Metal oxide-polymer thermistors

Composites consisting of semi-crystalline or amorphous polymers and a conducting metal oxide filler, V₂O₃, have been prepared. They exhibit relatively low room temperature resistivities, (PTC) of resistance effects of up to nine orders in magnitude, and an NTC transition near -100' C. A previously proposed model that describes the resistivity behaviour of metal-insulator composites as a function of both temperature and filler concentration has been applied to V₂O₃-polyethylene and V₂O₃-rigid epoxy composites. The predictions of this model are then compared with the experimental behaviour of the composites. In addition, SEM micrographs of the composites are shown to illustrate the wetting characteristics of the various polymers on V₂O₃.