Changes in Structure and Properties of Soybean Protein/Poly （vinyl alcohol） Blended Fibers Subjected to Wet Heat Treatment

The properties of soybean protein/poly（vinyl alcohol） （SP/ PVA） blended fibers subjected to wet heat treatment in hot water were measured. The structure of fibers was investigated by scanning electron microscope （SEM）, Fourier transform infrared （FTIR） spectroscopy, wide-angle X-ray diffraction （WXD） and differential scanning calorimetry （DSC）. The results show that the wet heat treatment above 100℃ has a great influence on the properties and structure of SP/PVA blended fibers. After the wet heat treatment at high temperature, the fibers exhibit the severe shrinking and yellowing, the great decrease in breaking strength and adhesive aggregation. The fibers show a broader main X-ray diffraction peak with the disappearance of minor diffraction peaks, a double DSC melting behavior with the peak temperatures of 215 and 233℃, and a weaker intensity of crystallization-sensitive absorbance peak of PVA component at 1 142 cm^-1. Therefore it is concluded that the wet heat treatment above 100℃ leads to a change in the crystalline structure of fibers and the scission and degradation of PVA macromolecular chains.     

Preparation of A-type zeolite membranes on nonporous metal supports by using electrophoretic technique

A-type zeolite membranes were prepared on the nonporous metal supports by using electrophoretic technique. The as-synthesized membranes were characterized by XRD and SEM. The effect of the applied potential on the formation of the A-type zeolite membrane was investigated,and the formation mechanism of zeolite membrane in the electric field was discussed. The results showed that the negative charged zeolite particles could migrate to the anode metal surface homogenously and rapidly under the action of the applied electric field, consequently formed uniform and dense membranes in short time. The applied potential bad great effect on the membrane formation, and more uniform and denser zeolite membranes were prepared on the nonporous metal supports with 1 V potential.     

Melt-Spinning of Nano-Hydroxyapatite/Poly(ε-caprolactone) Composite Fibers for Potential Application in Bone Tissue Engineering

Nano-hydroxyapatite/poly( ε-caprolactone)( n HA/PCL)composite materials are among the best candidates for application in bone tissue engineering. As the main technique to fabricate porous scaffolds, electrospinning produce scaffolds with unsatisfactory mechanical strength and limited pore size for cell infiltration.Micron-sized fiber assembly with higher mechanical strength is qualified to structure hybrid scaffolds. In this study, n HA/PCL monofilament fibers with different mass ratios were fabricated through melt-spinning. Transmission electron microscope( TEM)was used to observe the aggregation between n HA particles. Other characterizations including scanning electron microscopy( SEM),attenuated total reflection Fourier transform infrared spectroscopy( ATR-FTIR) and X-ray diffraction( XRD) were done to discuss the morphology, components and crystallization of the n HA/PCL composite fibers, respectively. The influence of n HA/PCL mass ratio on the tensile properties and water contact angle of composite fibers was also studied. The SEM images show the homogeneous dispersion of nano particles in the polymer matrix. Besides,n HA content increases the tensile strength, initial modulus and hydrophilicity of the composite fibers under the premise of spinnability. This kind of fibers is strong enough to fabricate fiber assembly which may have potential application in bone tissue engineering.     

Synthesis and Electrochemical Properties of Porous α-Co(OH)_2 and Co_3O_4 Microspheres

Both α-Co(OH)_2 and Co_3O_4 porous microspheres have been synthesized by the simple solvothermal process as well as subsequent treatment. The morphologies and structures of the as-synthesized products were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM), transmission electron microscopy(TEM), and X-ray photoelectron spectroscopy(XPS). Both samples have spherical structures consisting of nanosheets, with similar crystallinity. The electrochemical properties of both samples were further investigated. Both samples show excellent electrochemical performances including high specific capacity, good cycling stability and rate capability. All results show that these microspheres exhibit potential applications in energy storage field.     

Fabrication and Drug Release Property of Silk Fibroin-Based Weft-Knitted Stents

This paper was to develop a weft-knitted stent coated by a drug-loaded electro-spun fibrous membrane and then investigate its morphology, mechanical properties and in vitro drug release property. This work was started by weft-knitting of an inner layer of such stent using polydioxanone( PDO) and silkfilament.Subsequently,5-fluorouracil( 5-FU) and curcumin( CUR) ioaded silk fibroin( SF) membranes were coated on the surface of the weftknitted stent using electro-spinning technique to endow the drug delivery function of the stent. The results show that the radial compression strength and circumferential expanding strength can reach above( 9. 1 ± 0. 4) cN/cm~2 and( 205. 0 ± 0. 2) c N/mm,respectively. The drug releasing behaviors can be sustained for 400 h. It is concluded that the stents have potential application as anintestinal stent in the future.     

Collagen/Chitosan Electrospun Nanofibrous Membrane for Wound Dressing

Collagen(Col)/chitosan(CS)nanofibrous membrane has great potential to be used as wound dressing.However,current Col/CS nanofibrous membrane produced from electrospinning can not offer sufficient mechanical strength for practical applications.Herein,a novel mixed solvent was used to prepare next-generation high-strength Col/CS nanofibrous membrane.Meanwhile,the optimal Col to CS weight ratio was investigated as well.The asproduced membrane was examined by scanning electron microscopy(SEM),attenuated total reflectance Fourier transform infrared spectroscopy(ATR-FTIR),differential scanning calorimetry(DSC),and XF-1A tester to study its morphological,chemical,thermal and mechanical properties.The preliminary results demonstrated that the mechanical properties of Col/CS nanofibrous membranes were enhanced substantially with the increase of CS weight ratios from 0 to 90%and the optimal Col to CS weight ratio was determined to be 1∶1.A promising way was presented to fabricate Col/CS electrospun nanofibrous membrane with sufficient mechanical strength for practical wound dressing applications.     

A study on poly (N-vinyl-2-pyrrolidone) covalently bonded NiTi surface for inhibiting protein adsorption

Near equiatomic NiTi alloys have been extensively applied as biomaterials owing to its unique shape memory effect, superelasticity and biocompatibility. It has been demonstrated that surfaces capable of preventing plasma protein adsorption could reduce the reactivity of biomaterials with human blood. This motivated a lot of researches on the surface modification of NiTi alloy. In the present work, following heat and alkaline treatment and silanization by trichlorovinylsilane (TCVS), coating of poly (N-vinyl-2-pyrrolidone) (PVP) was produced on the NiTi alloy by gamma ray induced chemical bonding. The structures and properties of modified NiTi were characterized and in vitro biocompatibility of plasma protein adsorption was investigated. The results indicated that heat treatment at 823 K for 1 h could result in the formation of a protective TiO2 layer with “Ni-free” zone on NiTi surface. It was found that PVP was covalently bonded on NiTi surface to create a hydrophilic layer for inhibiting protein adsorption on the surface. The present work offers a green approach to introduce a bioorganic surface on metal and other polymeric or inorganic substrates by gamma irradiation.     

Cationic Organic/Inorganic Hybrids and Their Swelling Properties

Specific properties of poly（dimethylsiloxanes）, such as low glass transition temperature, low surface energy, good insulating properties, biological and chemical inertness, high diffusion coefficient of gases, make them very attractive for practical applications in the daily life. However, there is a great interest last time in the preparation of ionic organic/inorganic materials with new properties for new applications. Quaternary ammonium salt（QAS） groups included in siloxane copolymers could induce new interesting properties such as： permanent fungicidal and bactericidal properties, which make them very attractive as materials for sanitary applications, improved selectivity coefficients of the gas-separation membranes, ion-exchange properties and so forth. So far, QAS groups have been located in the side chain.     

Functionalization of PCL fibrous membrane with RGD peptide by a naturally occurring condensation reaction

Poly(e-caprolactone)(PCL)is widely adopted as an ingredient for tissue engineering scaffolds.To improve its cell affinity,in this study,we developed a new method to introduce bioactive RGD peptides onto the surface of PCL via condensation reaction between 2-cyanobenzothiazole(CBT)and D-cysteine.The PCL fibrous membranes were prepared by electrospinning,and RGD functionalization was characterized by fluorescence microscopy,scanning electron microscopy(SEM),X-ray photoelectron spectroscopy(XPS)and water contact angle(WCA).As expected,our results demonstrated the successful RGD immobilization on the surface of PCL.RGD modification improved the hydrophilicity of PCL,changing their WCA from 112.20°to38.35°.Cell adhesion,spreading and proliferation of 3T3fibroblasts were also enhanced.We therefore believe that the methods reported in this study was facile and effective for functional modification of the hydrophobic PCL scaffolds.The moderate reaction conditions are also suitable for covalent immobilization of bioactive molecules onto PCL.     

Fabrication and character ization of electrospun TiO2/CuS micro–nano-scaled composite fibers

A process to fabricate a kind of novel micro–nano scaled TiO2/CuS composite fibers by electrospinning technique and chemical precipitation method was developed in the present study. The microstructures and photoelectronic properties of the fibers were characterize d using SEM, FT-IR, UV–vis and fluorescence spectroscopy. The results revealed that the TiO2 portion in the composite fibers was a mixture rutile and anatase phases while TiO2 and CuS had been fully composite. The fibers had smooth surface with a diameter of 50–300 nm. Comparing with pure TiO2 fiber, the TiO2/CuS micro–nano-scaled composite fibers exhibited a strong absorption in the visible light region and the efficiency of photo-induced charge separation were enhanced. This composite system is of widely potential applications in the areas such as solar cells, supercapacity, photocatalysis, etc.     

Structure and Properties of Degradable Polybutylene Succinate Fibers

Polybutylene succinate(PBS) fiber is a kind of synthetic fibers with excellent properties and biodegradability, which has been produced on a large scale in China. To investigate the application properties of PBS fibers, the structure and properties were systematically studied in this paper. The microstructures and thermal properties of PBS fibers were analyzed by Fourier transform infrared(FTIR) spectroscopy, X-ray diffraction(XRD), scanning electron microscopy(SEM), thermo gravimetric(TG) and differential scanning calorimetry(DSC). The mechanical properties, chemical stability and dyeing properties of PBS fibers were also studied. The results show that PBS fibers are α-crystalline with a crystallinity of 58.56%. PBS fibers have an excellent thermal stability and the initial temperature of thermal degradation is 370 ℃. The tensile strength, the elongation at break, the elastic recovery rate at a fixed elongation(5%) and the moisture regain rate of PBS fibers are 29.57 cN/tex, 90.94%, 44.55% and 5.04%, respectively. The chemical stability is as follows: alkali resistanceacid resistanceoxidation resistance. PBS fibers have an excellent dye uptake by carrier dyeing of disperse dyes.     

Influence of Dispersion of Nano-Zn0 Particles in Polymer Matrices on Properties of Relevant Nano Composite Fibers

The surface-passivated and non-surface-passivated zinc oxide nano-particles （marked as s-nanoZnO and ns-nanoZnO respectively） were evenly dispersed in polymer solutions with the aid of ultrasonic vibration to prepare nanocomposite film by free casting and to prepare nanocomposite fibers by wet spinning and to prepare nancomposites coating by surface smearing. The dispersion of s-nanoZnO and nsnanoZnO in PAN matrix were observed by transmittance electron microscopy, the mechanical properties of the relevant compesite samples were studied by INSRTON tensile strength tester. It was found that s-nanoZnO behaves a well-dispersed morphology in PAN films and fibers when its concentration was 2 wt% but ns-nanoZnO nano particles agglomerate into larger congeries in PAN films. It means that the surface-passivated process oft zinc oxide nano. particles was effective to disperse. The relative intensity and elonsation at break of s-nanoZnO-PAN composite fibers show maximum values with the increase of nano particle content in compesites （from 0 wt% to 2 wt% of s- nanoZnO）. The elasticity of the composite fibers increases whereas their modulus declines. Balanced the changes of the properties mentioned above, 2 wt% s-nanoZnO in PAN matrix is a proper content for the composite fibers spun by wet spinning. The result of surface smearing test means that the reactim between s-nanoZnO and polymer can be indicated by the color of nanocomposite surface coat on fibers.     

Fabrication and properties of aluminum silicate fibrous materials with in situsynthesized K_2Ti_6O_(13) whiskers

To improve their mechanical and thermal insulation properties, aluminum silicate fibrous materials with in situ synthesized K_2Ti_6O_(13) whiskers were prepared by firing a mixture of short aluminum silicate fibers and gel powders obtained from a sol–gel process. During the preparation process, the fiber surface was coated with K_2Ti_6O_(13) whiskers after the fibers were subjected to a heat treatment carried out at various temperatures. The effects of process parameters on the microstructure, compressive strength, and thermal conductivity were analyzed systematically. The results show that higher treatment temperatures and longer treatment durations promoted the development of K_2Ti_6O_(13) whiskers on the surface of aluminum silicate fibers; in addition, the intersection structure between whiskers modulated the morphology and volume of the multi-aperture structure among fibers, substantially increasing the fibers' compressive strength and reducing their heat conduction and convective heat transfer at high temperatures.     

Coating for Nano Super Soil-repellency of Cashmere Fabric

The nano-size metal oxide was prepared by the single-disperse technique on liquid phase, and formed sol dusters, its uniform film was covered on the surface of cashmere fibers by coating, and it had good oil repellency and water repellency. The results of IR（infrared） Spectrometer analysis revealed： The nano material combines through the strong bonds with the surface of cashmere fibers by the live groups. These analyses by SEM techniques showed that the nano material was distributed on the fiber surface even, and the nano material formed the strong peak of the regular crystal phase structure using the X-Ray Diffractometry （XRD） to analysis the fabric. The optimum techniques were selected by a series of experiments, coated cashmere fabric not only has preserved original properties of softness and comfort, but also has good properties of Bi-repellency function. Therefore, the technique will have potential appfication in engineers.     

Formation of drug-loaded electrospun twin fibers

Electrospinning is a well-known process for producing submicrometer fibers, which have wide applications in many fields, especially in tissue engineering scaffolds and drug-delivery systems. This paper presents the formation of drug-loaded electrospun twin fibers. The correlations between the twin fiber formation and the polymer materials or the loaded drugs were studied by using poly(l-lactide) and poly(l-lactide-co-glycolide) as electrospinning materials, and rifampin and paclitaxel as loaded drugs. Scanning electron microscopy showed that the formation of twin fibers is significantly affected by the loaded drug but not the polymer material. A possible reason for twin fiber formation was analyzed.     

The Surface Properties and Tensile Strength of HSPE Fiber Treated by Controlling Oxidation in Chromic Acid

This work reported on the surface modification of high strength polyethylene(HSPE)fiber by chemical etching in chromic acid.The surface chemistry,the functional group contents, the wetting ability, the surface morphology and the tensile strength of modified fibers were investigated. The results show that, the surface roughness,surface wet properties and active functional group can be introduced on the HSPE fiber surface by this method,which will improve the interface adhesion in the composites, and the decrease of the tensile strength of modified fibers can be controlled.     

Effect of chemical vapor infiltration treatment on the wave-absorbing performance of carbon fiber/cement composites

Short carbon fibers were treated at high temperatures around 1100℃ through chemical vapor infiltration technology. A thinner layer ofpyrocarbon was deposited on the fiber surface. The dispersion of carbon fibers in a cement matrix and the mechanical properties of carbon fiber/cement composites were investigated by scanning electron microscopy (SEM) and other tests. The reflec- tivity of electromagnetic waves by the composites was measured in the frequency range of 8.0-18 GHz for different carbon fiber contents of 0.2wt%, 0.4wt%, 0.6wt%, and 1.0wt%. The results show that the reflectivity tends to increase with the increase of fiber content above 0.4wt%. The minimum reflectivity is -19.3 dB and the composites exhibit wave-absorbing performances. After pyrocarbon is deposited on the fiber, all the refiectivity data are far greater. They are all above -10 dB and display mainly wave-reflecting performances.     

Preparation and cytocompatibility of polylactic acid/hydroxyapatite/graphene oxide nanocomposite fibrous membrane

A series of polylactic acid (PLA) based nanocomposite fibrous membranes,including neat PLA,PLA/hydroxyapatite (HA) and PLA/HA/graphene oxide (GO),were fabricated via electrospinning method.The morphology and composition were investigated by scanning electron microscopy (SEM),X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) respectively.The thermal stability was determined by thermogravimetric analysis (TGA).To estimate the cytocompatibility of asprepared PLA/HA/GO fibrous membrane,MC3T3-E1 cells were cultured,and the corresponding cell adhesion and differentiation capability were investigated by fluorescence microscopy,SEM and MTT test.The electrospun ternary PLA/HA/GO membrane exhibited three-dimensional fibrous structure with relatively rough surface morphology,which made itself ideal for cell attachment and proliferation in bone tissue regeneration.The fluorescence microscopy,SEM and MTT test confirmed that the PLA/HA/GO nanocomposite fibrous membrane created a proper environment for the seeding and proliferation of MC3T3-E1 cells.     

Graphite-polypyrrole coated 316L stainless steel as bipolar plates for proton exchange membrane fuel cells

316L stainless steel (SS 316L) is quite attractive as bipolar plates in proton exchange membrane fuel cells (PEMFC). In this study, graphite-polypyrrole was coated on SS 316L by the method of cyclic voltammetry. The surface morphology and chemical composition of the graphite-polypyrrole composite coating were investigated by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). A simulated working environment of PEMFC was applied for testing the corrosion properties of graphite-polypyrrole coated SS 316L. The current densities in the simulated PEMFC anode and cathode conditions are around 3×10-9 and 9×10-5 A·cm-2, respectively. In addition, the interfacial contact resistance (ICR) was also investigated. The ICR value of graphite-polypyrrole coated SS 316L is much lower than that of bare SS 316L. Therefore, graphite-polypyrrole coated SS 316L indicates a great potential for the application in PEMFC.     

Fabrication and properties of aluminum silicate fibrous materials with <Emphasis Type="Italic">in situ</Emphasis> synthesized K<Subscript>2</Subscript>Ti<Subscript>6</Subscript>O<Subscript>13</Subscript> whiskers

To improve their mechanical and thermal insulation properties, aluminum silicate fibrous materials with in situ synthesized K₂Ti₆O₁₃ whiskers were prepared by firing a mixture of short aluminum silicate fibers and gel powders obtained from a sol-gel process. During the preparation process, the fiber surface was coated with K₂Ti₆O₁₃ whiskers after the fibers were subjected to a heat treatment carried out at various temperatures. The effects of process parameters on the microstructure, compressive strength, and thermal conductivity were analyzed systematically. The results show that higher treatment temperatures and longer treatment durations promoted the development of K₂Ti₆O₁₃ whiskers on the surface of aluminum silicate fibers; in addition, the intersection structure between whiskers modulated the morphology and volume of the multi-aperture structure among fibers, substantially increasing the fibers' compressive strength and reducing their heat conduction and convective heat transfer at high temperatures.