THE PHASE STATE AND MECHANICAL-PROPERTIES POLY(BIS-TRIFLUOROETHOXYPHOSPHAZENE) CONTAINING DODECAFLUOROHEPTOXY GROUPS

The effect of introduction of up to 15 mol% of side 2,2,3,3,4,4,5,5,6, 6,7,7,-dodecafluoroheptoxy groups (OC7F12H3) into poly(bis-trifluoroet hoxyphosphazene) on the phase state and phase transition temperatures in the resulting copolymers was studied by methods of differential sca nning calorimetry (DSG) and X-ray diffraction. As the content of OC7F1 2H3 groups in the copolymers increases, the temperature of isotropizat ion decreases more rapidly than that of the crystal-mesophase transiti on, which leads to a decrease in the temperature domain of existence o f the mesophase. If the content of OC7F12H3 groups exceeds 8 mol%, the copolymers transform on heating immediately from crystalline into amo rphous state. The conditions of preparation and thermal. prehistory of the copolymer films have a very strong effect on their mechanical pro perties on uniaxial drawing.