Evaluation of the Mechanical and Temperature Cycling Capabilities of Solid Propellant and Binders Containing A Difunctional Hydrocarbon Prepolymer.

The fractionation of hydroxy terminated polybutadiene HTPB prepolymers has been completed. These prepolymers have difunctional contents of 64.5, 80, 85.5, 90, and 97. Infrared studies were made of the curing of HTPB using polyethylene films between salt plates. This method would be useful in detecting side reactions during cure. An infrared method was used to show that the antioxidant, Agerite White, reacts only very slowly with n-butyl isocyanate in benzene and should not interfere with the curing of these binders or propellants. Binder and propellant studies established a stoichiometric NCO to OH ratio of approximately 1.05 for these prepolymers. This value varies with each fractionated prepolymer and for this reason, much of the subsequent work was done at an NCO to OH ratio of 1.00. The propellant studies have shown conclusively that the prepolymers with very high difunctionality do not require a crosslinker to be cured. Author