Control of molecular weight and tacticity in stereospecific living cationic polymerization of α-methylstyrene at 0 °c using FeCl 3-based initiators: Effect of tacticity on thermal properties

Abstract

The successful stereospecific living cationic polymerization of α-methylstyrene (α-MeSt) using FeCl3-based initiator systems at 0 °C is reported. Linear first-order ln([M]0/[M]) vs. time and linear molecular weight vs. conversion plots suggest that the polymerization is living in nature, which is further confirmed from successful chain-extension experiments. Poly(α-methylstyrene)s of varying syndiotacticities (59.1% to 79.2%) and controllable molecular weights (4300-32 100 g mol-1) with moderately narrow polydispersity indices (PDIs ≈1.3) are synthesized simply by varying the monomer-to-initiator ratio ([M]0/[I]0). A possible mechanism for this stereospecific polymerization is proposed. The glass-transition temperature and thermal-decomposition temperature depend on the syndiotacticity of poly(α-methylstyrene). Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.