Preparation of block copolymers by use of peroxide-terminated prepolymer

Block copolymers containing poly(tetramethylene oxide) and poly(methyl methacrylate) segments were prepared. A commercially available poly(tetramethylene oxide) terminated with tolylene diisocyanate was capped with tert-butyl hydroxymethyl peroxide and the resulting prepolymer peroxide was used as a free-radical initiator of vinyl polymerization. Block copolymers formed in temperature-programmed vinyl polymerizations possessed improved impact strengths over poly(methyl methacrylate) from 0.35 to 1.18 for a fixed (nonoptimized) block length of poly(tetramethylene oxide).