Abstract
The heat shrinkability of polymers is utilised in various applications -mainly in the field of encapsulation. Elastic memory is introduced into the system by means of an elastomeric phase. Here, blends of ethylene vinyl acetate (EVA) and epichlorohydrin were studied with reference to their shrinkability, by introducing crosslin king in the elastomer phase. It was found that an increase in elastomer content and cure time caused the shrinkage to increase. High temperature (H-T) stretched samples showed higher shrinkage than room tern perature (R-T) stretched ones. Generally the crystallinity of high temperature (H-T) stretched samples was higher than that of low temperature stretched ones which was again higher than that of the original unstretched samples. From high temperature DSC it was found that with increase in epichlorohydrin content, stability towards oxygen was decreased and for high temperature stretched samples, the stability was increased compared to the original unstretched and high temperature shrunk samples. But for H-T shrunk samples the first and second decomposition temperatures were lower and the rate of degradation was enhanced compared to unstretched samples and H-T stretched ones. SEM showed that H-T stretched samples were more elongated than R-T stretched ones.