Preparation of polyisobutene-graft-poly(methyl methacrylate) and polyisobutene-graft-polystyrene with different compositions and side chain architectures through atom transfer radical polymerization (ATRP)

Polyisobutene-graft-poly(methyl methacrylate) and polyisobutene-graft-polystyrene with controlled compositions and side chain architectures were prepared through atom transfer radical polymerization (ATRP). Poly[isobutene-co-(p-methylstyrene)-co-(p-bromomethylstyrene)] (PIB) was used as a macroinitiator in the presence of CuCl or CuBr as a catalyst and dNbpy as a ligand. The compositions were controlled by the conversion of the monomer with polymerization time. The molecular weight distributions of the side chains were controlled through ATRP in the presence/absence of a halogen exchange reaction. DSC and DMA measurements showed that graft copolymers have two glass transition temperatures suggesting microphase separated behavior, which was also confirmed by SAXS measurements. The phase and dynamic mechanical behaviors were strongly affected by the compositions and/or the side chain architectures. The properties of the graft copolymers were controlled in a wide range leading to toughened glassy polymers or elastomers. © Wiley-VCH Verlag GmbH, 2001.