Cationic polymerization of α‐methylstyrene in dichloromethane initiated with system 2,5‐dichloro‐2,5‐dimethylhexene‐BCl3. II. Continuous addition of monomer into initiator, quasiliving polymerization

Abstract A slow continuous addition of dichloromethana solutions of α‐methylstyrene (α‐MeSt) into a dichloromethane solution of 2,5‐dichloro‐2,5‐dimethylhexane (DDH) with BCI3 (initiating system II) prepared in advance resulted, in the temperature range between −20 and −40°, in a quasilving polymerization of α‐MeSt. At −20°C and a 100% conversion a polymer with a very narrow molecular weight distribution is formed, M̄w/M̄n ‐ 1.1. Quasiliving polymerization of α‐MeSt has not been achieved with freshly prepared dischloromethane solutions of DDH with BC3 (initiating sytem I), or with solutions of BCI3 alone (initiating system III). Polarity of the polymerization medium affected molecular weight distribution (MWD) of the polymer, and the polydispersity index decreased with decreasing polarity. MWD of the polymer samples were studied by the GPC method, the structure of poly (α‐methylstyrene) (Pα‐MeSt) was investigated by the 1H‐NMR analysis