Star Polymer Synthesis Using Hexafluoropropylene Oxide as an Efficient Multifunctional Coupling Agent

摘要

Well-defined polyisoprene three-armed star polymers (PI_3) were synthesized through a combination of living anionic polymerization and an efficient coupling process using hexafluoropropylene oxide (HFPO).Anionic polymerization of isoprene followed by termination with HFPO yielded three-armed stars with narrow molecular weight distributions.Under optimized conditions,at least 97% of the chains can be coupled.Molecular characterization of the star polymers (SEC,NMR and IR spectroscopy,and MALDI-TOF mass spectrometry) gave data consistent with the star structure and proposed mechanism of formation.The effects of HFPO concentration and the molecular weight of the arm precursors on the extent of star polymer formation were investigated.End-functionalized polyisoprene stars were also prepared and have potential application as trifunctional precursors to branched block copolymers.