EFFECT OF POLYSTYRENE BLOCK ON THE RHEOLOGICAL AND STRUCTURAL-PROPERTIES OF HIGH-STYRENE-CONTENT SBRS

Abstract

The morphology and the rheological properties of linear gradual and random SBRs with high styrene content and narrow molecular weight distributions are examined. The copolymers were prepared by anionic polymerization in cyclohexane using n-butyllithium as initiator. The amount of polystyrene block content and the microstructure were varied by adding small amounts of a randomizer agent (THF). Our results show that microstructure plays a crucial role in the morphology and the rheological properties of these materials. Moreover, the morphology, examined by scanning electron microscopy, is strongly modified by heating and shearing the SBRs.