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Wound healing requires a contamination-free, sterile, and breathable environment. However, to develop an ideal wound dressing with all these functionalities simultaneously poses significant challenges. In this study, we designed a wound dressing that mimics the structure of skin with good breathability and protective functions. The wound dressing consists of a hydrophilic Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P34HB) membrane coated with zinc oxide nanoparticles and a hydrophobic polyvinylidene fluoride (PVDF) membrane. Meanwhile, plasma treatment was also utilized to bond the two layers, resulting in an enhancement of 60 % in mechanical properties. The crosslinked fibrous membranes exhibited uniform stress distribution when stretching. Due to the unique structures of the wound dressing, it demonstrates wound exudate management, antibacterial functions, and hemostatic properties. The hydrophobic layer guided wound exudate towards the hydrophilic layer and the zinc oxide nanoparticles acted as a barrier against external bacteria and released zinc ions to inhibit bacterial growth in the exudate. Moreover, the water vapor transmission rate (WVTR) was measured to be over 86.55 kg/m2/day, the hemolysis rate was 2.38 %, and an impressive 81.98 % healing rate was recorded during in vitro wound healing. This skin-mimicking wound dressing shows great potential as a promising solution for the therapy of chronic wounds and infections.

Due to the frequent occurrence of food safety problems in recent years, healthy diets are gradually receiving worldwide attention. Chemical pigments are used in smart food packaging because of their bright colors and high visibility. However, due to shortcomings such as carcinogenicity, people are gradually looking for natural pigments to be applied in the field of smart food packaging. In traditional smart food packaging, the indicator and the packaging bag substrate have different degrees of toxicity. Smart food packaging that combines natural colorants and cellulose-based hydrogels is becoming more and more popular with consumers for being natural, non-toxic, environmentally friendly, and renewable. This paper reviews the synthesis methods and characteristics of cellulose-based hydrogels, as well as the common types and characteristics of natural pigments, and discusses the application of natural colorants and cellulose-based hydrogels in food packaging, demonstrating their great potential in smart food packaging.

With the aggravation of environmental pollution and the worldwide epidemic of infectious diseases, there is a higher demand for air filtration materials to intercept fine particulate matter and capture biological pollutants. Polypropylene (PP)/polycarbonate (PC) blends were melt blown and electrospun with polytetrafluoroethylene (PTFE) on their surfaces. The PP/PC/PTFE membranes structure with micro-nanostructure was constructed through the melt-blown layer with micron structure and the electrospun layer with the nanostructure. Carboxymethyl chitosan (CMCS) was loaded onto the surface of the PP/PC melt-blown layer. The synergistic effect of micro-nanostructure and CMCS can effectively capture PM2.5 and make the composite membrane have excellent antibacterial performance. The inhibition rates of PP/PC/PTFE composite membrane loaded with 5% CMCS against Staphylococcus aureus and Escherichia coli reached 81.54% and 86.1%, respectively. The filtration efficiency of PP/PC/PTFE composite membrane loaded with 5% CMCS is close to 100% for 0.25 μm particles, and the average filtration efficiency for 0.200–4.596 μm and 0.200–2.500 μm particles is 97.31% and 97.27%, respectively. After washing and drying five times, the corresponding inhibition rate only lost 16.52% and 4.24%. The micro/nano structure composite membrane prepared in this study has good antibacterial performance, high filtration efficiency, good stability, and is an excellent antibacterial high efficiency air filter. It provides a new idea for the preparation of air filter fiber composites.

The shortage of water resources and the aggravation of water pollution have become global environmental problems. The improvement of the separation performance and flux is still a key challenge that restrict the preparation of high-performance filtration membrane. The gradient structure fibrous membranes were designed and prepared using electrospinning nanofiber and polypropylene/low-melt- point polyester (PP/LPET) micro-fibrous and reinforced via needle-punching and hot-pressing. And the as-prepared membrane was functionalized and directly decorated by dopamine copolymerizes. The novel gradient membrane turned from a hydrophobic state to hydrophilic state, and had excellent mechanical and water transmission properties. Mostly importantly, the as-prepared hydrophilic gradient membranes showed durable oil-fouling repellency and the separation efficiency of oil/water mixture approximate 99% and the flux reach 10,278 ± 1512 L m−2 h−1. This method provides a feasible solution to overcome the high filtration resistance of electrospinning nanofiber membrane, as well as for the preparation of low-cost and high-performance composite membranes and structural regulation of functional membranes.

This study explores a new type of nanofiber membrane using water-soluble polymer material, polyethylene glycol (PEG), as the main raw material. The membrane is prepared by combining PEG with polyvinyl pyrrolidone (PVP) and urushiol (UR) through electrospinning. The research findings demonstrate that the degradation rate of the nanofiber membrane can be controlled by adjusting the UR content, enabling the production of wound dressings that match the required healing time. Additionally, the addition of UR provides the nanofiber membrane with certain antimicrobial effects against Escherichia coli and Staphylococcus aureus. When combined with nano zinc oxide (ZnO), the antimicrobial effect of the nanofiber membrane reaches 99%. Furthermore, cytotoxicity experiments conducted on the nanofiber membrane meet the relevant standards. The results of this study provide a reliable option for researching and developing PEG materials with improved drug delivery effects. The nanofiber membrane possesses the characteristic of regulating degradation rate and shows potential for application in the field of wound healing, providing support for wound repair and tissue remodeling.

Photoelectrodes constructed with photoactive materials are of great significance for the performance of photoelectrochemical (PEC) sensors. In this study, a facile and efficacious non-enzymatic glucose sensor based on the Cu2O/TiO2 heterojunction was successfully constructed for quantitative determination of glucose concentration. The Cu2O/TiO2 heterojunction was generated by first obtaining TiO2 nanofibers via electrostatic spinning and high-temperature calcination, and then synthesizing Cu2O nanoparticles via a one-step hydrothermal reaction. By introducing the narrow band gap semiconductor Cu2O, the defect that pure TiO2 could not absorb visible light was improved, resulting in the improved photoelectrochemical performance of the composite material compared to the single component semiconductor. The sensor exhibited favorable PEC non-enzymatic glucose sensing performance under simulated sunlight irradiation with a wide linear response range from 1 mM to 14 mM (R2 = 0.9991) and a low detection limit of 14.4 μM (S/N = 3), along with good selectivity, stability and reproducibility. This also provided more ideas and possibilities for preparing photoelectrode materials by constructing heterojunctions.

In order to prepare a new high-performance and flexibility stab-resistant composite material, one type of high-toughness and high-strength hydrogel is combined with aramid fabric. In this paper, the nanocomposite (NC) hydrogels are prepared using Pluronic F127 Diacrylate (PF127DA) as the crosslinking agent, acrylamide as the monomer and nano-silica as nano additive. The influence of the addition amount of nano-silica on the toughness and strength of nano-composite hydrogels is discussed. The strength and toughness of the NC hydrogels with nano silica are higher than that of the acrylamide hydrogel without nano particles. The NC hydrogel with the best strength is made as a composite with aramid fabric and the effect of nanocomposite hydrogel on the stab resistance of the stab-resistant composite material is studied. The research shows that the stab resistance performance of the composite material prepared by aramid fabric and nanocomposite hydrogel is effectively improved in comparison with aramid fabric, and the yarn pulling force is also improved. The composite material with high stab resistance can be used as the stab-resistant layer of armor, cut-resistant gloves and stab-resistant base material of shoes. This work provided a possibility for preparing a kind of lightweight composite material with high stab resistance.

With the rapid development of wearable electronic products and smart devices, there is an urgent need to develop efficient electromagnetic interference (EMI)shielding materials to eliminate the resulting radiation pollution. Herein, hydrophobic and multi-responsive conductive composite film with core-shell structure and sandwich structure are constructed via simple in-situ polymerization and dip coating methods. The thin silicone coating can enhance the bonding fastness of the substrate and the conductive functional layer and endow the composite film excellent waterproof performance. The composite film with a thickness of 45 μm exhibits outstanding electrical conductivity of 62.15 S/cm and EMI shielding effectiveness (EMI SE) of 37.71 dB. Surprisingly, the composite film also exhibits good waterproof performance and excellent electro-optical thermal response, and has good stability in complex environments. This work proves the advantages of constructing multiple conductive interfaces inside the nanofiber film, and provides a new preparation strategy for efficient multifunctional shielding materials, which is expected to be widely used in the next generation of wearable electronic devices and wearable smart clothing.

Medical product contamination has become a threatening issue against human health, which is the main reason why protective nonwoven fabrics have gained considerable attention. In the present, there is a soaring number of studies on establishing protection systems with nonwoven composites via needle punch. Meanwhile, the disadvantages of composites, such as poor mechanical performance and texture, impose restrictions. Hence, in this study, an eco-friendly method composed of needling, hot pressing, and lamination is applied to produce water-resistant, windproof, and antimicrobial Tencel/low-melting-point polyester-thermoplastic polyurethane/Triclosan (Tencel/LMPET–TPU/TCL) laminated membranes. Field-emission scanning electron microscope (SEM) images and FTIR show needle-punched Tencel/LMPET membranes successfully coated with TPU/TCL laminated membranes, thereby extensively improving nonwoven membranes in terms of water-resistant, windproof, and antimicrobial attributes. Parameters including needle punch depth, content of LMPET fibers, and concentration of TCL are changed during the production. Specifically, Tencel/LMPET–TPU/TCL–0.1 laminated nonwovens acquire good water resistance (100 kPa), outstanding windproof performance (3/cm2/s), and good antimicrobial ability against Escherichia coli and Staphylococcus aureus. Made with a green production process that is pollution-free, the proposed products are windproof, water resistant, and antimicrobial, which ensures promising uses in the medical and protective textile fields.

We have synthesized a flexible polyurethane foam composite filled with expanded vermiculite powder and covered by concave-convex structural panel in order to improve the compression and cushioning property of PU foam. Concave-convex structural panel is that fabric cubes consisting of three layers of warp-knitted spacer fabrics arranged isometric apart between two layers of low-melting-point PET fabrics and then thermally processed at 180 °C. Effects of particle size and content of expanded vermiculite powders as well as the presence of concave-convex structural panel are examined in terms of foam structure and mechanical properties of composite PU foams. Expanded vermiculite addition decreases the energy required by pore nucleation, and the higher content of expand vermiculite results in pore diameter of foam and greater compression property. Filling of 2% vermiculites makes the compression property improved by 239% at 40% strain. Moreover, the smaller size of expanded vermiculite generates smaller and denser foam pore diameter and thus strengthened compression property. Foam composite with 800-mesh expanded vermiculites show the excellent compression property that 307% higher than neat PU foam at 40% strain. Concave-convex structural panel enhanced compression properties by 852% when fabric cubes arranged 1 cm apart and cushion efficiency by 29% compared to pure PU foam when fabric cubes arranged 4 cm apart. The resultant flexible polyurethane foam can absorb 97% energy at 12 J impact level. This composite can serve as the protective materials in kindergarten and old people's home.

Medical wound dressing with natural antibacterial efficacy is an important issue. However, few studies on Artemisia argyi oil based wound dressing have been studied because of the volatility of the Artemisia argyi oil. In this study, Artemisia argyi oil -microcapsules (AAO-MC)/PVC fibrous membrane were fabricated through emulsification-internal gelation and electrospinning method. The membranes were characterized by SEM, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and particle diameter, hydrophilicity, breathability, water vapor transmission rate (WVTR), and antibacterial performance were evaluated. The results show that AAO-MC microcapsules excellent stability, and the slow-release property. Moreover, the prepared AAO-MC/PVC fibrous membrane indicated good WVT (72.47 g/(m²·h)), high hydrophilicity (30.5°), and outstanding antibacterial rate (94.3%). This study provides a new strategy to prepare microcapsule nanofibrous membrane with excellent performance and is suggested to be a promising candidate for medical wound dressings.

In this study, we prepared a graded buffer composite by using shear thickening fluid (STF) capsules, polyurethane (PU) foam, and low-melting point PET fabric or spacer fabric with improved energy absorption performance. Various graded buffer composites are fabricated including STF capsule/PU foam covered with PET fabric (SC/PU/PET-CM) and STF capsule/PU foam covered with warp-knitted spacer fabric (SC/PU/WKSF-CM). The thermal stability and the mechanical properties of the graded buffer composite were tested. After adding STF capsules, PU foam still has good thermal stability whose weight- loss temperature reaches 200 ℃; and the compression energy and buffer performance both increases. The compression energy of S4-STF/PU is 2.26 times than that of S4-PU and 5.65 times than that of pure PU foam. Among SC/PU/PET-CM samples, HP-STF/PU graded foam composite showed the lowest impact force (3833 N). Comparatively, among SC/PU/WKSF-CM samples, the buffer performance of S4-STF/PU shows the best, and the impact value is reduced to 3921 N, which is 848 N lower (17.7%) than that of PU foam. The composites can be used as an alternative material in the field of protection.

Nowadays, various plastic products plays an important and indispensable role in our daily life. However, plastic cannot be essentially decomposed in the nature and thus led to inevitable damage to the environment. The study aims to recycle thermoplastic materials to attain the purposes of recycling, reuse, and sustainability. Polypropylene (PP) and toughening thermoplastic polyurethane (TTPU) are melt-blended for two cycles, which a small amount of compatibilizer (i.e. polypropylene grafted maleic anhydride, PP-g-MA) is added during the process. The morphology and mechanical properties of the PP/MA/TTPU blends are then measured and investigated. SEM images show that without the compatibilizer, TTPU particles demonstrate a dispersive phase in PP matrix. The presence of compatilizer improves the incompatible situation between TTPU and PP. The impact test results have proven that the incorporation of 20 wt% of TTPU and 5 wt% of compatibilizer helps to improve the interphase problem, thereby yielding the impact strength of 63.01 J/g. The tensile strength test results show that the presence of PP compensates for the insufficient rigidity and high production cost of TTPU. The flexural strength test results show that PP with high stiffness synergizes to the softness and flexural performance of TTPU. It is expected that using the secondary recovery process obtains the added value and sustainable use of plastic products, which is helpful to the sustainable development of the earth.

Metamaterials possess attractive electromagnetically left-handed properties yet their nature as an artificial structure rather than a material restricts their further applications. In this article we propose to use Co-based ferromagnetic microwires as periodical metamaterial units interweaved into a fabric to realize a “metacomposite” for steering wave propagation. By introducing ferromagnetic microwires in quartz fabric at three curvatures and periodic lengths, the electromagnetic response and microwave behaviors on both horizontally- and vertically-arranged directions were presented and investigated. Tensile behaviors of metacomposites with different ferromagnetic microwire morphologies were monitored by non-contact full field strain measurement system. At X band (8.2–12.4 GHz), metacomposites containing vertically-arranged ferromagnetic microwires show negative permittivity due to the dielectric resonance of microwire arrays. The dielectric response of metacomposites conformed to Lorentz-oscillator mode, behaving similarly to diluted plasma. When ferromagnetic microwires reached the lowest periodic curved length 2.5 mm with the highest curvature was obtained, the metacomposites presented the maximum microwave absorption of 34% and tensile stress of 273 MPa. The incorporation of ferromagnetic microwires exerts trivial influence on the mechanical properties yet homogenizes the strain and reduces the stress concentration on metacomposites. The metacomposite with a periodic curved length of 7.5 mm has less interweaving points and the highest surface float length, therefore achieving the maximum tensile strength of 458 MPa. The single negative metacomposites containing ferromagnetic microwires are featured with excellent structural properties and amenable microwave left-handed properties in controlling wave-propagating behavior, which is of practical engineering significance in structural health monitoring, sensing and stealth applications.

Water pollution, which is caused by leakage of oily substances, has been recognized as one of the most serious global environmental pollutions endangering the ecosystem. High-quality porous materials with superwettability, which are typically constructed in the form of aerogels, hold huge potential in the field of adsorption and removal of oily substances form water. Herein, we developed a facile strategy to fabricate a novel biomass absorbent with a layered tubular/sheet structure for efficient oil/water separation. The aerogels were fabricated by assembling hollow poplar catkin fiber into chitosan sheets using a directional freeze-drying method. The obtained aerogels were further wrapped with -CH3-ended siloxane structures using CH3SiCl3. This superhydrophobic aerogel (CA ≈ 154 ± 0.4°) could rapidly trap and remove oils from water with a large sorption range of 33.06–73.22 g/g. The aerogel facilitated stable oil recovery (90.07–92.34%) by squeezing after 10 sorption-desorption cycles because of its mechanical robustness (91.76% strain remaining after 50 compress-release cycles). The novel design, low cost, and sustainability of the aerogel provide an efficient and environmentally friendly solution for handling oil spills.

A significant amount of research has been conducted on applying functional materials as surgical sutures. Therefore, research on how to solve the shortcomings of surgical sutures through available materials has been given increasing attention. In this study, hydroxypropyl cellulose (HPC)/PVP/zinc acetate nanofibers were coated on absorbable collagen sutures using an electrostatic yarn winding technique. The metal disk of an electrostatic yarn spinning machine gathers nanofibers between two needles with positive and negative charges. By adjusting the positive and negative voltage, the liquid in the spinneret is stretched into fibers. The selected materials are toxicity free and have high biocompatibility. Test results indicate that the nanofiber membrane comprises evenly formed nanofibers despite the presence of zinc acetate. In addition, zinc acetate can effectively kill 99.9% of E. coli and S. aureus. Cell assay results indicate that HPC/PVP/Zn nanofiber membranes are not toxic; moreover, they improve cell adhesion, suggesting that the absorbable collagen surgical suture is profoundly wrapped in a nanofiber membrane that exerts antibacterial efficacy and reduces inflammation, thus providing a suitable environment for cell growth. The employment of electrostatic yarn wrapping technology is proven effective in providing surgical sutures with antibacterial efficacy and a more flexible range of functions.

The shear thickening fluid (STF) with unique rheology is generally combined with polyurethane (PU) skeleton to manufacture flexible sandwich composites which is widely applied in impact resistence field. In this work, experiments and numerical simulations were comparatively analyzed to investigate the non-Newtonian fluid–solid interaction (NFSI) between STF and PU skeleton during low-velocity impact. Optimization of materials selection is proposed to achieve a higher impact resistance performance. It has been found that the synchronous gradient thickening and flow of STF facilitate the load-bearing and stress diffusion performance. In contrast to Newtonian fluids, the internal STF displays both shear resistence of high-viscosity fluid and easy flow characteristic of low-viscosity fluid, creating areas of low stress in composites and improve the impact resistance performance. The fluid-optimized STF-2 sandwich composite exhibits an up to 154.7% lower peak load and 118.82% higher energy absorption. In terms of the skeleton, a lower modulus of PU foam is conductive to a stronger NFSI, which facilitates the energy exchange between STF and skeleton and further improve the impact resistance performance. As a result, the skeleton-optimized composite containing PU-1 exhibits a 20.10% lower peak load and 17.41% higher energy absorption. The NFSI mechanism and material selection optimization between non-Newtonian fluid and large deformation materials proposed in this work provide an analysis idea and design method for flexible buffering composites.

Oil spills and industrial wastewater discharge have inflicted severe damage upon the ecological environment and human health. Therefore, the development of an environmentally friendly and pollution-free membrane material for oil-water separation is imperative. This study presents the development of a novel oil-water separation material (PP-PPy-pHR) that is environmentally benign and capable of switching between wetting properties. The material was synthesised by dopamine modification, treatment with a pH-responsive polymer and the use of a high-efficiency photothermal layer composed of self-assembled polypyrrole (PPy), and it not only separates incompatible oil-water mixtures but also efficiently separates oil-water emulsions under different pH conditions. Due to the good photothermal effect of PPy, the evaporation rate of PP-PPy-pHR composite membrane loaded with PPy was 3.95 times higher than that of pure water for oily wastewater. In addition, the PPy-pHR composite membrane exhibited excellent durability and high stability in extremely acidic and alkaline solutions, showing remarkable potential for oil-water separation applications. [ABSTRACT FROM AUTHOR]

The traditional electrospinning needles are easily blocked and the processing is not suitable for mass production. In order to address the problems, this study uses a rotary linear electrode for electrospinning for the production of polyvinyl alcohol (PVA)/chitosan(CS)/graphene(Gr) nanofibrous membranes. The membranes are observed for micro-structure and tested for thermal stability, surface resistivity, and hydrophilicity, thereby examining the influence of the content of chitosan. The test results show that the presence of chitosan improves the hydrophilcity as well as affects the morphology of PVA/CS/Gr nanofibrous membranes where the nanofiber diameter is smaller. Moreover, FTIR results suggest that chitosan and PVA interact to generate hydrogen bonds that stabilize the thermal properties of nanofibrous membranes. In particular, the maximum thermal decomposition temperature of PVA/CS/Gr nanofibrous membranes composed of PVA/CS ratio being 9:1 is 297.7 ℃. Finally, using chitosan also increases the electrical conductivity and decreases the surface resistivity. This fabricated technique provides the possibility of mass-production of PVA/CS/Gr nanofibrous membranes in the future. Keywords: Rotary linear electrospinning, Nanofibrous membrane, Chitosan, Graphene, Thermal stability, Conductivity

Abstract Background Large gap healing is a difficult issue in the recovery of peripheral nerve injury. The present study provides in vivo trials of silicone rubber chambers filled with collagen containing IFN-γ or IL-4 to bridge a 15 mm sciatic nerve defect in rats. Fillings of NGF and normal saline were used as the positive and negative controls. Neuronal electrophysiology, neuronal connectivity, macrophage infiltration, location and expression levels of calcitonin gene-related peptide and histology of the regenerated nerves were evaluated. Results At the end of 6 weeks, animals from the groups of NGF and IL-4 had dramatic higher rates of successful regeneration (100 and 80%) across the wide gap as compared to the groups of IFN-γ and saline controls (30 and 40%). In addition, the NGF group had significantly higher NCV and shorter latency compared to IFN-γ group (P

In this study, impact-resistant polypropylene (MPP), thermoplastic polyurethane (TPU) and polypropylene-grafted maleic anhydride (MA) are made into MPP/TPU/MA blends using melt-compounding and injection methods. The blending morphology, crystallization behavior, and melting and thermal behaviors of the blends are evaluated in terms of the content of TPU and MA, examining the influences of the parameters. The scanning electron microscope (SEM) observation shows that 1 wt% of MA can effectively enhance the interfacial adhesion and compatibility between MPP and TPU. The differential scanning calorimetry (DSC) results show that the crystallization temperature and melting temperature of the blends are not dependent on the content of TPU or MA. However, using TPU and MA adversely affect the crystalline and melting enthalpy of the blends. The thermogravimetric analysis (TGA) and derivative thermogravimetry (DTG) curve both show that the higher the MPP, the greater the thermal stability of TPU. Likewise, using MA as compatibilizer also has a positive influence on the thermal stability of the blends. The X-ray diffraction (XRD) analyses confirm that the addition of TPU decreases the diffraction intensity of MPP, but does not harm the crystalline structure of MPP. Moreover, the addition of MA improves the compatibility between MPP and TPU. MA marginally decreases the peak value and does not influence the crystallinity degree of MPP. It is expected that the results of SEM, DSC, TGA, DTG, and XRD can serve as a valuable reference for the design of composites with improved thermal and crystallization behaviors. Keywords: Impact-resistant polypropylene, Thermoplastic polyurethane, Maleic anhydride, Thermogravimetric analysis, Derivative thermogravimetry, Blends, Crystallization

Flexible, lightweight and practical luminous fibers have aroused great interest in the field of smart textiles. In this study, we report flexible aggregation induced emission luminogen (AIEgen) fibers which can be produced in a continuous and large-scale way. Fluorescent nanofibers prepared by conjugate electrospinning are wrapped on the surface of flexible core fiber to form a skin-core AIEgen fiber. The electrospinning parameters including spinning concentration, traction rate, spinning rate and tetraphenylethylene (TPE) concentration were designed and optimized via the non-interactive orthogonal experimental design. The optimized flexible AIEgen fiber retains the excellent mechanical properties of core fiber and is equipped with the fluorescence properties of the wrapped fluorescent nanofibers. In addition, the fabricated AIEgen fibers can still exhibit good fluorescence characteristic after being stretched, bent, washed and rubbed, displaying excellent durability. Different from reported luminescent fibers which required an external power supply or complicated preparation process, the flexible AIEgen fibers fabricated in this study can be prepared continuously in a large-scale way and exhibits effectiveness in clothing display, anti-counterfeiting, information transmission and hazardous gas detection, which shows great application potential for wearable smart textiles.

The metacomposites with tailorable negative permittivity including periodic interweaving ferromagnetic mircowires were fabricated by weaving and resin transfer molding methods. By manipulating the alignment direction, periodic curved length, spacing between ferromagnetic microwires for adjusting complex permittivity and permeability, the electromagnetic wave propagation of as-prepared metacomposites under X and Ku bands were evaluated and investigated by experiment and simulation. For metacomposites composed of vertically arranged microwires, for both 1 mm and 0.5 mm spacing, the permittivity turned to negative in certain frequency bands. The simultaneous existence of short periodic curved length and spacing benefits the broadening of frequency band under which metacomposites exhibits single-negative behavior. Significant transmission windows are observed due to negative permittivity occurring at plasma frequency. The simulation results show major loss for the textile structured metacomposites under X and Ku bands derives from electric loss, and small periodic curved length tends to form uniform power loss distribution. Keywords: Fabrics/textiles, Magnetic properties, Computational modelling, Weaving

This study constructs a flexible gradient foaming structure by changes the maleic anhydride-grafted styrene-ethylene/butylene-styrene (SEBS-g-MAH) content on the basis of a two-step foaming technique. The effects of SEBS-g-MAH content and its ratio in the first and second foaming steps on microstructure, compression, quasi-static burst, dynamic cushion, and thermal performance of flexible polyurethane foam composites are investigated. Results show that, SEBS-g-MAH content affects microstructure, compressive stress, burst strength, dynamic cushion and thermal performance. Gradient foaming improves compressive stress and quasi-static bursting strength by 3.81 and 1.56 times, respectively. The absorbed energy under dynamic impact of gradient foaming can be increased by 87% relative to that in one-step foaming. This study provides a new way approach to SEBS application, and serves as a new reference for designing of energy-absorbing foam composites by filler addition. Keywords: Flexible foam, Two-step foaming, SEBS-g-MAH, Gradient structure, Dynamic cushion

People are no longer satisfied with only comfortable textile clothing with advanced technology and elevated standard of living and, thus, are gradually preferring functional textiles. In the meanwhile, the spread of medical knowledge has educated the public about the antimicrobial concept. In this study, composed of different twist coefficients and different numbers of plies, the zinc ion twisted yarns are made into knitted fabrics. Next, the knitted fabrics are examined for water vapor transmission rate and antimicrobial efficacy. The test results indicate that the water vapor transmission rate is 1013 g/m2/day for 2Zn-0C-K and 981 g/m2/day for 3Zn-0C-K. However, a rise in the twist coefficient adversely affects the water vapor transmission rate. The fabric 2Zn-3C-K exhibits the maximal air permeability of 265 cm3/cm2/s and 3Zn-3C-K 186 cm3/cm2/s. Regardless of whether it is at OD600, colony count observation, or antibacterial rate, 3Zn-5C-K exhibits the maximal antibacterial rate with the value being 0.45 at OD600 and the optimal antimicrobial efficacy being 85%. To sum up, based on the interest of the test results, production cost, and manufacturing process evaluation, 2Zn-5C-K is the optimal nonwoven fabric that achieved the maximal effects.

When impaired bones are grafted with bone scaffolds, the behaviors of osteoblast are dependent on the implant materials and surface morphology. To this end, we modulated the surface morphology of scaffolds that promote cell growth. In this study, ice-template and spraying method methods are employed to coat different proportions of PDA and PPy over the PLA/PVA weaving scaffolds, after which HA is Coated over via the electrochemical deposition, forming weaving scaffolds with electrically conductive PDA/PPy/HA coating. The test results indicate that with a PPy/PDA concentration ratio is 30, the PPy particles are more uniformly distributed on the fiber surface. The scaffolds are wrapped in a HA coating layer with a high purity, and calcium and phosphorus elements are evenly dispersed with a Ca/P ratio being 1.69. Owing to the synergistic effect between PDA and PPy coating, the scaffolds demonstrate excellent electrochemical stability and electrochemical activity. The biological activity of the scaffold increased to 274.66% under electrical stimulation. The new thinking proposed by this study extends the worth of applying textile structure to the medical field, the application of which highly increases the prospect of bone tissue engineering. [ABSTRACT FROM AUTHOR]

Particulate matter 2.5 (PM2.5) has become a public hazard to people’s lives and health. Traditional melt-blown membranes cannot filter dangerous particles due to their limited diameter, and ultra-fine electrospinning fibers are vulnerable to external forces. Therefore, creating highly efficient air filters by using an innovative technique and structure has become necessary. In this study, a combination of polypropylene (PP) melt-blown and polyvinyl alcohol (PVA)/zeolite imidazole frameworks-8 (ZIF-8) electrospinning technique is employed to construct a PP/PVA/ZIF-8 membrane with a hierarchical fibrous structure. The synergistic effect of hierarchical fibrous structure and ZIF-8 effectively captures PM2.5. The PP/PVA composite membrane loaded with 2.5% loading ZIF-8 has an average filtration efficacy reaching as high as 96.5% for PM2.5 and quality factor (Qf) of 0.099 Pa−1. The resultant membrane resists 33.34 N tensile strength and has a low pressure drop, excellent filtration efficiency, and mechanical strength. This work presents a facile preparation method that is suitable for mass production and the application of membranes to be used as air filters for highly efficient filtration of PM2.5.

With appropriate conditions, thermoplastic materials possess a good reversible ability. They are prone to exceed the reversibility range when being repeatedly processed as they cannot bear high temperatures. Therefore, this study aims to explore the impacts of the melting–recycling cycles and the presence of a compatibilizer on the omnipresent thermoplastic materials. Additionally, the tensile properties, morphology, and thermal properties are studied. The feasibility of multiple utilizations and differentiation effects are examined afterward. In this study, recycled or mechanically damaged thermoplastic polyurethane (T)/polypropylene (P) waste blends are used as the raw materials for the hot-pressing cycle, while maleic anhydride grafted polypropylene (MA) is used as the compatibilizer, thereby simulating the waste compounds. Next, the T/P/MA blends that undergo post-2nd and post-3rd recycling are evaluated for comprehensive change. The test results indicate that without MA, T/P blends exhibit significant differentiation effects due to an increase in the polypropylene content and multiple melting–recycling cycles. By contrast, the presence of MA mitigates the overall differentiation effect of T/P blends. The ultimate purpose of this study is to treat waste compounds via a simple hot-pressing approach to produce useful materials that can be used again. As a result, this study attenuates the negative influences of plastic waste on the environment while achieving sustainable development.

To characterize the interfacial microstructure and interaction at a nanoscale has a significant meaning for the interface improvement of the nanocomposites. In this study, the interfacial microstructure and features of aligned multiwalled carbon nanotube (MWNT) and conjugated polymer polyimide (PI) with three molecular structures were investigated using small-angle X-ray scattering (SAXS), wide-angle X-ray diffraction (WAXD), and fluorescence emission spectroscopy. It was found that aligned MWNT/PI nanocomposites had a nonideal two-phase system with the interfaces belonging to long period stacking ordered structure. Attributed to the π–π stacking effect, MWNT/BTDA-MPD presented the most regular arrangement verified by fractal dimension. By adopting a one-dimension correlation function, each phase dimension in aligned MWNT/PI nanocomposites was calculated and verified by high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD). The π–π stacking was demonstrated to be an important interaction between MWNT and PI via WAXD and fluorescence emission spectroscopy, and it was influenced by the linkage bond between benzene rings in PIs. This work is of significance to reveal the interfacial features between conjugated polymer and carbon nanotubes (CNTs), which is favorable for the interface design of CNT-based high performance nanocomposites.

In this study, titanium dioxide (TiO2), a mineral with a potential and supercapacitor, is used as the reinforcing material to improve the filtration efficacy of electret melt-blown fabrics. Next, the electret melt-blown fabrics are evaluated in terms of surface voltage and filtration efficiency, thereby examining the influences of the TiO2 ratio and electric field intensity. The test results indicate that the filtration efficiency is proportional to the ratio of TiO2 and electric field intensity. In particular, with a TiO2 ratio of 3 wt% and an electric field intensity of 2.5 kV/cm, the electret melt-blown fabrics demonstrate a maximal filtration efficiency of 96.32%, a lowest pressure drop of 40 Pa, and an optimal quality factor of 0.083 Pa−1.