Anionic copolymerization of styrenic-tipped macromonomers: A route to novel triblock-comb copolymers of styrene and isoprene

The following triblock-comb copolymers of isoprene (I) and styrene (S) - PS-b-(PI-g-PI)-b-PS, PS-b-[PI-g-(PI-b-PS)]-b-PS, and (PS-g-PS)-b-(PI-g-PI)-b- (PS-g-PS) (where PS is polystyrene and PI is polyisoprene) - with PS contents of 20-30% were synthesized with high-vacuum techniques and the anionic copolymerization of styrenic-tipped macromonomers with I and S. The macromonomers, prepared by the reaction of living PI or PS with 4-(chlorodimethylsilyl) styrene, were used without isolation. Molecular characterization by size exclusion chromatography, size exclusion chromatography/two-angle laser light scattering, and NMR spectroscopy indicated that the triblock-comb copolymers had high molecular and compositional homogeneity.