| Abstract: | Solid propellant rocket technology makes use of polyurethane propellant system based on hydroxy terminated polybutadiene as binder. Processability of the propellant is determined by viscosity build-up after unloading from the mixer, which in turn depends on rate of curing reaction between alcohols and isocyanate. For a typical binder system consisting of alcohols and isocyanate as in propellant composition, rate of curing has been studied using IR spectroscopy are carried out in solution phase. In this study, unaltered binder system was studied as such for the progress of the reaction as a function of time. Concurrently, viscosity studies were also carried out to study the rate of viscosity build-up with time as reaction proceeds. With these studies two distinct phases have been brought out for the cure reaction of binder, first phase involving a linear reduction in concentration of the isocyanate groups followed by the second phase tending to equilibrium. |
