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lectrical stimulation with conductive biomaterials shows great promising to promote skin wound healing in practical application. In this study, polypyrrole@keratin nanofiber membrane (PPy@KNM) with good conductivity was prepared using electrospinning technology and chemical in situ polymerization of pyrrole monomers. Morphological, chemical, X-ray and surface analyses suggested that PPy was deposited on the keratin nanofiber membrane (KNM). The PPy@KNM with the highest conductivity and the largest tensile strength was prepared with an oxidant concentration of 0.6 M and a dopant concentration of 0.5 M of the p-toluenesulfonic acid (p-TSA). In vitro cell culture experiments revealed that the conductive PPy@KNM performed good biocompatibility and no cytotoxicity. Electrical stimulation via the PPy@KNM can reasonably accelerate cell growth and cell proliferation with an optimal current intensity of 80 μA and a stimulation time of 5 min/d. The research outcomes demonstrated that PPy@KNM is suitable to be applied as a functional biomedical material to promote wound healing. KCI Citation Count: 0

Due to the low melt index of polylactic acid (PLA) polymer, it is difficult to melt-blown processing. Here, a new modified method to obtain a high melt index of PLA polymer and melt-blown nonwoven cloth was studied. PLA polymers are modified by the thermally degraded method of stannous octoate (Sn(Oct)2) and polyethylene glycol (PEG) to obtain a high melt index (1054 g/10 min) in comparison with a low melt index (23 g/10 min) of original unmodified PLA polymer. The fiber of modified PLA polymer melt-blown cloth is obviously thinner, having sub-micron fibers, the smallest fiber is about 200 nm. From our test, modified PLA polymer melt-blown cloth has good oil absorption, oil–water separation, and potential air filtration property. In terms of degradation, the modified PLA polymer melt-blown cloth showed excellent degradation performance in basic aqueous solutions at 55 °C at pH 12, reaching a degradation rate of around 95% at 60 h. KCI Citation Count: 0

Quality characteristics of blended yarns, which play an important role in textile quality, are continually assessed by softness, breaking strength, breaking elongation, hairiness, irregularity, etc. In this study, hemp was softened and blended with other cellulose fibers with better softness to produce yarns. The softness of hemp is obviously lower than that of the other two fibers. With the increase of hemp fiber percentage content, the yarn properties deteriorated. Therefore, the softening treatment of hemp fiber is very necessary. Moreover, the blending hemp, cotton, and viscose in the yarn structure provided synergies, improving the weak properties of ternary fibers. Results show that softening treatment and lower percentage content of the hemp fiber will result in better yarn quality, which is consistent with the derivation result of the bending theoretical model. When the percentage content of treated hemp is 40 wt%, the overall performance of blended yarn is the best. Compared with the untreated hemp-based ternary blended yarns, the hairiness of blended yarn is significantly less (3.65 ends/m, compared to 12.23 ends/m), and the irregularity of yarn is lower (27.33% and 27.70%, respectively), yarn quality improved considerably. In addition, the resulting hemp yarn showed antibacterial activity against Escherichia coli and Staphylococcus aureus. KCI Citation Count: 0

Rotating jet spinning uses the centrifugal force generated by the high-speed rotation of the motor to keep the spinning solution ejected from the nozzle to form nanofibers. At present, the research work on rotating jet spinning mainly involves the materials, properties and applications of fibers, parameter influence and jet trajectory, while there are few studies on the optimization of spinning core components. In this paper, by analyzing the force and flow state of spinning solution in the flow channel of spinning nozzle, it is found that the maximum velocity region of spinning solution will be offset. The reason for this phenomenon is that the spinning solution is subjected to Coriolis force in the rotating system, resulting in the secondary flow of solution. The relationship between nozzle parameters, solution parameters as well as process parameters, and the outlet velocity of solution was sought, and the structure of spinning nozzle was optimized. The factors affecting velocity offset in straight-tube nozzles and bent-tube nozzles are simulated. High-speed centrifugal spinning experiments were conducted using both unoptimized and optimized nozzles. KCI Citation Count: 0

Surface activation is an essential process in carbon fiber preparation for surface inertness of carbon fibers. In this study, X-ray photoelectron, Raman spectroscopies, dynamic contact angle, monofilament tensile strength and interfacial shear strength (IFSS) measurements were used to investigate the activation effects of NH4HCO3, NH4H2PO4, and NH4HSO4 electrolytes on carbon fiber surfaces under the same conductivity conditions. The results showed that the surface structures and properties of carbon fibers after treatment with different ammonium salts differed significantly. Oxidation by active oxygen [O] was stronger under acidic conditions, i.e., with NH4H2PO4 and NH4HSO4, than that under alkaline conditions, i.e., with NH4HCO3. However, when the acidity was too high, oxidation by active oxygen [O] was weakened by the effect of H+ concentration. The surface graphitization degree (R) of carbon fibers decreased slightly after treatment with the three ammonium salts because of the effects of active oxygen [O] and anionic etching or stripping. As the electrolyte acidity increased, the R decreased more significantly, and the monofilament tensile strength increased more significantly. The dynamic contact angle between the activated carbon fibers and deionized water after treatment with NH4H2PO4 was the lowest. The IFSS was the largest and was 52.3% higher than that before treatment. KCI Citation Count: 0

With the growing demand of multifunction membranes with water vapor transmission and breathable performances in many fields, design of multifunction membranes with facile fabrication is crucial and challenging. In this work, a highly breathable bi-layered polyurethanes—polyacrylonitrile/cellulose acetate (PU-PAN/CA) membrane with outstanding water vapor transmission and excellent mechanical property was fabricated by electrospinning. And then, the bi-layered PU-PAN/CA nanofibrous membranes were characterized using SEM, FTIR, tensile stress, water contact angle, air permeability, water vapor permeability and moisture management tester to evaluate the performance. The prepared PU-PAN/CA membrane has a comprehensive performance by adjusting the CA ratio of the PAN/CA layer and electrospinning time of PU layer with breathable of 21.81 mm s-1, water vapor transmission (WVT) rate of 12.18 kg m-2 day-1, and tensile strength of 8.90 MPa, which shows its certain reference significance to the prepared of multifunctional membrane. At the end, the performance of prepared membrane was compared with other membranes. The successful preparation of such interesting bi-layered membranes could provide enlighten for the preparation of other functional fibrous materials, especially in oil/water, directional water transport and moisture-wicking clothing. KCI Citation Count: 0

The development of multifunctional and high-performance fibers has received much attention owing to a broad application prospect. In this work, the synergistic effect of ionic liquid modification on dispersion of graphene and carbon nanotubes in polyamide 6(PA6) was studied, and the composite fiber was prepared using melt spinning after a simple pre-solution blending. Imidazole chloride ionic liquid is adsorbed on the surface of the two carbon nanofillers through non-covalent bond, which gives a good dispersion and interface bonding in PA6 matrix. When the mass ratio of functionalized carbon nanofillers is 1:2, the mechanical properties and thermal stability of PA6 composite fiber are significantly improved compared with the pure PA6 fiber. Moreover, the PA6 composite fiber has a UV protection factor (UPF) of 158.2 and good antistatic performance with a surface resistivity of 2.60 × 107 Ω.cm. In addition, there is an excellent photothermal conversion performance from the results of 200 W infrared light irradiation test and outdoor photothermal experiments. This work provides a new idea to prepare multifunctional and high-performance composite fibers. KCI Citation Count: 0

The formation process of beaded structure electrospun fibers in three cases: spherical collector, bowl-shaped collector, and fold-shaped collector, and the influence of electric field on jet motion and the structural evolution of fiber morphology were investigated systematically in this work. In this study, the electric field simulation was performed with the simulation software; The high-speed camera recorded the jet motion, which was characterized using parameters such as the straight jet length, envelope angle,whipping amplitude, and jet velocity. The SEM technique was employed to measure the collected fiber felt. It is found that the different collector systems will have different electric field distributions in the jet area, thus affecting its jet motion and resultant fiber morphology. Observed results showed that the electrospinning system of the spherical collector produced a stronger electric field on the collector surface, which can fully stretch the fibers and beads, producing a smaller bead structure and fewer beads. When the fold-shaped collector was adopted, its surface electric field intensity decreased, resulting in a change in the jet whip, showing a larger envelope angle and whipping amplitude, and the jet velocity decreased slightly, generating a coarser beaded fiber. The surface electric field intensity decreased again when a bowl-shaped collector was employed, the whipping area of the jet was widened, and the speed of the jet decreased again, resulting in the fiber diameter and the bead diameter increasing. The results indicate that the jet motion can be controlled by changing the collector shape to control the electric field intensity distribution, and the desired fibers with different properties are obtained.ent properties are obtained. KCI Citation Count: 0

With the increasing awareness of human environmental protection, the development of biodegradable bio-based materials has received more attention. As the off-cuts of silk, a natural protein fiber, waste silk still retains excellent properties such as biodegradability and biocompatibility, recycling and utilization of waste silk is currently very limited. To find a possible method to recycle low-cost waste silk and process it into high-value-added products, in this work, the waste silk from the silk spinning process was prepared into silk nonwoven (SN) with excellent air permeability, softness, water–oil amphiphilicity, biodegradability, and ultraviolet resistance by the wet laid process. The results showed that the uniform SN could be prepared when the alkali concentration was higher than 0.6%. The permeability of SN is higher than 80 mm/s, and the bending stiffness is lower than 0.085gf·cm2/cm. Notably, SN possesses entanglement at both fiber and fibril levels, enabling it to achieve a base strength of 0.58 MPa without additional reinforcement. The water contact angle and oil contact angle of SN were below 40° and 50°, respectively. The ultraviolet protection of SN-0.6 was classified as very good, with a degradation rate of 4.31% of SN-0.6 after 30 days of burial. The present research shows that silk nonwoven is a potential bio-based material with promising applications in the field of packaging and cleaning. KCI Citation Count: 0

Ultra-high molecular weight polyethylene (UHMWPE) acquires excellent properties while possessing poor processability. Blending low molecular weight polyethylene disentangles the molecular chain of UHMWPE and improves its processability, improving fiber productivity. In the present study, UHMWPE and its HDPE-blended fibers were produced by a high-temperature electrospinning process, and the effect of HDPE content on fiber properties was investigated in depth. Analysis of fiber surface morphology revealed the formation of uniformly distributed nano- to microscopic pores/pits, wrinkles, and grooves on the surface of blended fibers, unlike neat UHMWPE fibers containing irregular surface bulges and pits. It suggested that the blending of HDPE affected the surface topography and the thermal and mechanical properties of electrospun fibers. The tensile strength and Young’s modulus of UHMWPE fiber improved by 142 and 102% at a 67:33 mass ratio of UHMWPE and HDPE and by 84 and 132% in the case of a 50:50 composition ratio, respectively. KCI Citation Count: 0