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1.
Water-dispersible hydrolyzed Kevlar nanofibers (hANFs) prepared by acid-assisted hydrothermal treatments of Kevlar nanofibers (ANFs) were first incorporated into carboxylated acrylonitrile butadiene rubber (XNBR) by a latex co-coagulation method. The obtained hANFs maintained the one-dimensional nanofibrous morphology and crystal structure as ANFs. There were amounts of polar groups appearing at the end of hANFs molecular chains after hydrothermal process, which led to the strong hydrogen bonding interaction between the filler and XNBR matrix. The results indicated that hANFs had significant reinforcement effects on the mechanical properties, crosslink density, and thermal stability of XNBR matrix. In comparison with those of neat XNBR, the tensile strength, tear strength, crosslink density, and maximum heat decomposition temperature (Tmax) of XNBR/hANFs nanocomposites filled with 7 phr hANFs increased by 236%, 161%, 35%, and 19.64 °C, respectively. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47698.  相似文献   

2.
Two ferrocenyl‐substituted N‐acetyl‐2‐pyrazolines, N‐acetyl‐3‐(2‐furyl)‐5‐ferrocenyl‐2‐pyrazoline (Fc‐1) and N‐acetyl‐3‐(2‐thienyl)‐5‐ferrocenyl‐2‐pyrazoline (Fc‐2) electrospun fibers, were produced in the presence of plasma‐modified chitosan (PMCh)/poly(ethylene terephthalate) (PET) supporting polymers with an electrospinning method. The morphological and chemical characterizations of the PMCh/PET/Fc‐1 and PMCh/PET/Fc‐2 electrospun fibers were determined by scanning electron microscopy coupled with energy‐dispersive X‐ray spectroscopy analysis. Thermogravimetric analysis results indicated the presence of ferrocene within the PMCh/PET nanofibers. The electrochemical behavior of the PMCh/PET/Fc‐1 and PMCh/PET/Fc‐2 electrospun fibers were investigated by cyclic voltammetry measurements based on the ferrocene/ferrocenium redox couple. The new PMCh/PET/Fc‐1 and PMCh/PET/Fc‐2 electrospun fibers aggregated on the indium tin oxide were used for phosphate anion sensing. The highest oxidation peak currents were observed for the PMCh/PET/Fc‐1 electrospun fibers at about 0.56 V in 0.1M phosphate buffer. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43344.  相似文献   

3.
There has been growing interest in fiber modification for several industrial applications. The modifications have mostly been done to improve the fiber properties. However, the information regarding fiber modification via click chemistry is still limited. In this work, two strategies of click chemistry are evaluated for modifying commercial paper without the addition of copper catalyst. The first strategy is the direct reaction between azidated fiber and propargylated fiber, and the second strategy is to bridge azidated fiber with a self‐made alkyne terminal crosslinker. Native and chemically modified fibers were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and 1H‐NMR spectroscopy. The effects of the two clicking strategies on the fiber were further investigated by making handsheets. In terms of mechanical properties, the bridge‐clicking strategy was found to produce better handsheets than the direct‐clicking strategy. These modified fibers would be an interesting application for the packaging and printing industries. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43576.  相似文献   

4.
Polyacrylonitrile nanofibers (PANnf's) were electrospun directly onto an indium tin oxide (ITO)‐coated glass substrate. The PANnf/ITO electrode was partially hydrolyzed with an NaOH aqueous solution at ambient temperature to convert the nitrile groups of the PANnf's into carboxyl groups was confirmed by Fourier transform infrared spectroscopy. Furthermore, 1‐ethyl‐3‐(3‐dimethylaminopropyl) carbodiimide–N‐hydroxy succinimide chemistry was used to activate the ? COOH groups of PANnf's for the covalent co‐immobilization of monoclonal antibodies against Vibrio cholerae and bovine serum albumin for V. cholerae toxin detection. Structural, functional, and electrochemical studies of the PANnf/ITO electrode and BSA/Ab/PANnf/ITO immunoelectrode were performed, and found a uniform distribution of nanofibers with diameter of 325 ± 7.7% nm. The electrochemical response studies showed an improved sensing performance of the immunoelectrode with a detection of 6.25–500 ng/mL, a low limit of detection of 0.22 ng/mL, a sensitivity of 90 nA ng?1 mL cm?2, an association constant of 45.2 ng/mL, and a dissociation constant of 8 ng/mL. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44170.  相似文献   

5.
The effects of alignment of polyacrylonitrile (PAN) nanofibers and a two‐step drawing process on the mechanical properties of the fibers were evaluated in the current study. The alignment was achieved using a high‐speed collector in electrospinning synthesis of the nanofibers. Under optimal two‐step drawing conditions (e.g., hot‐water and hot‐air stretching), the PAN nanofiber felts exhibited large improvements in both alignment and molecular chain‐orientation. Large increase in crystallinity, crystallite size, and molecular chain orientation were observed with increasing draw ratio. Optimally, stretched PAN‐based nanofibers exhibited 5.3 times higher tensile strength and 6.7 times higher tensile modulus than those of the pristine one. In addition, bulk density of the drawn PAN nanofibers increased from 0.19 to 0.33 g/cm3. Our results show that fully extended and oriented polymer chains are critical in achieving the highest mechanical properties of the electrospun PAN nanofibers. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43945.  相似文献   

6.
Electrospinning from a capillary is one of the methods for the production of nanofibers. The specific properties of such fibers result first of all from their large specific surface and the high porosity of the fiber mat. This article presents a process for producing functional nanofibers with antimicrobiological properties by electrospinning from polyacrylonitrile/dimethyl sulphoxide solution containing a bioactive agent based on quaternary ammonium salts (N, N, n, n,‐didecyl‐N,N‐dimethylammonium chloride, Bis‐(3‐aminopropyl)‐dodecylamine) and 2‐propanol. The structure of the nanofibers obtained and their antimicrobial activity are investigated. A 5 wt % addition of bioactive preparation to the polymer solution (concentration of active substance in solution about 1.5 wt %) makes it possible to obtain fibers showing good bactericidal properties. After 6 h in contact with these fibers, Escherichia coli are eliminated to a level of 99.84% and Staphylococcus aureus to 99.99%. The IR spectrophotometric measurements do not indicate a residue of solvent in the bioactive nanofibers and show an increase in content of CH and CH2 groups in relation to the pure nanofibers, which is connected with the presence of the biocide. Their degree of crystallinity determined by the X‐ray scattering method is 44.4%. The nanofibers obtained can be designed for medical and filtration applications. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013  相似文献   

7.
This article reports a new needleless emulsion electrospinning method for scale‐up fabrication of ultrathin core–shell polyacrylonitrile (PAN)/isophorone diisocyanate (IPDI) fibers. These core–shell fibers can be incorporated at the interfaces of polymer composites for interfacial toughening and self‐repairing due to polymerization of IPDI triggered by environmental moisture. The electrospinnable PAN/IPDI emulsion was prepared by blending PAN/N,N‐dimethylformamide and IPDI/N,N‐dimethylformamide solutions (with the solute mass fraction of 1 : 1). The electrospinning setup consisted of a pair of aligned metal wires as spinneret (positive electrode) to infuse the PAN/IPDI emulsion and a rotary metal disk as fiber collector (negative electrode). The formed ultrathin core–shell PAN/IPDI fibers were collected with the diameter in the range from 300 nm to 3 μm depending on the solution concentration and process parameters. Optical microscopy, scanning electron microscopy, and Fourier transform infrared spectroscopy were used to characterize the core–shell nanostructures. Dependencies of the fiber diameter on the PAN/IPDI concentration, wire spacing, and wire diameter were examined. Results show that needleless emulsion electrospinning provides a feasible low‐cost manufacturing technique for scalable, continuous fabrication of core–shell nanofibers for potential applications in self‐repairing composites, drug delivery, etc. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40896.  相似文献   

8.
In this study, we present a new approach to modify the surface of Kevlar‐29 fiber by the complexation. The surface of Kevlar‐29 fiber was treated by calcium chloride (CaCl2) ethanol solution. The structure and morphology of the modified Kevlar‐29 fiber were characterized by Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy, X‐ray diffraction instrument, atomic force microscopy, and scanning electron microscopy. The results showed that CaCl2 treatment's method can cause changes of the chemical groups of Kevlar‐29 fiber. The amino‐groups of Kevlar‐29 fiber were freed and the contents of ‐C‐N‐ increased. The changes can improve the surface roughness of Kevlar‐29 fibers. This can increase the adhesive of Kevlar fiber/epoxy composites. From the ILSS and mechanical properties values, it can be concluded that treatment with 5 wt % CaCl2 for 5 h is the optimum complexation condition. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41358.  相似文献   

9.
In this study, three different acrylonitrile (AN)‐based polymers, including polyacrylonitrile (PAN), poly(acrylonitrile‐co‐vinyl acetate) [P(AN‐co‐VAc)], and poly(acrylonitrile‐co‐itaconic acid) [P(AN‐co‐IA)], were used as precursors to synthesize activated carbon nanofibers (ACNFs). An electrospinning method was used to produce nanofibers. Oxidative stabilization, carbonization, and finally, activation through a specific heating regimen were applied to the electrospun fibers to produce ACNFs. Stabilization, carbonization, and activation were carried out at 230, 600, and 750 °C, respectively. Scanning electron microscopy, thermogravimetric analysis (TGA), and porosimetry were used to characterize the fibers in each step. According to the fiber diameter variation measurements, the pore extension procedure overcame the shrinkage of the fibers with copolymer precursors. However, the shrinkage process dominated the scene for the PAN homopolymer, and this led to an increase in the fiber diameter. The 328 m2/g Brunauer–Emmett–Teller surface area for ACNFs with PAN precursor were augmented to 614 and 564 m2/g for P(AN‐co‐VAc) and P(AN‐co‐IA), respectively. The TGA results show that the P(AN‐co‐IA)‐based ACNFs exhibited a higher thermal durability in comparison to the fibers of PAN and P(AN‐co‐VAc). The application of these copolymers instead of AN homopolymer enhanced the thermal stability and increased the surface area of the ACNFs even in low‐temperature carbonization and activation processes. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44381.  相似文献   

10.
Poly(vinyl alcohol) (PVA) nanofibers containing halloysite nanotubes (HNTs) loaded with sodium d ‐pantothenate (SDP) were successfully fabricated via simple blend‐electrospinning. SDP was efficiently loaded into the innate HNT lumen with an SDP/HNT mass ratio of 1.5:1 via vacuum treatment. The SDP‐loaded HNT‐inclusion complex was evaluated with drug‐loading efficiency testing, Fourier transform infrared (FTIR) spectroscopy, and X‐ray diffraction. The morphologies of the nanofibers were observed by scanning electron microscopy, which revealed uniform and smooth surfaces of the nanofibers. The addition of HNTs to the composite nanofibers increased the viscosity of the polymer solution, and this suggested shorter fiber diameters. FTIR spectroscopy verified the good compatibility of the SDP and HNTs with PVA. Moreover, the swelling properties were found to quantitatively correlate with weight loss. In vitro drug‐release testing revealed that the HNTs and crosslinking reaction most dramatically affected the sustained release of SDP from the PVA and SDP‐loaded HNT complex. In the drug‐release kinetics model, SDP release depended on the diffusion caused by the deformation of the polymer‐based structures in the medium; it followed Fickian diffusion with acceptable coefficient of determination (r2) values between 0.88 and 0.94. Most importantly, the HNTs as natural biocontainers effectively modulated the release profile by loading the active compound in harmony with the electrospun nanofibers. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42900.  相似文献   

11.
Electrospun nanocomposites of poly(ε‐caprolactone) (PCL) incorporated with PCL‐grafted cellulose nanocrystals (PCL‐g‐CNC) were produced. PCL chains were grafted from cellulose nanocrystals (CNC) surface by ring‐opening polymerization. Grafting was confirmed by infrared spectroscopy (FTIR) and thermogravimetric analyses (TGA). The resulting PCL‐g‐CNC were then incorporated into a PCL matrix at various loadings. Homogeneous nanofibers with average diameter decreasing with the addition of PCL‐g‐CNC were observed by scanning electron microscopy (SEM). PCL‐g‐CNC domains incorporated into the PCL matrix were visualized by transmission electron microscopy (TEM). Thermal and mechanical properties of the mats were analyzed by differential scanning calorimetry (DSC), TGA and dynamic mechanical analysis (DMA). The addition of PCL‐g‐CNC into the PCL matrix caused changes in the thermal behavior and crystallinity of the electrospun fibers. Significant improvements in Young's modulus and in strain at break with increasing PCL‐g‐CNC loadings were found. These results highlighted the great potential of cellulose nanocrystals as a reinforcement phase in electrospun PCL mats, which can be used as biomedical materials. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43445.  相似文献   

12.
Poly(lactic acid) (PLA) nanofibers, as a biodegradable and environmentally friendly material, have potential applications such as biological medicine, efficient filter material, and so on. PLA nanofibers are usually prepared by solution electrospinning method with toxic solvents, such as chloroform, chloromethane, and N,N‐dimethyl formamide. In this work, PLA nanofibers were fabricated with a self‐designed melt differential electrospinning device, assisted by addition of nontoxic acetyl tributyl citrate (ATBC) and by airflow. Molecular dynamics simulations were performed to understand the experimental results. The results revealed that the fiber diameter decreased with increasing airflow velocity, and fibers with a diameter as small as 236 nm were obtained at the highest airflow velocity of 25 m/s (with 6 wt % of ATBC). Furthermore, a significantly accelerated falling speed of the jets of about 347 times of that without airflow was achieved at a flow rate of 25 m/s. These results demonstrated that the combination of adding ATBC and airflow assistance was a good strategy to achieve finer fibers with improved stability and efficiency, making it a promising way for mass green production of PLA nanofibers. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46554.  相似文献   

13.
Ultrafiltration (UF) is a size selective pressure‐driven membrane separation process increasingly required for high efficient water treatment and suspended solids removal in many industrial applications. This study examined the morphology of as‐prepared cellulose nanofibers and then utilized the nanofibers dispersion to fabricate nanofibrous nanoporous membranes with potential wide applications in various fields including water treatment. The nanofibers were prepared using a simple and powerful mechanical high intensity ultrasonication following a pre‐chemical treatment of α‐cellulose. The cellulose nanofibers’ morphology, crystallinity, and yield were found to be influenced by pre‐chemical treatment. Cellulose nanofibrous membranes were fabricated from cellulose nanofibers dispersion on a porous support. A nanoporous structure with an extensive interconnected network of fine cellulose nanofibers was formed on the support substrate. The resulting membranes exhibited typical and high‐efficient UF performances with high water fluxes of up to 2.75 103 L/m2/h/bar. The membranes also displayed high rejections for ferritin and 10 nm gold nanoparticles with a reactive surface area capable of rapidly decolorizing methylene blue from its aqueous solution. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43544.  相似文献   

14.
Silver nanoparticles were prepared from a polyacrylonitrile (PAN)/N,N‐dimethylformamide solution of silver nitrate (0.05–0.5 wt %) with light treatment (xenon arc) to reduce Ag+ ions into Ag0. The formation of silver nanoparticles in the PAN solution and the effect of treatment time on the numbers of silver nanoparticles, their average diameter and size distribution were investigated by UV–visible spectroscopy. In addition, the average size of silver nanoparticles and their shapes in colloidal solution were determined by transmission electron microscopy images and found to be on the order of 10 nm. The resulting solution was electrospun into PAN nanofibers. An increase in the salt concentration led to decreases in the nanofiber diameter and bead numbers (determined by scanning electron microscopy images) and an increase in the crystallinity (confirmed by X‐ray diffraction patterns). A continuous rate of silver release from the nanofiber web was monitored by the atomic absorption technique. These nanofibers showed strong antibacterial activity against Pseudomonas aeruginosa. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010  相似文献   

15.
Hydroxyalkyl derivatives of polyaminostyrene (PAS), polyallylamine (PAA), and polyethyleneimine (PEI) containing a 2,3‐dihydroxypropyl moiety with a high degree of modification were synthesized. The chemical structures of the polymer transformation products were characterized with elemental analysis, Fourier transform infrared spectroscopy, 1H‐NMR spectroscopy, and 13C‐NMR spectroscopy in the solid state. PAS reacted with glycidol and formed poly[N‐(2,3‐dihydroxypropyl)aminostyrene] with a high degree of functionalization. PAA revealed primarily the graft polymerization of glycidol. In the case of PEI, primary amino groups allowed the formation of an N‐derivative of 3‐aminopropanediol‐1,2. The PAA‐based sorbent showed a high sorption capacity toward boron ions in both acidic and alkaline media. From the sorption isotherm data, the maximum sorption capacity of this sorbent at pH 4 was determined to be 3 mmol/g. The PAS‐based resin maintained a high capacity between pH 9 and 12; the optimum pH was 12. The sorption capacity was 1.7 mmol/g. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43939.  相似文献   

16.
The process of electrospinning is very suitable for obtaining fibers with a diameter on a nanometer scale. Such fibers can be spun from almost all kinds of known polymers, copolymers, and polymer blends. In this work, we present cellulose nanofibers obtained by the electrospinning process from spinning dopes containing cellulose dissolved in an N‐methylmorpholine‐N‐oxide/water system. Under different electrospinning process conditions, cellulose fibers, a nonwoven fiber network, and a cellulose membrane were obtained. The fibers were examined with scanning electron microscopy. The diameters of the fibers were in the submicrometer range. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1855–1859, 2005  相似文献   

17.
Nylon‐6,6 was grafted at the surface of glass and plasma‐treated Kevlar fibers for use in nylon–Kevlar thermoplastic composites. Hydroxyl and, in the case of Kevlar, amine end‐groups occur at the fibre surface, either as defects or due to the plasma treatment. These were used as anchor points for nylon‐6,6 step polycondensation. Fibers were subjected to successive dipping in adipoyl chloride/CH2Cl2 and aqueous hexamethylenediamine solutions in order to attach and grow high molecular weight polymer on the fiber surface. Grafted nylon was characterized by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance, differential scanning calorimetry and thermogravimetry. It was shown that no backbiting occurred during the first stage of the grafting process and that the polymer quantity increased linearly with number of passes, up to ∼50 passes for plasma‐treated Kevlar and 100 for glass fibers, after which polymer quantity remained constant, within experimental error, which was attributed to the onset of termination reactions. POLYM. COMPOS., 28:278–286, 2007. © 2007 Society of Plastics Engineers  相似文献   

18.
Nanofibers of n‐Butyl Acrylate/Methyl Methacrylate copolymer [P(BA‐co‐MMA)] were produced by electrospinning in this study. P(BA‐co‐MMA) was synthesized by emulsion polymerization. The structural and thermal properties of copolymers and electrospun P(BA‐co‐MMA) nanofibers were analyzed using Fourier transform infrared spectroscopy–Attenuated total reflectance (FTIR–ATR), Nuclear magnetic spectroscopy (NMR), and Differential scanning calorimetry (DSC). FTIR–ATR spectra and NMR spectrum revealed that BA and MMA had effectively participated in polymerization. The morphology of the resulting nanofibers was investigated by scanning electron microscopy, indicating that the diameters of P(BA‐co‐MMA) nanofibers were strongly dependent on the polymer solution dielectric constant, and concentration of solution and flow rate. Homogeneous electrospun P(BA‐co‐MMA) fibers as small as 390 ± 30 nm were successfully produced. The dielectric properties of polymer solution strongly affected the diameter and morphology of electrospun polymer fibers. The bending instability of the electrospinning jet increased with higher dielectric constant. The charges inside the polymer jet tended to repel each other so as to stretch and reduce the diameter of the polymer fibers by the presence of high dielectric environment of the solvent. The extent to which the choice of solvent affects the nanofiber characteristics were well illustrated in the electrospinning of [P(BA‐co‐MMA)] from solvents and mixed solvents. Nanofiber mats showed relatively high hydrophobicity with intrinsic water contact angle up to 120°. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4264–4272, 2013  相似文献   

19.
Boron nitride (BN) fibers were fabricated on a large scale through the melt‐drawn technique from low‐cost boric acid, NH3, and N2. Evolution of structure and properties of BN fibers during the fabrication process was studied by Fourier transform infrared (FT‐IR), X‐ray diffraction (XRD), scanning electron microscope (SEM), and X‐ray photoelectron spectroscopy (XPS). The mechanical properties of BN fibers were tested and analyzed. The results shown that both the mechanical properties and the crystallinity of BN fibers slightly increased with the temperature from 450 to 850°C, due to the combination of the fused‐B3N3. For BN fibers heat‐treated at 850 or 1000°C, the tensile strength (σR) and elastic modulus (E) were strongly increased because of the increase in crystallization of the BN phase. The meso‐hexagonal BN fibers with a diameter of 5.0 μm were fabricated at 1750°C, of which the tensile strength (σR) and elastic modulus (E) are 1200 MPa and 85 GPa, respectively. BN fibers with excellent mechanical properties and proper diameters were obtained by nitriding of green fibers during their conversion into ceramic.  相似文献   

20.
This study focused on the preparation of electrospun cross‐linked double‐network (DN) of agarose/polyacrylamide (PAAm) nanofibers. The agarose formed the first‐network that was physical‐linked by the agar helix bundles. After UV‐irradiation, the chemically crosslinked PAAm was formed as the second network. The resulting cross‐linked DN agarose/PAAm nanofibers were characterized by scanning electron microscopy (SEM), contact angle, attenuated total reflectance‐Fourier transform infrared spectroscopy (ATR‐FT‐IR), thermogravimetric analysis (TGA), and tensile test. SEM analysis shows the agarose/PAAM nanofibers present with the thickness of 187 nm. Agarose/PAAm nanofibers were showing FT‐IR spectral peaks at ~1660, 1590, and 1070 cm?1 indicating the presence of both agarose and polyacrylamide in the crosslinked DN Agarose/PAAm nanofiber sheet, it suggests the strong interaction and good compatibility between the two components. Agarose/PAAm nanofiber sheet was showing thermal stability close to the pure polyacrylamide. From the tensile test study, agarose/PAAm strength improved by 66.66% compared to the pure agarose. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42914.  相似文献   

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