven fabrics. The dynamic impact test results show that when the STF concentration increases from 30 wt% to 35 wt%, the materials exhibit dynamic impact strength that is significantly improved to 51.9%. Nonetheless, significant improvement in dynamic impact strength is absent when the STF concentration increases to 40 wt%. To sum up, a critical value of STF concentration has a positive influence over the mechanical strengths of STF composite nonwoven fabrics. [ABSTRACT FROM AUTHOR]