Characterization of polypyrrole coated latex particles by admicellar polymerization

Abstract

Polypyrrole (PPy) is known to be a good conductive polymer; however, its processability is relatively poor due to its brittleness and high cohesive strength. Admicellar polymerization is based on the use of a surfactant template and has been shown to successively form fine coating on solid substrates. In this work, a soft polymer substrate was used, i.e. natural rubber latex particles. The amount of PPy coated onto the latex particles was varied from 0.1-5wt%. The particles were mixed with polypyrrole at various concentrations 10-90 wt% their blends were characterized for morphology, mechanical and thermal properties as well as the coated particles. No residue of free pyrrole monomer was observed. The thermal resistance of the admicellar PPy coated latics increased with PPy content. However, the thermal resistance of PPy/admicellar PPy coated latices blends showed an inverse trend, i.e. a lower degradation temperature than those of the pure components. The best properties were obtained for the one made with a salt addition. Tensile properties of the coated latices were better with added PPy. Rheological tests showed that the new PPy composites were processable having moderate viscosity and elasticity. The morphology of the coated latex and its blends were investigated using optical microscopy. A thin coverage of PPy on the substrate was observed with good distribution.