STYRENE POLYMERIZATION WITH A MACROINITIATOR HAVING SILOXANE UNITS

Block copolymers containing segments of poly(dimethylsiloxane) (PDMS) and polystyrene were synthesized. Dihydroxy terminated PDMS M(n) 2500 g/mol, was reacted with an aliphatic diisocyanate (isophorone diisocya nate) and an aliphatic hydroperoxide (t-butyl hydroperoxide). The resu lting polymeric peroxycarbamate having siloxane units (a new macroinit iator) was used as free radical initiator for vinyl polymerization of styrene. Formation of block copolymers was illustrated by several char acterization methods such as chemical and spectroscopic analysis, frac tionation, and GPC. Mechanical and thermal characterization of the cop olymers were made by stress-strain tests and DSC. The surface properti es and the morphology of the block copolymers were investigated by con tact angle measurements and SEM. (C) 1996 John Wiley & Sons, Inc.