EFFECTS OF THERMAL AGING ON THE PROPERTIES AND LIFETIME PREDICTION OFHYDROXYL-TERMINATED POLYBUTADIENE

Thermal ageing of hydroxyl-terminated polybutadiene propellant binders was carried out at various temperatures between 50 and 100-degrees-C. The changes caused by this treatment in properties such as melt visco sity, functional end-groups, molecular weight, tensile strength, elast ic modulus and ultimate elongation were examined. The viscosity and av erage molecular weight increased with the ageing temperature and agein g period. A decrease in ultimate elongation and an increase in elastic modulus were observed. Tensile strength of the matrices prepared by c uring hydroxyl-terminated polybutadiene with isophorone diisocyanate d id not change. Lifetime for usability was predicted from the applicati on of the Arrhenius equation to be 7 years.