Search

In this paper, an environmentally friendly method to produce electrically conductive and antibacterial silver nanoparticles (AgNPs) coated polyamide (PA) yarns was reported. A new AgNPs coated composite PA yarn has been synthesized in the presence of carboxy methyl starch (CMS) reducing agent. Silver nitrate (AgNO3) was reduced on the surface of the PA fibers which allowed formation of silver nanoparticles. Scanning electron microscopy (SEM) images indicated distribution of silver nanolayer formation on the composite fiber surface. Electrical conductivity of composite yarns was measured by four point probe technique and was changed from 1.015x10-5 to 1.282x100 S/cm. The ecofriendly coating method used in this study enabled to produce multifunctional composite PA yarns with antistatic and antibacterial properties. [ABSTRACT FROM AUTHOR]

ABSTRACT In this study, acrylic-based conductive polymeric composite thin films were prepared by in situ chemical polymerization of pyrrole (Py) in the case of ammonium persulfate (APS) and iron(III) chloride (FeCl3). Composite thin films were produced by the solution casting method. The effect of polypyrrole (PPy) content and the type of oxidant on the morphological and dielectric properties were investigated. Temperature- and frequency-dependent dielectric properties were also studied in a frequency domain starting from 0.01 Hz to 10 MHz and in a temperature domain from 35 to 195°C. The results revealed that the dielectric constant and dielectric loss increased, whereas temperature and the highest dielectric values were obtained in the case of APS. The density of interconnected pores enwrapped with PPy under the surface improved the electrical/dielectric properties of the composite thin films. [ABSTRACT FROM AUTHOR]

In this study, nanostructured polypyrrole (PPy)-coated cotton textiles were produced by in situ chemical oxidative polymerization and dielectric/electrical properties of PPy-coated cotton fabrics were presented in the low- and high-frequency regions. The conductive cotton fabrics showed a relatively high dielectric constant in the low- and radio-frequency region. The dielectric constant and dielectric loss for all fabrics presented relatively high values at low frequency and were found to decrease with the frequency. The influence of the PPy content and the type of dopant and oxidant on the morphological, dielectric/electrical and thermal properties of the cotton fabrics was investigated. It was found that the type of dopants and oxidants had a noticeable effect on the electrical/dielectric and morphological properties. The frequency dependence of AC conductivity, dielectric constant, dielectric loss and electric modulus were analyzed in the frequency range from 0.1 kHz to 10 MHz. The nanofiber network morphology of coated fabrics produced by dodecylbenzenesulfonic acid sodium salt improved the electrical/dielectric and thermal properties of cotton composites. [ABSTRACT FROM PUBLISHER]

Chemical oxidative polymerization of N-Methyl Pyrrole (NMPy) by cerium(IV) on Poly(Acrylonitrile-co-Vinyl Acetate) matrix in N,N-dimethylformamide (DMF) was performed. Electrospinning technique was used for the preparation of P(AN-co-VAc) solutions with uniformly distributed Poly(N-Methyl Pyrrole) (PNMPy) nanoparticles. In the presence of PNMPy, a new absorption band appeared at 1312 cm-1 which corresponds to CH in plane vibration peak. The dielectric properties of nanofiber composites were evaluated on the basis of the complex permittivity. The SEM and AFM images of composite nanofibers showed that the PNMPy nanoparticles with the dimensions of 20-40 nm were distributed homogeneously. [ABSTRACT FROM AUTHOR]

In this study, free radical copolymerization of acrylonitrile (AN)-vinyl acetate (VAc) was performed for five different feed ratio of VAc (wt %) by using ammonium persulfate (APS) in the aqueous medium. The effect of VAc content on the spectrophotometric and thermal properties of AN-VAc copolymers was investigated by Fourier Transform Infrared-Attenuated Total Reflectance spectrophotometer (FTIR-ATR), differential scanning calorimeter (DSC), and thermal gravimetric analyzer (TGA). Thermal stability of homopolymer of AN is improved after being copolymerized. The electrospun P(AN- co-VAc) nanofibers were fabricated and the effect of VAc content on the morphologic properties of nanofibers was studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The viscosity of the solution had a significant effect on P(AN- co-VAc) electrospinning and the nanofiber morphology. The average diameters of P(AN- co-VAc) nanofibers decreased 3.4 times with increasing feed ratio of VAc wt %. The P(AN- co-VAc) electrospun nanofiber mats, with the feed ratio of 30 wt % VAc, can be used as a nanofiber membrane in filtration and as a carbon nanofiber precursor for energy storage applications due to high surface to volume ratio, high thermal stability, homogeneous, and thinner nanofiber distribution. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 [ABSTRACT FROM AUTHOR]

The oxidative polymerization of pyrrole (Py) by cerium(IV) on Poly(Acrylonitrile- co-Vinyl Acetate) matrix was performed. Nanofibers were obtained from this solution by the electrospinning method. A new absorption band was observed corresponding to the CH in plane vibration of polypyrrole (PPy) by Fourier transform infrared-attenuated total reflectance spectrophotometric analysis. A linear relationship was determined between the absorbance ratios of functional groups corresponding to the conjugated polymeric units and initial Py concentrations in the presence and absence of Py. Scanning electron microscope images indicated that the diameters of nanofibers were dependent on PPy content and that the average nanofiber diameters were reduced with increasing the initially added Py concentration. The alternating current conductivity of nanofibers was increased with frequency, particularly in the higher frequency region (> 105 Hz). [ABSTRACT FROM PUBLISHER]