Studies on Interface Properties of Propellant Liner for Case-Bonded Composite Propellants

For ensuring a good bond between the insulator and the propellant, a thin layer of liner is applied. Liner compositions should preferably be based on the same binder system used in the propellant formulations. As the liner is to hold the propellant and insulator without debond in all the environmental conditions, the interface properties are very important. Studies were carried out on the effect of particle size of ammonium perchlorate (AP) and the R value on the interface properties. It was found that interface properties highly depend upon the particle size of AP and the coarse-fine ratio of AP in the propellant formulation. As the percentage of fine AP increases, peel value decreases. Liner compositions are developed with aziridine-based compounds to improve the interface properties for compositions containing a large amount of very fine AP. Aging properties of the interface bonding have also been undertaken.