Polymerization of Vinyl Acetate Promoted by Iron Complexes

Polymerization of vinyl acetate (VOAc) was carried out using CCl 4 as the initiator in the presence of the Fe(OAc) 2 /PMDETA (PMDETA = N, N,N ‘,N ‘ ‘,N ‘ ‘ -pentamethyldiethylenetriamine) complex. Poly(vinyl acetate) with a wide range of molecular weights was synthesized in a predictable fashion in high yields (ca. 70%) by varying the ratio of the initial concentrations of monomer and initiator. The resulting poly(vinyl acetate) ( M n = 3600 and M w / M n = 1.81) was used as an efficient macroinitiator for the synthesis of block copolymers with n -butyl acrylate ( M n = 11 000 and M w / M n = 1.41) and styrene ( M n = 24 300 and M w / M n = 1.42) using typical atom transfer radical polymerization (ATRP) catalytic systems. However, more detailed kinetic studies revealed that the VOAc polymerization did not obey ATRP behavior but was a redox-initiated radical telomerization with CCl 4 acting as both the initiator and the main-chain transfer agent. Block copolymerization was due to the chain extension with the trichloromethyl end groups.