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 shrinkability of the polymer blends was measured at room temperature (RT) and at a high temperature (HT) of 150 degrees C. Various parameters were tried for a correlation with shrinkability. Shrinkability goes up with the increase 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 sample was higher than that of a RT stretched sample, which was higher than that of the shrunk and original sample. The continuous cure characteristics, showed that the torque was increased with the rubber content. High temperature DSC demonstrated that the increase in AR-801 content decreased the stability and further HT processing increased the stability. SEM showed that the rubber phase was more elongated in the HT stretched sample compared to the RT stretched sample. In the shrunk sample the rubber phase was more globular. (C) 2000 John Wiley & Sons, Inc.