Synthesis of random and block copolymers of vinyl chloride and vinyl acetate by RAFT miniemulsion polymerizations mediated by a fluorinated xanthate

摘要

Reversible addition-fragmentation chain transfer miniemulsion (co)polymerizations of vinyl acetate (VAc) and vinyl chloride (VC) are conducted in the presence of a fluorinated xthanate (X1). VAc miniemulsion polymerization can be well controlled by X1, and PVAc with small polydispersity index (PDI, <1.20) are obtained. X1 also shows well mediative effect to VC-VAc miniemulsion copolymerization, while the PDI of VC-VAc copolymer is greater than that of PVAc since a chain transfer rate to VC is greater than that to VAc. PVAc-b-PVC copolymers are synthesized by VC miniemulsion polymerizations mediated by X1-terminated PVAc. PDIs of PVAc-b-PVC copolymers are greater than that of PVAc and VC-VAc random copolymers with close monomer compositions, and increase with the increase of VC conversion. This is caused by the increased chain transfer to monomer and the formation of monomer-rich and polymer-rich phases during the VC polymerization stage. As-prepared PVAc-b-PVC copolymers exhibit a micro-phase separated morphology. (c) 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45074.