Dynamic mechanical properties of styrene butadiene rubber and poly (ethylene-co-vinyl acetate) blends

TLDR: In this article, the effects of cross-linked and uncrosslinked styrene butadiene rubber/poly (ethylene-co-vinyl acetate) (SBR/EVA) blends were studied with reference to the effect of blend ratio, crosslinking systems, a compatibilizer viz. maleic-anhydride grafted poly [styrene-b-(ethyleneco-butylene)-b-styrene] (SEBS-g-MA), frequency and temperature.

Abstract: The dynamic mechanical behaviour of uncrosslinked and crosslinked styrene butadiene rubber/poly (ethylene-co-vinyl acetate) (SBR/EVA) blends was studied with reference to the effects of blend ratio, crosslinking systems, a compatibilizer viz. maleic-anhydride grafted poly [styrene-b-(ethylene-co-butylene)-b-styrene] (SEBS-g-MA), frequency and temperature. The two separate tan δ peaks, obtained during DMA, indicated the immiscibility of SBR/EVA system. The damping properties increased with SBR content for uncrosslinked and crosslinked blends. In the case of crosslinked systems, depending upon the type of crosslinking agent used, the glass transition temperature (T g) of SBR phase has been found to be shifted to higher temperatures. The damping characteristics of the blends were observed to be affected by the variations in frequency. The addition of the compatibilizer improved the storage modulus and reduced the damping properties. These results have been correlated with the morphology of the blends, attested by scanning electron micrographs. The activation energy for glass transition has been computed. The experimental data on storage modulus were compared with theoretical predictions.