Conductive IPN based on polypyrrole and silicon crosslinked styrene-isoprene-styrene triblock copolymer

The conducting interpenetrating polymer network (IPN) is prepared by sequential crosslinking of tetrethyl orthosilicate (TEOS) with acrylic acid grafted styrene-isoprene-styrene triblock copolymer (SIS) and polypyrrole doped with dodecylbenzenesulfonic acid (DBSA). The resulting IPN not only has good conductivity, but also exhibits far superior thermal stability. Various factors affecting the properties of conductive IPNs are investigated. The amounts of water and TEOS used have a profound effect on the conductivity. Significantly, under appropriate experimental conditions, a conductive IPN with conductivity as high as that of pure PPyDBSA has been prepared. Heating the conductive IPNs to 140 degrees C has generally caused the conductivity to decrease. However, samples with conductivity relatively unaffected by the heat treatment can be prepared with proper selections of H2O/TEOS ratio. The effect of heating on the conductivity is discussed. All the IPNs have excellent thermal stability as clearly shown by the results of thermal gravitational analysis (TGA). The morphologies of the IPN films are investigated using a scanning electron microscope (SEM). (C) 1999 Elsevier Science Ltd. All rights reserved.