SYNTHESIS AND CHARACTERIZATION OF AMINOORGANOSILOXANE-BEARING POLYPHOSPHAZENES - NEW PROPERTIES BY THE ELIMINATION OF HYDROGEN-BONDING

The synthesis of new hybrid polyphosphazene-siloxane polymers is descr ibed. These polymers contain a polyphosphazene backbone and [(N-methyl amino)propyl]siloxane side groups, -N(Me)(CH2)(3)SiMe(2)OSiMe(3) or -N (Me)(CH2)(3)SiMe(2)OSiMe(2)OSiMe(3), in ratios of 1:1 and 1:3 with tri fluoroethoxy, 2-(2-methoxyethoxy)ethoxy, or p-methylphenoxy cosubstitu ents. The synthetic method utilized allows the polymer properties to b e tuned by variations in the cosubstituent ratios. The polymers were c haracterized by P-31, C-13, and H-1 NMR, differential scanning calorim etry (DSC), gel permeation chromatography (GPC), and elemental analysi s. The percent loading of siloxane-containing side groups and the natu re of the cosubstituents were correlated to the glass transition tempe ratures. The glass transition temperatures ranged from -83 to -22 degr ees C. The longer, trisiloxane-containing units generated lower glass transition temperatures than did the analogous polymers with disiloxan e-containing side groups. Several polymers were further characterized by dynamic mechanical analysis (DMA). In addition to glass transition temperatures, other transitions attributed to the siloxane side groups were detected at approximately -124 degrees C.