A Solvent-Free Process for Preparing Conductive Elastomers by an In Situ Polymerization of Pyrrole

A solvent-free method for preparing electrically conductive polyurethane foams and elastomeric films is described. The method consists of impregnation of the oxidant into the foam through the sublimation of iodine, followed by in situ polymerization of pyrrole using pyrrole vapors to obtain a polypyrrole/polyurethane foam composite. Iodine serves as both the oxidant in the oxidative polymerization of pyrrole and the dopant for the resulting polypyrrole by forming a charge-transfer complex with the polymer. The conductivities of the composite foams ranged from 10 -1 to 10 -7 S/cm depending on the concentration of the oxidant incorporated in the iodine sorption step.