A review on viscoelastic behaviour of plasticizers in ap/al/htpb based composite solid propellant

Abstract

Solid composite rocket propellant is commonly employed in military applications, such as in a rocket missile fuel engine. However, ongoing research is still being conducted on the material composition, fabrication process, and design of the grain structure to modify the performance of rocket motors. One of the most important parts of studying the solid rocket propellant is the propellant grain's fabrication process, which is the rheology and viscoelastic behaviour of the plasticizer as an additive material in the propellant slurry. Recent research indicates that the flowability of the propellant slurry has a substantial effect on grain quality. The plasticizer is an additive material that can improve the flowability of the propellant slurry by elongating the polymer chain structure. On top of that, most researchers have proven that the most crucial behaviour of the plasticizers is the particle migration that will affect the homogeneity of the propellant composition. This unwanted phenomenon was proven by the experimental work using chromatographic and Shore A hardness analysis of the propellant layer. The plasticizer concentration at 1 cm from the insulation layer decreased from 3 % to 2.087 % after the propellant was cured and aged. The Shore A hardness test shows the lowest value was at 3 cm from the insulation layer compared to 25 cm. Besides, it was also found that Isodecyl Pelargonate (IDP) can be a potential plasticizer for AP/AI/HTPB-based composite solid propellant application because it has the lowest viscosity value in the propellant slurry compared to the others. Thus, this paper focuses on reviewing the rheological behaviour of the plasticizers, influence of the curing temperature, plasticizer concentration, and curing time of the AP/AI/HTPB solid propellant slurry because all these factors affect the viscosity value of the plasticizers in the propellant slurry.