Synthesis of dihydroxy terminated poly(chloroethyl vinyl ether)s by “living” cationic polymerization: evidences for side reactions and their control

This paper reports on the synthesis of dihydroxy terminated poly(chloroethyl vinyl ether)s (PCEVE) via bifunctional living cationic polymerization. The bifunctional chain initiator is obtained by reacting malonaldehyde bis(diethyl acetal) with trimethylsilyl iodide (TMSI) to form the corresponding di‐α‐iodo ether derivative. The polymerization of chloroethylvinyl ether is then triggered by ZnCl 2 . The direct transformation of active ends into aldehyde terminals, as well as their derivatization into hydroxy groups, is described. The synthesis of high molar mass ditelechelics by bifunctional polymerization provides evidence for the occurrence of a monofunctional side initiation. The latter has been attributed to the hydrolysis of TMSI by adventitious water, which leads to the in situ formation of hydrogen iodide. In order to trap hydrogen iodide, the influence of different additives, bulky amines, metals and alkylaluminiums, was investigated. Therefore, in the presence of alkylaluminiums, it is possible to obtain a clean bifunctional polymerization up to relatively high molar mass ditelechelic PCEVE (M̄ n = 33000 g/mol, M̄ w /M̄ n = 1.11).