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11.
Preparation of conductive polypyrrole (PPy) composites under supercritical carbon dioxide conditions
Electrically conductive composites were prepared via the chemical oxidative polymerization of the pyrrole monomer in polystyrene
(PS) and zinc neutralized sulfonated polystyrene (Zn-SPS) films under supercritical carbon dioxide (SC-CO2) conditions. The strong swelling effect of SC-CO2 made polypyrrole (PPy) particles not only form on the surface, but also become incorporated into the film, resulting in a
homogeneous structure with a relatively higher conductivity. By comparison, the composite prepared in aqueous solutions shows
a skin-core structure and a conductivity of 3 to 4 orders of magnitude lower than that of the former due to the diffusion-controlled
process of the pyrrole monomer. The percolation thresholds of PS/PPy and Zn-SPS/PPy composites were 6.2% and 2.7% of the volume
fraction of PPy, respectively, much lower than the theoretically predicted value of 16%. Moreover, the conductive composites
prepared under SC-CO2 conditions showed higher thermal stability, especially in the high-temperature region.
Translated from Chemical Journal of Chinese Universities, 2006, 27(4): 771–774 (in Chinese) 相似文献
12.
A.?AsanEmail author M.?Kabasakaloglu M.?L.?Aksu 《Russian Journal of Electrochemistry》2005,41(2):154-158
In this study, the coverage conditions of mild steel with polypyrrole (PPy) were investigated. It was observed that the surface was passive up to 0.6 V, to the oxidation potential of pyrrole in oxalic acid solution. The PPy coverage was obtained with 0.1 M oxalic acid + 0.2 M pyrrole. A passivity mechanism supported with current potential curves was proposed. The PPy deposition was also investigated according to pyrrole and oxalic acid concentrations by successive voltammetric scans.This article was submitted by the authors in English.From Elektrokhimiya, Vol. 41, No. 2, 2005, pp. 175–180.Original English Text Copyright © 2005 by Asan, Kabasakaloglu, Aksu.This revised version was published online in April 2005 with corrections to the article note and article title and cover date. 相似文献
13.
Rita Aparecida Zoppi Maria Isabel Felisberti Marco-Aurelio De Paoli 《Journal of polymer science. Part A, Polymer chemistry》1994,32(6):1001-1008
This work describes the preparation of polypyrrole and EPDM rubber blends, PPy/EPDM, by the sorption of pyrrole (vapor phase) in an EPDM matrix containing CuCl2. We investigated the effect of the oxidant particle-size on the sorption and polymerization equilibrium, electrical conductivity, and mechanical properties of the blends. Independently of the CuCl2 concentration and polymerization time, the polypyrrole weight fraction in the blend, Xppy, increases when the oxidant particle-size in changed from 150–250 μm to smaller than 106 μm. For blends containing 50 phr of CuCl2, obtained following 72 h of exposure to pyrrole, an increase in the Young's Modulus (from 2.2 ± 0.2 to 3.9 ± 0.6 MPa) and an increase in the electrical conductivity (from 10?9 to 10?7 S cm?1) was observed when the oxidant particle-size was decreased. Infrared spectroscopy, thermogravimetric analysis, scanning differential calorimetry, and scanning electron microscopy were used in sample characterization. © 1994 John Wiley & Sons, Inc. 相似文献
14.
DC-plasma-polymerized pyrrole (PP-Py) films deposited on metals were extensively characterized by Time-of-Flight Secondary
Ion Mass Spectrometry (TOF-SIMS), Reflection-Absorption IR Spectroscopy (RAIR), X-ray Photoelectron Spectroscopy (XPS), Scanning
Tunneling Microscopy (STM), Glow Discharge Optical Spectroscopy (GDOS), electrical conductivity (ASTM Franklin test), and
contact angle measurements. TOF-SIMS and RAIR showed no spectroscopic evidence of the presence of the pyrrole ring structure
in any of the plasmadeposited films. The major parameter that affected their composition was found to be the pressure. Films
deposited at low pressure were less hydrogenated than those polymerized at high pressure or in remote plasma conditions. Although
all deposits oxidized slowly in air, their surface energy remained low over an extended period of time. The electrical conductivity
of the PP-Py films was in the range of 10−3–10−4 S/cm, i.e., higher than that of amorphous carbon films. 相似文献
15.
Tamm J. Johanson U. Marandi M. Tamm T. Tamm L. 《Russian Journal of Electrochemistry》2004,40(3):344-348
Experimental and theoretical methods have been used for characterization of the properties of polypyrrole films. The AFM studies show that the morphology of polypyrrole (PPy) films on polycrystalline gold electrodes at the first stages of synthesis depends on the structure of the metal surface. It was established that mobility of anions depends remarkably on the rate of electrodeposition of the polymer film. If PPy film was deposited at relatively low current density, mobility of ClO-
4 anion was not high enough to guarantee electroneutrality during redox cycling and cations take part in this process especially when Li+ cations were replaced by more mobile + cations. Semiempirical (AM1 and PM3) quantum-chemical methods were used for theoretical studies. It was established that different size and charge of the anions together with the variation in doping levels give rise to a different optimal conformation of oligopyrrole cations which, in turn, define the resulting polymer to be either all-anti (common linear chains) or all-syn (formation of helical structures) or a combination of the two. 相似文献
16.
O. Brafman J. Poplawski E. Ehrenfreund Z. Vardeny J. Tanaka H. Fujimoto 《Molecular Crystals and Liquid Crystals》2013,570(1):363-366
Resonant Raman Scattering and doping induced IR absorption are explained in terms of amplitude modes of the 1-d gap. The RRS frequencies and relative intensities of the renormalized phonon lines at the various concentrations are readily obtained. 相似文献
17.
Abstract The changes in the characteristics of vibrational and optical properties of the conducting form of polypyrrole under pressure is studied. 相似文献
18.
19.
Mohamed Laabd Lahoucine Atourki Hafsa Chafai Mohammed Bazzaoui Maria Elamine 《Journal of Dispersion Science and Technology》2017,38(9):1227-1233
This study sheds light on the removal of humic acid by-products (trimellitic and pyromellitic acids; TMA and PMA, respectively) from aqueous solution using conducting polypyrrole (PPy) as an effective adsorbent. The effects of experimental factors including contact time, solution pH, initial concentration, adsorbent dose, and temperature were systematically investigated. The pseudo-second-order kinetic model provides the best correlation with adsorption experimental data. The equilibrium adsorption was well described by the Langmuir model with maximum mono-layer adsorption capacities of 47.62 and 71.43?mg?g?1 for TMA and PMA, respectively. The analysis of thermodynamic parameters indicated that the adsorption process was spontaneous and endothermic in nature. In addition, we investigated the adsorption mechanism using the density functional theory (DFT) calculations. The TMA and PMA were physisorbed on the PPy surface through the formation of hydrogen bonds between carboxylic groups of adsorbate molecules and the amino group of the adsorbent. The calculated theoretical data were in good agreement with experiments. 相似文献
20.
Polypyrrole‐zirconium complex has been synthesized by reacting 2‐amino‐3,4‐dicyano‐5‐mercaptopyrrole with zirconium nitrate in absolute ethanol under reflux for 24 h. The product has been characterized by elemental analyses, FTIR spectroscopy, in addition to thermal analysis (TGA and DSC) and its solubility has been investigated. The DC electrical conductivity variation of polypyrrole‐zirconium complex has been studied in the temperature range 300–500 K after annealing for 24 h at 100°C and doping with I2, FeCl3 and CuCl2 · H2O for comparison. An attempt has been made to interpret the DC electrical conductivity behavior and thermal properties to chain length, dopant used, polymer structure and attached groups. 相似文献