SYNTHESIS OF POLYPHOSPHAZENE BLOCK-COPOLYMERS BEARING ALKOXYETHOXY AND TRIFLUOROETHOXY GROUPS

Block copolymers were formed by the anionically initiated copolymeriza tion of (CH3OCH2CH2O)(CF3CH2O)2P=NSi(CH3)3 or (CH3OCH2CH2OCH2CH2O)(CF3 CH2O)2P=NSi(CH3)3, followed by the subsequent addition of(CF3CH2O)P=NS i(CH3)3. These materials were characterized by P-31 and H-1 NMR, SEC, and DSC. SEC traces show that these block copolymers exhibit monomodal molecular weight distributions. In addition, there is a gradient in t hermal and mechanical properties which is dependent upon the repeating unit ratios. The properties are also different from those of the anal ogous random copolymers.