Effect of propellant components on degradation of polyether-urethane binder (I) the effect of nitrate esters

The effect of two nitrate esters (NG, BTTN) on the degradation of EO/THF copolyether-urethane binder was studied by structural analysis of degradation products with FT-IR and NMR methods. Alcohols were the main degradation products of these two nitrate esters. Structural confirmation proved that these alcohols were mainly generated from the hydrolysis of nitrate esters and subsequently underwent the repolymerization with isocyanates to form carbamates. It was also surprisingly found that nitrate esters showed some stabilizing effect on the polyurethane binder but resulted in high proportion of formates and tertiary carbons in the degradation products of polyurethane and that no efficient absorption of nitric free radicals by centralite I was found on the current experimental condition. To ecplain these observations, a mechanism was suggested that the nitric free radicals derived from the decomposition of nitrate esters reacted with peroxides to form nitric acid, which accelerated the hydrolysis of nitrate esters.