Effect of cross-linking bonding agent on the ballistic characteristics of composite solid rocket propellant at high operating pressure

Abstract The novel cross-linking bonding agent, designated as MSC, was meticulously synthesized and subsequently incorporated into the existing bonding agent matrix with the primary objective of significantly enhancing the mechanical properties of composite propellant. This enhancement is achieved by improving the interfacial interactions between the bonding agent and the solid particles, which are crucial for withstanding the various stresses that are produced as a result of combustion loading conditions, as well as fluctuations in environmental conditions, transportation, and handling, all without adversely affecting the ballistic performance of the propellant. In the course of this research endeavour, the substitution of the cross-linking MSC bonding agent for the widely recognized reference bonding agent MAPO has resulted in a notable improvement in the mechanical properties, particularly concerning the strain values that correlate with the stress values. This substitution has effectively doubled the maximum strain value while still maintaining an acceptable maximum stress value, along with a commendable value for Young's modulus within the various propellant formulations being considered. A range of different compositions of composite propellant was systematically investigated in order to accurately measure the linear burning rate and to thoroughly study the effects brought about by the replacement of the MSC bonding agent in lieu of the traditional bonding agent MAPO. The presence of the bonding agent is expected to facilitate a more regular and stable burning process of the composite propellant, particularly under conditions of high dynamic pressure, thereby contributing to more predictable combustion characteristics. Furthermore, various nozzle diameters were employed, each providing distinct burning rates and pressures, thereby enabling the determination of the pressure exponent and the burning rate constant through systematic experimentation and analysis.