Stability of electrical properties of conducting polymer composites

The effect of slow cycle heating and cooling on the stability of electrical properties of two polymer composites- polypropylene/polypyrrole (PP/PPy) a nd polypropylene/carbon black (PP/CB) - was investigated. Conductivity in c omposites was measured in heating/cooling cycles in the temperature range f rom 16 degreesC to 105 degreesC in PP/PPy and to 125 degreesC in PP/CB, res pectively. It was found that the thermal treatment caused the decrease of P P/PPy conductivity while in case of PP/CB the treatment increased the elect rical conductivity. The positive effect was explained by increased crystall inity in the thermally treated composite.