ELECTRICAL-TRANSPORT IN 0-3 EPOXY-RESIN BARIUM-TITANATE CARBON-BLACK POLYMER COMPOSITES

Conductivity and dielectric constant of a three-component 0-3 composit e of epoxy resin-barium titanate-carbon black (0-3 composites are syst ems in which the filler is in the form of 0-dimensional (point-like, d isperse) particles in a three-dimensional polymeric matrix(1)) have be en investigated both at DC and the frequency range of 20-10(6) c/s. Th e effect of barium titanate concentration on percolation threshold, cr itical indices and the mechanism of conduction has been examined. An a ttempt was made to describe the electrical properties of composites Wi th models originally developed for two-component systems' dielectric-c onductor. With increasing barium titanate concentration the agreement of experimentally found frequency dependencies of conductivity and die lectric constant with models based on Debye's equation was found to de grade. An adequate description of electrical properties of composites' dielectric-ferroelectric-conductor should be based on the Havriliak-N egami equation. (C) 1998 John Wiley & Sons, Inc.