Thermal decomposition studies on copolyurethanes based on hydroxyl terminated polybutadiene and poly(12-hydroxy stearic acid-co-TMP) ester polyol

Thermal degradation of copolyurethanes based on hydroxyl terminated polybut adiene (HTPB) and poly(12-hydroxy stearic acid-co-TMP) ester polyol (PEP) w ith varying compositions has been studied by thermo-gravimetric and pyrolys is-GC techniques. The copolyurethanes were found to decompose in multiple s tages and the kinetic parameters were found to be dependent on the method o f their evaluation. The activation energy for the initial stage of decompos ition was found to increase, and for the main stage decreases with the incr ease in PEP content. The pyrolysis-GC studies on the ammonium perchlorate f illed copolyurethanes (solid propellants) showed that the major products du ring the pyrolysis were C-2, C-3 hydrocarbons and butadiene. The amount of C-2 fraction in the pyrolyslate increased with solid loading, as well as wi th the HTPB content in the copolyurethanes. A linear relationship apparentl y exists between the amount of C-2 fraction and the burn rates of the solid propellants. (C) 2000 Elsevier Science Ltd. All rights reserved.