EFFECT OF THE MOLD TEMPERATURE ON THE ELECTRICAL-PROPERTIES OF CARBON-BLACK-LOADED POLYSTYRENE SB BLOCK-COPOLYMER BLENDS/

The electrical resistivities of a carbon-black-filled styrene-butadien e block copolymer (SB) and their blends with polystyrene were measured as a function of carbon content for specimens compression-molded at 2 00 and 250 degrees C. The insulator-conductor point transition was gre atly influenced by the mold temperature. This behavior associated to t he scanning electronic microscopy investigations suggests the presence of some amount of the filler at the interface. A strong interaction b etween the filler and the polymer was also observed. The formation of bound rubber and a coherent rubber-filler gel depend on the molding co nditions and the carbon black content in the composites. (C) 1998 John Wiley & Sons, Inc.