Thermal Studies on the Saponification Products of Acryionitrile Terpolymer

Abstract

Thermal behavior of saponified products of an acrylic terpolymer was studied by differential scanning calorimetry and thermogravimetry in a nitrogen atmosphere. The exothermic reaction was attributed to the oligomerization of nitrile groups by comparing the extent of the reaction with the number of nitrile groups present. A shift in the position of the exotherm was observed with an increase in the degree of saponification up to 0.730, but further increase in the extent of saponification led to the disappearance of the exotherm though the nitrile content was found to range between 4.5 and 2.2%. The saponified products beyond a degree of saponification of 0.755 showed a broad endothermic peak instead of the exotherm. Thermo-gravimetric analysis of the products revealed that the exothermic reaction was concurrent with the weight loss. In the polyacrylo-nitrile homopolymer the threshold decomposition temperature was 248°C as compared to 294.8°C for acryionitrile terpolymer. The residue at 800°C was less for the terpolymer, and it further decreased with increasing extent of saponification.