Radical telomerization of vinyl acetate with chloroform. Application to the synthesis of poly(vinyl acetate)‐block‐polystyrene copolymers by consecutive telomerization and atom transfer radical polymerization

This paper demonstrates that radical telomerization and atom transfer radical polymerization (ATRP) can be combined in a two‐step procedure to prepare poly‐(vinyl acetate)‐block‐polystyrene (PVOAc‐b‐PSt) diblock copolymers. The first step consists in telomerizing VOAc with chloroform, leading to trichloromethyl‐terminated VOAc telomers CCl₃(VOAc)_nH. A detailed ¹H NMR analysis shows that nearly pure telomer structures are obtained over a broad range of DP_n values (up to at least 60 units). When ATRP of styrene is initiated with a model telomer adduct (CCl₃CH₂CH₂OAc), molecular weights increase linearly with monomer conversion and match theoretical values. Moreover, polydispersities are consistently low (1.22 < M_w/M_n < 1.38) throughout polymerization. Similarly, VOAc telomers (DP_n = 9 and 62) are good ATRP macroinitiators. The high purity of the resulting diblock copolymers is confirmed by GPC using RI/UV dual detection.