Studying the Effect of Microstructure of Hydroxyl Terminated Polybutadiene (HTPB) on the Mechanical Properties of HTPB-based Propellant

The mechanical properties of the final energetic composite depend mainly on the HTPB prepolymer microstructure; thus, the prepolymer microstructure of HTPB is one of the important factors influencing the mechanical properties of highenergy composite based on HTPB resin. In this paper, the effect of microstructure parameters of HTPB on the behavior and mechanical properties of its high-energy composite has been investigated. The difference in the production of these polymers, as well as their variability, leads to the formation of various polymers in the microstructure parameters of HTPB (molecular weight distribution and factor distribution). These differences often affect the processability, lifetime of the appliance, the behavior of cooking, and especially the mechanical properties of high-energy composites. Using various grades of HTPB has various microstructural parameters, in order to achieve the optimal mechanical properties with high bar resistance according to the results, there is a need to understand the microstructure of the binder, namely, prepolymer. The studies carried out in this paper show that with increasing molecular weight of HTPB, tensile strength, modulus, rupture resistance and hardness decrease, and by decreasing the high molecular weight component of HTPB, the exponential and high-energy composite modulus increases. There is a linear relationship between the amount of hydroxyl and the mechanical properties of the tensile strength and modulus.