Poly -polypyrrole composite

Electrically conducting polystyrene/polythiophene, polystyrene/polypyrrole, polyacrylonitrUe/poly-pyrrole, polycarbonate/polythiophene, polycarbonate/polypyrrole composites are prepared by... 

Li X, Liu C, Xu D, Zhao C, Wang Z, Zhang G, Na H, Xing W (2006) Preparation and properties of sulfonated poly(ether ether ketone)s (SPEEK)/polypyrrole composite membranes for direct methanol fuel cells. J Power Sources 162 1-8... 

Electrosynthesized composites of poly(l,5-diaminonaphthalene) with polyaniline [146] and with polypyrrole [147] have been described and are reported to offer improved corrosion protection of iron. The corrosion-resistant properties of polyaniline and polypyrrole composite coatings electrochem-ically deposited on low carbon steel [148] were found to be strongly influenced by the applied potential and molar feed ratio of the monomers. 

Other polymer systems that have been studied with the electrochemical quartz crystal microbalance are poly(tetracycaoquinyldimethane) [91], poly(3-methylthiophene) [92], diheptylviologen bromide [93], polyani-line/Nafion composite films [94] and polypyrrole/3-(pyrrol-l-yl) propane sulphonate composites [95], and poly(pyrrole) composites with several anions [96-97]. 

The separation between oxidation and reduction peaks increases with the scan rate [159) due to a shift of the anodic peak, probably owing to the relatively slow formation of bipolarons. The cathodic peak also shifts with increasing scan rates, although to a lesser degree (Fig, 3). For polypyrrole/poly anion composites, in contrast, this separation is smaller, and the cathodic peak is more sensitive to increasing scan rate than the anodic peak [160]. 

Pron, A., Zagorska, M., Fabianowski, W., Ragnor, J. B., and Lefrant, S., Spectroscopic and morphological studies of a polypyrrole-poly(vinylalcohol) composite, Polym. Commm., 28, 193-195 (1987). 

Structural studies of polymer surfaces. Materials that have been studied include PMMA [239], PMMA-polypyrrole composites [240], polyfchloromethyl styrene) honnd 1,4,8,11-tetrazacyclotetradecane, polyfchloromethyl styrene) honnd thenoyl triflnoroacetone [241], poly(dimethyl siloxane)-polyamide copolymers [242], PS [243], ion-implanted PE [244], monoazido-terminated polyethylene oxide [245], polynrethanes [246], polyaniline [247], flnorinated polymer films [248], poly(o-tolnidine) [249], polyetherimide and poly benzimidazole [250], polyfnllerene palladinm [251], imidazole-containing imidazolylethyl maleamic acid-octadecyl vinyl ether copolymer [252], polyphenylene vinylene ether [253], thiophene oligomers [254], flnorinated styrene-isoprene derivative of a methyl methacrylate-hydroxyethyl methacrylate copolymer [255], polythiophene [256], dibromoalkane-hexaflnorisopropylidene diphenol and bisphenol A [257], and geopolymers [258]. 

Electrical properties have been reported on numerous carbon fiber-reinforced polymers, including carbon nanoflber-modified thermotropic liquid crystalline polymers [53], low-density polyethylene [54], ethylene vinyl acetate [55], wire coating varnishes [56], polydimethyl siloxane polypyrrole composites [50], polyacrylonitrile [59], polycarbonate [58], polyacrylonitrile-polycarbonate composites [58], modified chrome polymers [59], lithium trifluoromethane sulfonamide-doped polystyrene-block copolymer [60], boron-containing polyvinyl alcohols [71], lanthanum tetrafluoride complexed ethylene oxide [151, 72, 73], polycarbonate-acrylonitrile diene [44], polyethylene deoxythiophe-nel, blends of polystyrene sulfonate, polyvinyl chloride and polyethylene oxide [43], poly-pyrrole [61], polypyrrole-polypropylene-montmorillonite composites [62], polydimethyl siloxane-polypyrrole composites [63], polyaniline [46], epoxy resin-polyaniline dodecyl benzene sulfonic acid blends [64], and polyaniline-polyamide 6 composites [49]. 

The literature contains numerous references on two-step electrochemical syntheses of polypyrrole composites. Host substrates used include poly(vinylchloride)... 

In this study novel methods of preparing highly electrically conductive polymer composites and blends have been studied. A chemical diffusive polymerization process for preparing highly electrically conductive poly(vinylchloride)-polypyrrole composite has been developed. And a method of preparing conductive poly(vinylacetate)-polypyrrole composite film by casting on a substrate has also been developed. 

Preparation of Poly(vinylchloride)-polypyrrole Composite Film... 

Poly (vinylchloride)-polypyrrole composite film was prepared by allowing the oxidative polymerization to take place in PVC matrix with diffused pyrrole. The PVC film was immersed in a swelling solution containing pyrrole so that the pyrrole monomer could diffuse into the polymer matrix and then subsequently polymerized in an oxidative solutions containing oxidant in an binary solvent system of similar solubility coefficients with PVC film. Mixture of acetone, n-hexane and pyrrole was chosen as a diffusion solution because it yields highly conductive and transparent composite film with good processability. 

The poly(vinylchloride)-polypyrrole composite film was examined with SEM and TEM microscopes. It is clear with the TEM examination that the conducting layer exists... 

The morphology of poly(vinylacetate)-polypyrrole composite film is very different from that of polymer blend prepared from the solution polymerization. Polypyrrole aggregates are connected with each other in the former case, which results in a polypyrrole network throughout the composite, while polypyrrole aggregates are separated from each other in the latter case. It is expected in the former case that a spinodal decomposition occurs during the phase separation process because of sudden changes in the concentration of pyrrole and ferric chloride as well as the viscosity of poly (vinylacetate). These sudden changes are caused by the evaporation of solvent. 

The typical conductivity of the poly(vinylchloride)-polypyrrole composite film shows about 20 S/cm with the 50-60% transparency at 500 nm. The pure polypyrrole layer which is synthesized under the same conditions as that of the poly(vinylchloride)-polypyrrole composite measured with the thin disk pressed from the precipitate of the polypyrrole showed the electrical conductivity of about 250 S/cm. 

The poly(vinylacetate)-polypyrrole composite film also showed high electrical conductivity of about 10 S/cm which resulted from the polypyrrole network structure formed from the spinodal decomposition during the casting process. 

Fig. 2 Electrical conductivity vs. the content of polypyrrole (O) poly(vinylacetate)-polypyrrole composite film prepared from the solvent evaporation method, ( ) poly(vinylacetate)-polypyrrole composite prepared from the solution polymerization.

The process of preparing highly electrically conductive composite films of poly(vinylchloride)-polypyrrole as well as poly(vinylacetate)-polypyrrole have been studied. The solvent system of n-hexane, acetone, and pyrrole mixture offers effective swelling medium of PVC film for preparing the highly electrically conductive poly(vinylchloride)-polypyrrole composite film. The poly(vinylacetate)-polypyrrole composite film has been prepared from the solvent evaporation method. 

In the poly(vinylacetate)-polypyrrole composite film polypyrrole forms a network structure by spinodal decomposition and poly(vinylacetate) is cross-linked by ferric chloride during the polymerization process which results in excellent chemical stability of the composite. 

Skotheim et al. [286, 357, 362] have performed in situ electrochemistry and XPS measurements using a solid polymer electrolyte (based on poly (ethylene oxide) (PEO) [363]), which provides a large window of electrochemical stability and overcomes many of the problems associated with UHV electrochemistrty. The use of PEO as an electrolyte has also been investigated by Prosperi et al. [364] who found slow diffusion of the dopant at room temperature as would be expected, and Watanabe et al. have also produced polypyrrole/solid polymer electrolyte composites [365], The electrochemistry of chemically prepared polypyrrole powders has also been investigated using carbon paste electrodes [356, 366] with similar results to those found for electrochemically-prepared material. 

Polypyrrole/poly(ethylene-co-vinyl acetate) conducting composites with improved mechanical properties were prepared by a similar method [167], In addition, polyaniline/polystyrene [168] and polyaniline/poly(alkyl methacrylate) [169] composites have been synthesised. A solution of persulphate in aqueous HC1 was added to an o/w HIPE of polymer and aniline in an organic solvent, dispersed in aqueous SDS solution, causing aniline polymerisation. Films were processed by hot- or cold-pressing. 

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