EFFECT OF HAF CARBON-BLACK FILLER ON CHEMORHEOLOGICAL BEHAVIOR OF POLY(ACRYLIC ACID) EPOXIDIZED NATURAL-RUBBER BLEND

Brabender-mixed blends of poly( acrylic acid) (PAA) and epoxidized nat ural rubber (ENR) were extruded through the capillary in a Monsanto pr ocessability tester, and the capillary pressure versus extrusion time plots were recorded. Constancy in capillary pressure with extrusion ti me was observed in the case of PAA/ENR blend; but the same blend, fill ed with HAE carbon black filler, shows a steady increase in capillary pressure with extrusion time. In presence of a free radical acceptor l ike thiophenol, the rate of capillary pressure rise decreases. Measure ments of physical properties, swelling studies, and scanning electron microscopy photomicrography of the extrudates indicates the occurrence of a chemical interaction between physisorbed ENR and chemisorbed PAA . (C) 1997 John Wiley & Sons, Inc.