Synthesis and Characterization of Star Polybutadiene by Anionic Living Polymerization with Chlorosilane Linking Agent

Abstract

MasterStar polymer is a branched polymer characterized by multiple linear chains linked to a central core. The unique chain architecture of star polymers imparts interesting physical properties depending on the molecular parameters such as the number of arms, molecular weight and polydispersity, but it is not possible to prepare truly homogeneous polymers even with a current state-of-art synthetic method. Therefore, precise molecular characterization is necessary to address the physical properties of the branched polymer with respect to the molecular parameters of the polymers. Size exclusion chromatography (SEC) is the most widely adopted technique for molecular characterization of polymers, however, it cannot characterize star polymers precisely, in particular, branched polymers. In the chapter 1, we synthesized 4-arm star polymers using anionic polymerization and a tetravalent chlorosilane compound as a linker. We characterized the 4-arm star polybutadiene by SEC and temperature gradient interaction chromatography (TGIC) to figure out the byproducts and to devise an efficient way to acquire high-purity star polymers.In the chapter 2, the formation of a chlorosilane-linked polybutadiene star is reported. The precursor arm material was made using anionic polymerization in cyclohexane. Size exclusion chromatography using multi angle laser light scattering was utilized for characterization. The star PB was synthesized by adjusting the equivalent ratio both polymeric anion and linking agent, this experiment can be effectively synthesized star polymer which has major target number of arms. It was found that four-arm star as a major product is formed within a few miniute after the addition of the chlorosilane linking agent