Poly(styrene-b-isobutylene-b-styrene) block copolymers produced by living cationic polymerization - I. Compositional analysis

Poly(styrene-b-isobutylene-b-styrene) block copolymers made through control led-living cationic polymerization using the Bu-t-m-DCC-TiCl4 initiating sy stem in 60/40 (v/v) hexane-methyl chloride cosolvents were analyzed using c urve-resolution software in conjunction with high-resolution g.p.c. Fractio nal precipitation and selective solvent extraction were applied to a repres entative sample in order to confirm the identity of contaminating species. The block copolymers were found to consist of 70-75 wt% of the target molec ule, and about 20 wt% of coupled (and higher Linked) block copolymers forme d by intermolecular electrophilic aromatic substitution linking reactions o ccurring during the styrene polymerization. Minor contaminants were identif ied as diblock copolymer and low molecular weight polystyrene homopolymer. (C) 1999 Elsevier Science Ltd. All rights reserved.