Reversible Addition-Fragmentation Chain Transfer Solution Polymerization of Polyvinyl Acetate

Polyvinyl acetate (PVAc) with low molecular mass(M_n < 1.0×10⁴) and narrow molecular mass distribution(M_w/M_n < 1.5) is synthesized by the reversible addition-fragmentation chain transfer (RAFT) solution polymerization using disulfide, isopropylxanthic disulfide (DIP) as chain transfer agent precursor and azodiisobutyronitrile (AIBN) as initiator. The structure and molecular mass of PVAc are studied by ¹H-NMR and GPC. Results demonstrate that the reaction conditions such as type of solvent, content of initiator and chain transfer agent, and polymerization temperature affect the polymerization conversion and controllability. The polymerization controllability in tetrahydrofuran is better than that in benzene. The polymerization rate and polydispersity index (PDI) increase with the increasing of the content of the initiator. The lower reaction rate and better controllability of the polymerization are obtained with the increasing of the content of chain transfer agent. The polymerization rate and PDI increase with the increasing of polymerization temperature.