Functionalized Polyisobutylene and Polyisobutylene-Based Block Copolymers by Mechanistic Transformation from Cationic to Radical Process

The strategy for the preparation of polyisobutylene-based block copolymers via mechanistic transformation from cationic to radical polymerization is reported. This strategy involves the synthesis of 2-bromo-2-methylpropanoyl-terminated difunctional polyisobutylene macroinitiator (BiBB-PIB-BiBB) via consecutive cationic polymerization, in situ preparation of hydroxyl-terminated polyisobutylene and its acylation by 2-bromo-2-methylpropanoyl bromide. The Mn₂(CO)₁₀−triggered photo-induced radical polymerization of styrene in bulk using this macroinitiator leads to the formation of multiblock copolymer, while predominantly triblock copolymer is generated during the polymerization of methyl methacrylate. The possibility to functionalize the polyisobutylene by pyrene via photo-induced radical addition of 1-bromomethyl pyrene in the presence of Mn₂(CO)₁₀ is also demonstrated in this work.