TOPOLOGICAL SAPONIFICATION OF ORIENTED POLY(VINYL TRIFLUOROACETATE) TO POLY(VINYL ALCOHOL) WITH GASEOUS AMMONIA

Drawn poly(vinyl trifluoroacetate) (PVTFA) films were converted into s yndiotacticity-rich poly(vinyl alcohol) (s-PVA) films through the sapo nification in solid state with gaseous ammonia. The intensities of cry stallization and racemic dad sensitive bands in infrared absorption sp ectra of the s-PVA films decreased with increasing heat-drawing ratio before saponification. In the s-PVA film prepared from the PVTFA heat drawn before saponification, the intensity of crystallization sensitiv e band did not change whereas that of racemic dad sensitive band decre ased with heating time respectively. This means that the solid s-PVA p repared from heat-drawn PVTFA has the solid structure determined by th at of PVTFA, i.e. the low degree of crystallization and high hydrogen bond content, The s-PVA has hot-water resistance and only soluble at t emperatures above 100 degrees C.