Synthesis of End-Functionalized Star-Shaped Poly(methylthiirane)s

Abstract

Star-shaped poly(methylthiirane)s were prepared by ring-opening polymerization of methylthiirane with thiolate ions as initiators. As expected, the “arm first method” using 1,2,4,5-tetrakis(bromomethyl) benzene as a linking agent gave mixtures of tetra-, (tri) and di-armed polymers. The “core first method” with tri- and tetra-thiols as core components seemed to be a better method and gave polymers of different molar masses, varying from 800 to 60 000 g·mol–1 with narrow polymolecularity indices; but the presence of macromolecular disulfides – formed by oxidation of the thiolate ions – broaden the molar distribution. These disulfides could be reduced with lithium aluminium hydride. The star polymers could be end-capped with various functional groups through reaction of the thiolate end groups, either at the end of the polymerization or after acid regeneration from the thiol polymers.