PMMA-BLOCK-POLYISOBUTYLENE-BLOCK-PMMA PREPARED WITH ALPHA,OMEGA-DILITHIATED POLYISOBUTYLENE AND ITS CHARACTERIZATION

A triblock copolymer of PMMA and polyisobutylene(PIB), PMMA-block-PIB-block-PMMA, was prepared by anionic polymerization of methyl methacrylate initiated with alpha, omega-dilithiated poly(isobutylene) diisobutylate in tetrahydrofuran at -60-degrees-C. The molecular weight distribution of the block copolymer was close to that of the starting PIB. The stereoregularity of PMMA block was predominantly syndiotactic. Proton spin-lattice relaxation time and solution viscosity of the block copolymer in acetone, which is non-solvent for PIB, indicate that the block copolymer forms rigid spherical particles. Stereocomplex formation with isotactic PMMA was also studied.