Investigation of HTPB Microstructure Effects on the Aging of Composite Solid Propellant Using Dynamical Mechanical Analysis

In this article aging behavior of composite solid propellant was investigated by determining its mechanical properties at elevated temperatures. For this purpose, three HTPB samples with different microstructures were selected and composite solid propellants were prepared based on them keeping similar other components and aging was studied by accelerated method. Mechanical properties were measured after accelerated aging using dynamic mechanical thermal analysis (DMTA) in order to investigate the effect of HTPB microstructure on composite solid propellant aging. Results showed that with increasing molecular weight, hydroxyl value, increasing vinyl and decreasing cis contents in resin microstructure, the mechanical behavior of the propellant becomes more rigid, which may be due to limiting the polymer chain mobility or facilitating post-curing crosslinking. Over aging time, the shelf life changed effectively with propellant binder microstructure. The obtained shelf life for the composite solid propellants based on D01, D02 and D03 resin samples were 6, 4.48 and 3.56 years. The results showed significant differences and show well the affect of the micro-structural properties of HTPB resin on the aging of its-based composite solid propellant.