A NOVEL HIGH-CURRENT DENSITY SWITCHING EFFECT IN ELECTRICALLY CONDUCTIVE POLYMER COMPOSITE-MATERIALS

The electrical switching properties of electrically conductive polymer composites are studied at high current densities. It is shown that th e switching properties at high current densities are substantially dif ferent from those at low current densities which depend on a positive temperature coefficient of resistance effect. Experiments are describe d that show that this type of switching appears to be a general featur e in conductor-filled polymer composite materials and a qualitative mo del for the switching phenomenon is proposed. These results suggest th at conductor-filled polymer composite materials can provide a new nonm echanical way of rapidly limiting high power short-circuit currents. T his should have broad applications in the circuit protection industry. (C) 1997 American Institute of Physics.