The effect of mercapto-modified ethylene-vinyl acetate (EVA) on curing parameters, mechanical properties, and thermal properties of vulcanized styrene-butadiene rubber (SBR)/EVA blends

The effect of EVA functionalized with mercapto groups (EVALSH) on the compatibilization of SBR and EVA copolymer blends was investigated in vulcanized systems based on sulfur or dicumyl peroxide (DCP). The presence of EVALSH resulted in an improvement of the tensile properties, indicating the reactive compatibilizing effect of this compound. The best mechanical performance was achieved with the sulfur-curing system for both compatibilized and noncompatibilized blends. The blend systems were also analyzed by scanning electron microscopy, differential scanning calorimetry, and dynamic-mechanical analysis. The crystallinity of the EVA phase was significantly affected by the presence of the EVALSH, whereas no substantial change was detected on the damping properties or the glass transition temperature of the SBR phase. Considering the aging properties, the presence of EVALSH increases the thermal stability of the blends vulcanized with DCP. (C) 2002 Wiley Periodicals, Inc.