Studies on blends of ethylene vinyl acetate and polyacrylic rubber with reference to their shrinkability

Preferential crosslinking was introduced in the rubber phase of a blend of ethylene vinyl acetate (EVA) and polyacrylic rubber (AR-801). The heat shri nkability of the polymer blends was measured at room temperature (RT) and a t a high temperature (HT) of 150 degrees C. Various parameters were tried f or a correlation with shrinkability. Shrinkability goes up with the increas e in rubber content and is increased with increasing cure time in blends of a fixed ratio. The crystallinity of an HT (at 150 degrees C) stretched sam ple was higher than that of a RT stretched sample, which was higher than th at of the shrunk and original sample. The continuous cure characteristics, showed that the torque was increased with the rubber content. High temperat ure DSC demonstrated that the increase in AR-801 content decreased the stab ility and further HT processing increased the stability. SEM showed that th e rubber phase was more elongated in the HT stretched sample compared to th e RT stretched sample. In the shrunk sample the rubber phase was more globu lar. (C) 2000 John Wiley & Sons, Inc.