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.

This study reports a new method for polyisobutylene (PIB)-based block copolymers. It utilizes a difunctional PIB macroinitiator prepared via cationic polymerization and acylation. Photo-induced radical polymerization of macroinitiator with Mn2(CO)10 forms multiblock copolymers with styrene and triblocks with methyl methacrylate. Additionally, this work demonstrates the efficient functionalization of PIB with pyrene moieties via photoinitiated radical addition. image