Polypyrroles, properties mechanical

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. 

The only polymer which has been subjected to systematic studies of mechanical properties is polypyrrole, and even here there are few data. Increasing the polymer molecular weight would be expected to lead to improved toughness, particularly in the very short-chain materials such as Kovacic polyphenylene. 

Lee [6] observed that when polyaniline or polypyrrole were N-functionalized with Wt-butoxy carbonyl, these materials displayed enhanced physical and mechanical properties with higher solubility and electrical conductivity than the corresponding nonfimctionalized counterparts. 

Composites of polypyrrole and poly(vinyl chloride) have been prepared by several groups (64-67). Polythiophene-poly(vinyl chloride) composites have also been prepared (68). The electropolymerization of pyrrole on poly(vinyl chloride)-coated electrodes yielded composites with mechanical properties (tensile strength, percent elongation at break, percent elongation at yield) similar to poly(vinyl chloride) (65) but with a conductivity of 5-50 S/cm, which is only slightly inferior to polypyrrole (30-60 S/cm) prepared under similar conditions. In addition, the environmental stability was enhanced. Morphological studies (69) showed that the polypyrrole was not uniformly distributed in the film and had polypyrrole-rich layers next to the electrode. Similarly, poly(vinyl alcohol) (70) poly[(vinylidine chloride)-co-(trifluoroethylene)] (69) and brominated poly(vinyl carbazole) (71) have been used as the matrix polymers. The chemical polymerization of pyrrole in a poly(vinyl alcohol) matrix by ferric chloride and potassium ferricyanide also yielded conducting composites with conductivities of 10 S/cm (72-74). 

The assembly of polypyrroles (PPy s) is an intricate process and determines the molecular structure and microstructure of the polymer obtained. This in turn influences the chemical, electrical, and mechanical properties of the material. It is impossible to optimize a single property of materials such as polypyrrole (PPy) in isolation. The chemical, electrical, and mechanical properties are inextricably linked. 

As with polypyrrole (PPy), the electrical, chemical, and mechanical properties of polyaniline (PAn) are inextricably linked. In addition, PAn has spectacular optical and chromic properties that distinguish it from other conducting electroactive polymers (CEPs). The current state of knowledge concerning properties of PAn is reviewed in this chapter. 

Polypyrrole electrochemically polymerized within a matrix resin electrically conducting material with improved mechanical properties over those of PPy Lindsey Street, 1985... 

R.A. Zoppi, at the Chemistry Institute of Campinas State University, performed a series of experiments on the S5mthesis of polypjrrrole in an EPDM rubber matrix, under the supervision of Professors M.A. de PaoH and M.I. Felisberti. The objective of the study was to obtain a product with electrical properties similar to those of polypyrrole and mechanical properties like those of EPDM rubber. Pol rpyrrole, a conducting polymer, is very brittle, which prevents its use in apphcations of practical interest. 

Sasso, C., Zeno, E., and Petit, M. (2010). Highty conducting polypyrrole/ cellulose nanocomposite films with enhanced mechanical properties, MaavmolMateK tj, 295(10], 934-941. 

Mechanical properties of PP/PPy nanocomposites were investigated by tensile tests. The effect of loading different amounts of polypyrrole nanopartides into thermoplastic polypropylene matrix and the changes in mechanical properties produced by incorporation of polypyrrole nanopartides were examined. In order to understand the effect of using sodium dodecylsulphate as dispersant in PP/PPy nanocomposites, identical tests were performed also for the nanocomposites prepared with dispersant. 

The changes in mechanical properties that are produced by loading different amounts of polypyrrole nanopartides can be well imderstood from stress-strain curves of PP/PPy nanocomposites which are illustrated in fig 8. through 3.8. As it is clearly observed in stress-strain curves of nanocomposites, addition of polypyrrole nanopartides makes... 

There have been several recent reports of corrosion studies involving polypyrrole or polypyrrole composites on iron or steel [217-226]. One study examined the influence of preparation method on the morphology, mechanical properties, and corrosion inhibition of PPy films on steel, concluding that the best mechanical properties (microhardness. Young s modulus, and elastic recovery) and the best corrosion protection were obtained for coatings electrodeposited at constant current and then thermally treated at 80°C for 1 d [219]. 

Herrasti, P., et al. 2004. Electrochemical and mechanical properties of polypyrrole coatings on steel. Electrochim Acta 49 (22-23) 3693. 

DellaSanta, A., A. Mazzoldi, C. Tonci, and D. DeRossi. 1997. Passive mechanical properties of polypyrrole films A continuum, poroelastic model. Mater Set Eng C-Bio S 5 101. 

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