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1.
Different silk substrates in form of spun silk tops, nonwoven web, yarn, and fabric were coated with electrically conducting doped polypyrrole (PPy) by in situ oxidative polymerization from an aqueous solution of pyrrole (Py) at room temperature using FeCl3 as catalyst. PPy-coated silk materials were characterized by optical (OM) and scanning electron (SEM) microscopy, FT-IR spectroscopy, and thermal analysis (DSC, TG). OM and SEM showed that PPy completely coated the surface of individual silk fibers and that the polymerization process occurred only at the fiber surface and not in the bulk. Dendrite-like aggregates of PPy adhered to the fiber surface, with the exception of the sample first polymerized in the form of tops and then spun into yarn using conventional industrial machines. FT-IR (ATR mode) showed a mixed spectral pattern with bands typical of silk and PPy overlapping over the entire wavenumbers range. DSC and TG showed that PPy-coated silk fibers attained a significantly higher thermal stability owing to the protective effect of the PPy layer against thermal degradation. The mechanical properties of silk fibers remained unchanged upon polymerization of Py. The different PPy-coated silk materials displayed excellent electrical properties. After exposition to atmospheric oxygen for two years a residual conductivity of 10–20 % was recorded. The conductivity decreased sharply under the conditions of domestic washing with water, while it remained essentially unchanged upon dry cleaning. Abrasion tests caused a limited increase of resistance. PPy-coated silk tops were successfully spun into yarn either pure or in blend with untreated silk fibers. The resulting yarns maintained good electrical properties.  相似文献   

2.
A simple and practical strategy has been developed for preparing polyaniline(PANi)-doped TiO2/poly(l-lactide) (P@TiP-C) fibers by a combination of coaxial-electrospinning and in-situ polymerization. The TiO2/PLLA composite fibers with TiO2 located on the surface were fabricated by coaxial-electrospinning, with PLLA as the core phase and a dispersion of TiO2 particles, a well-known photocatalyst, in the sheath phase. The aniline monomers were also located in the core phase and in-situ polymerized by ammonium persulfate (APS) after electrospinning. SEM images show that TiO2 particles were located on the surface of PLLA fibers. Photocatalytic degradation tests show that the P@TiP-C fibers exhibit enhanced photocatalytic activity for degradation of methyl orange under visible light, likely due to the synergistic effect of PANi and TiO2.  相似文献   

3.
In this paper, novel electrospun LA-PA/PET/Ag phase change composite fibers with different amount of Ag nanoparticles were prepared via the technique of electrospinning followed by UV irradiation method. The morphological structure, thermal energy storage properties, thermal energy storage and release rates of prepared LA-PA/PET/AgNO3 and LA-PA/PET/Ag composite fibers were investigated by scanning electron microscope (SEM), high-resolution transmission electron microscope (HR-TEM), differential scanning calorimeter (DSC), and the measurement of melting and freezing times, respectively. The SEM images revealed that electrospun LA-PA/PET/AgNO3 and LA-PA/PET/Ag composite fibers possessed the smooth morphologies with cylindrical shape. The corresponding average fiber diameters gradually decreased with increasing content of the AgNO3 in the solutions, and slightly smaller than those of the LA-PA/PET composite fibers with oblate morphology and wrinkled surfaces. Yellow-brown coloration of electrospun LA-PA/PET/Ag phase change composite fibers were observed after UV irradiation treatment, which demonstrated that Ag ions were successfully reduced to Ag nanoparticles. The TEM images revealed that these reduced Ag nanoparticles were homogenously dispersed within the composite fibers. The results from DSC measurements indicated that the phase change temperatures and enthalpies of electrospun LA-PA/PET/Ag phase change composite fibers with different Ag content have not be influenced by the UVirradiation treatment. The thermal energy storage and release rates of electrospun LA-PA/PET/Ag phase change composite fibers were also improved due to the combination of reduced Ag nanoparticles. These UV-irradiated electrospun phase change composite fibers with excellent thermal energy storage properties can be acted as a novel form-stable PCMs for the applications related to storage and retrieval of thermal energy.  相似文献   

4.
Graphene is classified as a carbon-based material. Structurally, graphene is made up of carbon-based two-dimensional atomic crystals and a one atom thick planar sheet of sp2-bonded carbon atoms. This sort of arrangement in graphene makes it a unique material with exceptional mechanical, physicochemical, thermal, electrical, optical, and biomedical properties. Methods for graphene-based fabric production mainly use graphene-based materials such as graphene (G), graphene oxide (GO), and reduced graphene oxide (rGO) coated on fabric or yarn. Waterborne polyurethane (WPU) is one of the most rapidly developing and active branches of polyurethane chemistry. More and more attention is being paid to graphene-coated fabrics owing to their low temperature flexibility, the presence of zero or very few VOCs (volatile organic compounds), water resistance, pH stability, superior solvent resistance, excellent weathering resistance, and desirable chemical and mechanical properties. It is used as a coating agent or adhesive for fibers, textiles, and leather. Also, graphene-containing materials have been used to enhance the properties of WPU. In this study, graphene/WPU composite solution and film was prepared to conduct basic research for developing electrical heating textiles which is not harmful to the human body, flexible and excellent in electrical properties. Graphene/WPU composite solutions were prepared with a graphene content of 0, 2, 4, 8, and 16 wt%, and graphene/WPU film was prepared with solution casting method. The graphene contents were analyzed for their surface morphology, electrical properties, and electrical heating properties.  相似文献   

5.
Ethanol, as the first coagulation bath, and several common organic solvents, as well as aqueous solutions of NH4Cl, NaHCO3 and NaOH were explored and demonstrated to be adopted as the second coagulation bath for cellulose/phosphoric acid/tetraphosphoric acid (cellulose/complex PA solvent) solution to produce novel cellulose fibers by two-stage dry-wet spinning in a laboratory scale, and effect of coagulants, cellulose concentration, solvent concentration (P2O5 concentration) and coagulation temperature on crystal structure and properties of corresponding fibers were investigated. Surface morphology of regenerated fibers as-spun from different coagulants was observed by scanning electronic microscope (SEM), indicating that methanol and 8 wt% NaOH aqueous solution all rendered cellulose fibers relatively dense and smooth surface. X-ray diffraction (XRD) analysis showed that cellulose fiber precipitated from 8 wt% NaOH aqueous solution had pronounced characteristic peak of cellulose II than those of fibers precipitated from other coagulants, and highest crystallinity and orientation. Meanwhile, those two coagulants referred above also gave cellulose fibers relatively higher tensile strength under the same prerequisite. TGA curves exhibited that fibers were thermally stable produced from two salt aqueous solutions (8 wt% NH4Cl and NaHCO3) since they had the relatively higher onset decomposition temperatures. By evaluating the effect of cellulose concentration, P2O5 concentration and coagulation temperature on the structure and properties of asprepared fibers, it was preferable to produce cellulose fiber from a solution at 20 wt% cellulose concentration, 73 % P2O5 concentration, and coagulating in methanol at coagulation temperature of 60 °C at the second-stage.  相似文献   

6.
In recent years, flexible, mechanically strong and environmental friendly thermal insulation materials have attracted considerable attention. In this work, silica aerogel/polyethylene terephthalate (PET) nonwoven fiber composite with desirable characteristics was prepared via a two-step sol-gel process followed by an ambient drying method through immersing the PET nonwoven fiber into silica sol. The silica aerogel particles were characterized by FTIR, FE-SEM, TGA and nitrogen adsorption analysis. The morphology and hydrophobic properties of neat PET nonwoven fiber and its silica aerogel composite were also investigated. For studying thermal protective properties, the thermal diffusivity was calculated from temperature distribution curves. The mean pore size of 11 nm, the surface area of 606 m2/g and the total pore volume of 1.77 cm3/g for the silica aerogel particles in the composite are obtained from nitrogen adsorption analysis, indicating the aerogel can maintain its high porosity in the nonwoven composite structure. Silica aerogel particles were efficiently covered the surface of the PET fibers and completely filled the micron size pores of the nonwoven fiber leading to a stronger hydrophobicity and higher thermal insulation performance in the aerogel composite samples compared to the neat PET nonwoven. In this regard, an almost 64 % decrease in the thermal diffusivity was achieved with 66 wt% silica aerogel.  相似文献   

7.
The regenerated cellulose fibers were prepared by wet-spinning from NaOH/thiourea/urea aqueous solvent system for the first time. The effects of coagulation and stretch conditions on the structure, morphology, and mechanical properties of the prepared fibers were investigated by wide-angle X-ray diffraction (WAXD), scanning electron microscope (SEM), and tensile tester, respectively. When the cellulose spinning dope was coagulated in 10% H2SO4/12.5% Na2SO4 aqueous solution at 15 °C, the prepared fibers had a typical crystalline structure of cellulose II and circular cross-sectional shapes with smooth surface and slightly high tensile properties to viscose fibers.  相似文献   

8.
The ability of inherently conducting polymer (ICP) coated textiles to recover gold metal from aqueous solutions containing [AuCl4]− was investigated. Nylon-lycra, nylon, acrylic, polyester and cotton were coated with a layer of polypyrrole (PPy) doped with 1,5-naphthalenedisulfonic acid (NDSA), 2-anthraquinonesulfonic acid (AQSA) orp-toluenesulfonic acid (pTS). Textiles coated with polyaniline (PAn) doped with chloride were also used. The highest gold capacity was displayed by PPy/NDSA/nylon-lycra, which exhibited a capacity of 115 mg Au/g coated textile, or 9700 mg Au/g polymer. Varying the underlying textile substrate or the ICP coating had a major effect on the gold capacity of the composites. Several ICP coated textiles recovered more than 90% of the gold initially present in solutions containing 10 ppm [AuCl4]− and 0.1 M HCl in less than 1 min. Both PPy/NDSA/nylon-lycra and PAn/Cl/nylon-lycra recovered approximately 60% of the gold and none of the iron present in a solution containing 1 ppm [AuCl4]−, 1000 ppm Fe3+ and 0.1 M HCl. The spontaneous and sustained recovery of gold metal from aqueous solutions containing [AuCl4]− using ICP coated textiles has good prospects as a potential future technology.  相似文献   

9.
Electrical conductive nanocomposite fibers were prepared with polyaniline (PANI), polyacrylonitrile (PAN) and multi-walled carbon nanotubes (MWCNTs) via electrospinning. The morphology and electrical conductivity of the PANI/PAN/MWCNTs nanocomposite fibers were characterized by scanning electron microscope (SEM) and Van De Pauw method. Electrical conductivity of nanocomposite fibers increased from 1.79 S·m?1 to 7.97 S·m?1 with increasing the MWCNTs content from 3.0 wt% to 7.0 wt%. Compared with PANI/PAN membranes, the mechanical property of PANI/PAN/MWCNTs nanocomposites fiber membranes decreased. The microwave absorption performance of composite films was analyzed using waveguide tube, which indicated that with the thickness increasing the value of RL reduced from ?4.6 to ?5.9 dB.  相似文献   

10.
The application of poly (p-phenylene-2, 6-benzobisoxazole) (PBO) fiber as reinforcement in composite material was restricted by its photo-degradation, therefore, some measures should be considered to protect PBO fiber against UV aging. In this study, A series of multilayer coating for (POSS/TiO2)n was prepared on PBO fiber surface via LbL assembly technique for enhancement of UV resistance. TiO2 as UV absorbing material was used to relieve UV-degradation of PBO. Surface elemental composition, surface morphology, mechanical and interfacial properties, and UV resistance of uncoated and coated PBO fibers were investigated. These experimental results show multilayer coating of (POSS/TiO2)n was uniform deposition on fiber surface after treatment, tensile strength decreased to certain extent, interfacial shear strength increased in a small range and UV resistance is obvious enhanced. After the same accelerated aging time under UV irradiation, the retention of tensile strength and intrinsic viscosity of coated PBO fibers were much better than that of untreated PBO fibers.  相似文献   

11.
Composite woven fabric satisfies what people require. Bamboo charcoal (BC) has been identified as a multifunctional material that has far-infrared ray, anions, deodorization and etc. BC fibers and yarns were made of bamboo charcoal powders and have further become a pervasive materials used in textile industry. In this study, cotton yarns, stainless steel/cotton (SS/C) complex yarn, bamboo charcoal/cotton (BC/C) complex yarns were woven into the plain, twill and Dobby composite woven fabrics. The warp yarn was composed of cotton yarns, and the weft yarn was made up of BC/C and SS/C complex yarns with a picking ratio of 1:1 and 3:1. Thermoplastic polyurethanes (TPU) film was then attached to the composite woven fabrics, forming the BC/SS/TPU composite woven fabrics. Tests of electromagnetic shielding effectiveness (EMSE), far-infrared emissivity, anions, water resistance, and water vapor permeability measured the single-layer, two-layer and four-layer composite woven fabrics, obtaining a far-infrared emissivity of 0.95 by 39.8 counts per minute, an anion count of 149 amount/cc, an EMSE of −11.87 dB under frequency of 900 MHz, a surface resistivity of 8×10−6 Ω/square, a water resistance of −8219 mmH2O, and water vapor permeability of 989 g/m2·h and 319 g/m2·24 h in accordance with JIS L 1099 A1 and ASTM E96 BW.  相似文献   

12.
In this study, the surface of polyester fiber was modified by means of thermal treatment with a silver carbamate complex. We used scanning electron microscopy (SEM), an X-ray diffraction technique (XRD), and X-ray photoelectron spectroscopy (XPS) to allow a detailed characterization of the silver-coated polyethylene terephthalate (PET) fibers. The results revealed remarkable changes in the surface morphology and microstructure of the silver film after thermal reduction. On SEM, the silver nanoparticles (AgNPs) were seen to be uniformly and densely deposited on the fiber surface. The XRD pattern of the silver-coated fiber indicated that the film has a crystalline structure. A continuous layer of AgNPs, between 30 and 100 nm in size, was assembled on the PET fibers. The PET/Ag composite was found to impart high conductivity to the fibers, with an electrical resistivity as low as 0.12 kΩ·cm.  相似文献   

13.
Polyaniline nanofibres are typically synthesized in a two-phase system with aniline placed in one liquid phase and the initiator in the other. The authors modified this method by introducing the monomer as a salt, thus creating a third, solid phase. This salt is in the organic phase as acetonitrile. Salts of aniline+DBSA and aniline+CSA were examined. As both these salts have limited solubility in acetonitrile, they do not dissolve during polymerization. To further reduce their solubility, acid was also added to both liquid phases. DBSA and CSA were used in the organic phase while in the aqueous phase, hydrochloric acid, sulfuric acid, DBSA and CSA were used along with the initiator (APS). Numerous polymerizations were carried out to examine various phase compositions. SEM, FTIR and UV-Vis observations revealed interesting properties of the polyaniline obtained in this way. Its morphology and spectroscopic properties strongly depend on the combination of the components used in each phase. Amorphous polyaniline was obtained as were well-developed spatial forms such as blades, spheres or nanofibres.  相似文献   

14.
For the first time, novel polyacrylonitrile (PAN)/electroconductive TiO2 (EC-TiO2) nanoparticles composite fibers have been successfully spun via wet-spinning. The composite fibers had uniform diameter and homogeneous surface. Moreover, at low content of EC-TiO2 nanoparticles, the composite fibers realized a transition from an insulator to a conductor. This work has provided a simple and effective avenue for the production of PAN/EC-TiO2 nanoparticles composite fibers that have great potential applications in the antistatic textiles.  相似文献   

15.
The inner-skinned hollow fiber composite (HFC) nanofiltration (NF) membranes were modified through the incorporation of zinc oxide nanospheres in the poly(piperazine amide) layer during the interfacial polymerization (IP) process. The active layer was coated on the inner surface of polysulfone (PSF) support membrane via Two-way coating technique. The chemical composition and morphology of HFC membrane surface were evaluated through the Attenuated Total Reflectance Fourier Transform Infrared spectroscopy (ATR-FTIR) and Scanning Electronic Microscopy (SEM). The effects of zinc oxide (ZnO) nanospheres on membrane performance including the hydrophilicity, separation performance and chlorine resistance were investigated. The results showed that the modified HFC membranes with low concentration ZnO nanospheres (1.5 wt%) had an improved flux (33.8 L·m-2·h-1) meanwhile the salt rejection of MgSO4 was well maintained (92.2 %) at 0.7 MPa. The introduction of ZnO also dramatically enhanced the chloride resistance of composite NF membranes in comparison with the control membranes prepared without ZnO. Therefore, nano metallic oxide like ZnO could be considered as a potential modifier to improve the performance of HFC nanofiltration membranes.  相似文献   

16.
Conductive aramid fiber with nickel-copper composite coating is prepared by consecutive steps of metalation swelling, sensitization, activation, nickel electroless deposition, and copper electroless deposition, respectively. The metalation swelling of aramid fiber makes the follow-up sensitization and activation feasible. The as-prepared samples are characterized by SEM, TEM, XRD and XPS. After metalation swelling, the aramid fibers look like cotton fibers with numerous nano-scale pits of 50–300 nm in diameter. Pd metal as nuclei for Ni crystal growth with the size of 10±5 nm is originated from Pd2+, which can be reduced to Pd0 by Sn2+. The Ni-Cu composite coating of 1-µm thickness has polycrystalline structure. And the electrical resistance of conductive Ni-Cu aramid fiber is 0.035 Ω/cm. The synthesis mechanism of the conductive aramid fiber with Ni-Cu composite coating is given.  相似文献   

17.
Uniform chitosan fibers (CS/PEO) with diameter of 398±76 nm were prepared by electrospinning with merely 5 wt.% of poly(ethylene oxide) (PEO) loading, and then annealed at elevated temperature without the use of additional crosslinker to improve the thermostability and solvent resistance. Swelling test shows that the CS/PEO composite fibers annealed at 200 oC were stable in 50 wt.% acetic acid aqueous solution. The mechanical strength test shows that the annealing temperature can affect the tensile strength of CS/PEO composite fiber mat. The cross-linked CS/PEO composite fibers provide a useful platform for the immobilization of palladium catalyst to catalyze the Mizoroki-Heck reactions of aromatic halides with olefins. Moreover, these CS/PEO composite fibers could be post modified with special ligands to chelate palladium species efficiently to further improve the catalytic activity and stability.  相似文献   

18.
Ployacrylonitrile (PAN) nanofibers were formed by electrospinning. Amidoxime ployacrylonitrile (AOPAN) nanofibers were prepared by reaction with hydroxylamine hydrochloride, which were used as the matrix for metal ions chelation. FTIR spectra of the PAN nanofibers and AOPAN nanofibers were recorded for analysis of the surface chemical structures. The AOPAN conventional fibers were also prepared for comparison, and surface morphologies of the modified PAN conventional fibers and PAN nanofibers were observed by FESEM. Metal ions concentrations were calculated by AAS. The chelated isothermal process and kinetics parameters of the modified PAN nanofibers and PAN conventional fibers were studied in this work. Results indicated that the saturated coordinate capacity of AOPAN nanofibers to Cu2+, Cd2+ was 3.4482 and 4.5408 mmol/g (dry fiber) respectively, nearly two times higher than that of AOPAN conventional fibers. Besides, the desorption rate of Cu2+ and Cd2+ from metal chelated AOPAN nanofibers was 87 and 92 % respectively in 1 mol/l nitric acid solution for 60 min. The isothermal processes were found to be in conformity with Langmuir model.  相似文献   

19.
This study investigated the incorporation of nanoscale germanium (Ge) and silicon dioxide (SiO2) particles into poly(vinyl alcohol) (PVA) nanofibers with the aim of developing nanostructures with far-infrared radiation effects and antimicrobial properties for biomedical applications. Composite fibers containing Ge and SiO2 were fabricated at various concentrations of Ge and/or SiO2 using electrospinning and layered on polypropylene nonwoven. The morphological properties of the nanocomposite fibers were characterized using a field-emission scanning electron microscope and a transmission electron microscope. The far-infrared emissivity and emissive power of the nanocomposite fibers were examined in the wavelength range of 5-20 μm at 37 °C. The antibacterial properties were quantitatively assessed by measuring the bacterial reductions of Staphylococcus aureus, Klebsiella pneumoniae, and Escherichia coli. Multi-component composite fibers electrospun from 11 wt% PVA solutions containing 0.5 wt% Ge and 1 wt% SiO2 nanoparticles exhibited a far-infrared emissivity of 0.891 and an emissive power of 3.44·102 W m?2 with a web area density of 5.55 g m?2. The same system exhibited a 99.9 % bacterial reduction against both Staphylococcus aureus and Escherichia coli, and showed a 34.8 % reduction of Klebsiella pneumoniae. These results demonstrate that PVA nanofibrous membranes containing Ge and SiO2 have potential in medical and healthcare applications such as wound healing dressings, skin care masks, and medical textile products.  相似文献   

20.
Thermo-responsive poly(N-isopropylacryl-amide) (PNIPAM), was grafted from cellulose paper via activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP). Six solvents with different polarities, including water, methanol, isopropanol, anisole, and methanol/H2O, isopropanol/H2O mixed solvents, were utilized to perform the grafting polymerization. The results suggested that solvent system with moderate polarity was favored to ensure successful polymerization as well as avoid the destruction of the structure of virgin paper. Modified papers with various grafting ratios were achieved by changing the reaction solvent. Compared to lump-sum addition of excess reducing agent, intermittent addition of reducing agent during the reaction process made the polymerization rate more controllable. ATRFTIR and SEM characterization indicated the successful grafting of PNIPAM from the paper surface. Water contact angle measurements revealed that the polymer-grafted papers were thermo-responsive, presenting reversible switching in wettability with the change of temperature.  相似文献   

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