One-Step Synthesis of Dendritic Highly Branched Polystyrenes by Organotellurium-Mediated Copolymerization of Styrene and a Dienyl Telluride Monomer

摘要

Dendritic highly branched polystyrenes (HB-PSts) were prepared by a one-step copolymerization of dienyl telluride 6 and St in the presence of organotellurium chain transfer agent 2. The molecular weight (MW), dendritic generation, and branching density were easily controlled by the ratio of 2 to 6 to styrene (St) with maintaining mono-dispersity. The branching efficiency estimated by a deuterium-labeling experiment showed that 6 quantitatively (> 95 %) served as the branching point. The end group fidelity was high (ca. 90 %) as determined by the end group transformation to pyrene-derivative. Intrinsic viscosity of the HP-polystyrenes was significantly lower than that of linear polystyrenes and were easily tuned by the branching number and branching density. The method is compatible of various functional groups and chloro and acetoxy-substituted styrenes were also used as a comonomer. A tadpole block copolymer was also synthesized starting from linear PSI as a macroinitiator.