SYNTHESIS OF THE MODEL MACROINITIATORS OF FREE-RADICAL POLYMERIZATIONAND THEIR APPLICATION FOR THE PREPARATION OF BLOCK-COPOLYMERS

A series of polystyrenes having low molecular weight (4600-23,100) and narrow molecular weight distribution and functionalized with a benzop henone group at one or both ends of the chain have been prepared throu gh anionic polymerization. Then the terminal benzophenone groups have been transformed into 1,2-bis(trimethylsilyloxy)tetraphenylethane (or benzopinacolate) groups by the duplication reaction with free benzophe none in the presence of chlorotrimethylsilane and hexamethylphosphorou s triamide (HMPT) or hexamethylphosphoramide (HMPA), producing model t hermal macroinitiators of free radical polymerization with well-define d structure. Polymerization of MMA initiated by these macroinitiators was carried out yielding poly(styrene-b-methyl-methacrylate) (PS-b-PMM A). (C) 1996 John Wiley & Sons, Inc.