Influence of rheological behaviour on extrusion parameters during non-continuous extrusion of multi-base propellants

During the production of multi-base propellants, in order to identify both the optimal and safety conditions to be used at processing these rubber-like compounds, its rheological behaviour is considered as a key factor. Thus, an analysis of their rheological moduli at the end of the mixing stage and prior to the non-continuous extrusion (ram extrusion) is required so as to predict the optimum parameters to be assumed for both the mixing and extrusion processes. The rheological analysis of this multi-base propellant is carried out by means of a DHR-1 rotational rheometer of TA Instruments, and the complex modulus is proposed as a generalized indicator of the rheological response of these special materials. The complex interrelations among the main parameters of the extrusion process (steady extrusion pressure and extrusion ram velocity) together with the rheological properties of these multi-base propellants, will serve to deduce useful technical guidelines for improving the manufacturing system productivity, safety processing conditions and final product quality.