Investigation of HTPB Based Composite Solid Propellant Aging by Van’t Hoff Method

In this article HTPB based composite solid propellant aging have been studied by Van’t Hoff method. Since composite solid propellants used in solid rocket motor is the fastest degrading component of the motor, shelf life of the motor is mainly governed by the propellants life. During handling and storage of rocket motor the mechanical properties of propellants are changing due to thermal, environmental, chemical, physical and internal changes. In this study the calculated F-factor was equal 2.5 by dynamic mechanical analysis on selected formulations of reference propellants sample. Then the accelerated aging program conditions have been determined. According to accelerated aging program the propellant samples subjected temperature range between 25°C and 80°C so that the aging time equal 2 years at 25°C. The evaluated of changes in the dynamic mechanical properties, including the storage modulus (E') and loss factor or damping efficiency (tanδ) to investigation of behaviour the composite solid propellant aging. The result showed that storage module increased with time whereas loss factor decreased. This phenomenon related to cross-linking density mechanism in polymeric binder system.