Control of Molecular Weight and Tacticity in Stereospecific Living Cationic Polymerization of -Methylstyrene at 0 °C Using FeCl3-Based Initiators: Effect of Tacticity on Thermal Properties

The successful stereospecific living cationic polymerization of -methylstyrene (-MeSt) using FeCl3-based initiator systems at 0 degrees 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(-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 approximate to 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(-methylstyrene).