Relationship between Microphase Separation Structure and Physical Property of Thermoplastic Elastomer Mixtures

Abstract

We developed a thermoplastic elastomer by blending symmetric styrene-isoprene-styrene (SIS) and asymmetric SIS block copolymers. The elastomer is used as an elastic film because it has superior physical properties, such as a high modulus and recovery compared to previous symmetric SIS polymers which have been used as adhesive and glue materials. The phase-separated structure of the elastomer was investigated by small angle X-ray scattering, transmission electron microscopy, and self-consistent filed theory simulation to elucidate the reason for the superior physical properties. We found randomly distributed large and small size styrene domains due to macro phase separation in the pressed films. Moreover, it became clear that the processing conditions strongly affect the phase-separated structure.