Block Copolymers from Organomodified Siloxane‐Containing Macroinitiators by Atom Transfer Radical Polymerization

Alternating copolymers of 1,3-diisopropenyl-benzene and 1,1,3,3-tetramethyldisiloxane were synthesized by hydrosilylation-polyaddition. These linear copolymers were functionalized at both ends with 2-bromoisobutyryl or benzeyl chloride moieties. Subsequently, the obtained organo-modified siloxane-containing macroinitiators were sucessfully used for the preparation of ABA-type block copolymers by atom transfer radical polymerization (ATRP) of styrene and tert-butyl acrylate. The high chain-end functionality of the macroinitiators was confirmed by 1 H NMR analysis of the macroinitiators and GPC measurements of the obtained ABA-type block copolymers. The macroinitiator peaks disappeared in GPC traces after ATRP, and the obtained block copolymers showed a significantly narrower molecular-weight distribution than the macroinitiators.