Isotactic polypropylene (iPP)-polystyrene (PS) and iPP-poly(methyl methacrylate) (PMMA) multiblock copolymers were synthesized by atom transfer radical coupling (ATRC) of PS-iPP-PS and PMMA-iPP-PMMA triblock copolymers obtained by atom transfer radical polymerization (ATRP) of styrene (St) and methyl methacrylate (MMA), respectively, using alpha,omega-dibromoisobutyrateoligopropylene (iPP-Br) as a bifunctional macroinitiator. The iPP-Br was prepared by hydroxylation and subsequent esterification of telechelic oligopropylene having terminal vinylidene double bonds at both ends obtained by controlled thermal degradation of iPP. ATRP of St and (meth) acrylic monomers using iPP-Br formed the corresponding triblock copolymers. It was confirmed that the PMMA-iPP-PMMA triblock copolymer was effective as the compatibilizer for the iPP/PMMA blend. An iPP-PS multiblock copolymer (M-n: 25 000 g/mol and M-w/M-n: 4.1) was prepared by ATRC of PS-iPP-PS triblock copolymer (M-n: 8900 g/mol and M-w/M-n: 1.3). ATRC with St of PMMA-iPP-PMMA triblock copolymer (M-n: 13 000 g/mol and M-w/M-n: 1.4) provided an iPP-PMMA multiblock copolymer containing St chains (M.: 39 000 g/mol and M-w/M-n: 2.8). (C) 2008 Elsevier Ltd. All rights reserved.