Preparation of block copolymer SBSIS having various polystyrene block lengths via anionic polymerization and the properties research

Two types of linear pentablock copolymers SBSIS, namely, ends-big and middle-big type were prepared by anionic polymerization of styrene (St), isoprene (Ip) and 1,3-butadiene (Bd) in a nonpolar solvent. Various samples having a number average molecular weight (Mn) of 60,000 g/mole were synthesized and characterized. The correlation between molecular structure and characteristic properties allows us to understand the effect on physical properties of important parameters such as styrene content, linking method, monomer proportions, and magnitude of end segment.