Synthesis and characterization of poly(dimethyl siloxane) containing poly(vinyl pyrrolidinone) block copolymers

ABA-type block copolymers containing segments of poly(dimethyl siloxane) an d poly(vinyl pyrrolidinone) were synthesized. Dihydroxyl-terminated poly(di methyl siloxane) was reacted with isophorone diisocyanate and then with t-b utyl hydroperoxide to obtain macroinitiators having siloxane units. The per oxidic diradical macroinitiators were used to polymerize vinyl pyrrolidinon e monomer to synthesize ABA-type block copolymers. By use of physicochemica l methods, the structure was confirmed, and its characterization was accomp lished. Mechanical and thermal characterizations of copolymers were made by stress-strain tests and differential scanning calorimetric measurements. ( C) 1999 John Wiley & Sons, Inc.