Modification of morphology of polycarbonate/thermoplastic elastomer blends by supercritical CO2

The effect of supercritical CO2 on the morphological features of blends of polycarbonate and a commercial thermoplastic elastomer was investigated. The as-prepared films of the blend showed phase separated domains of the elastomer. With the combination of pressure and temperature, the large domains were “burst” into smaller domains. Temperatures higher than the critical temperature are required to cause any change in the morphology. The size distribution of the elastomer domains is effectively narrowed by the supercritical CO2 treatment. The time of exposure also plays a role. It was also seen that above 60 °C, crystallization of polycarbonate begins. Based on the previous work on this system, it is proposed that enhancement of elongation, Young’s modulus and abrasion resistance would occur due to the reduction in the domain size and distribution.