Radical ring opening and vinyl copolymerization of 2,3,4,5,6-pentafluorostyrene with 5,6-benzo-2-methylene-1,3-dioxepane: Synthesis and structural characterization using 1D and 2D NMR techniques

摘要

Radical ring opening polymerisation behaviour of 5,6-Benzo-2-methylene-1,3-dioxepane (BMDO) during its copolymerisation with 2,3,4,5,6-pentafluorostyrene (PFS) is reported using t-butyl peroxide (TBPO) conventional radical initiator. The reactivity behaviour of PFS for its copolymerisation is compared with that of the corresponding non-fluorinated monomer styrene. The presence of five fluorine atoms affected the course of polymerisation and led to the synthesis of well defined copolymers as compared to the formation of only homo poly styrene. Structural characterisation of the copolymers was done using 1D and 2D NMR spectroscopic techniques. The microstructural characterisation showed the formation of gradient copolymers with increased reaction time and/or increased amount of BMDO in the feed. The reactivity ratios for the copolymerisation of BMDO and PFS were determined using Kelen-Tudos method and was found to be r(BMDO) = 0.35 and r(PFS) = 9.9. Thermal stabilities of copolymers are also compared with that of the homopolymers.