Investigation of the Effect of Gelling Agents on Dicyclopentadiene's Rheological Characteristics for Improvement of Composite Solid Propellant Quality

Abstract

Composite solid propellants utilizing polymerized dicyclopentadiene as a binder matrix have been shown to offer advantages in both strength and burning rate as compared to traditional binders. While these advantages are encouraging, advances in processing techniques for polymerized-dicyclopentadiene-based propellants are necessary before large-scale development can proceed. Dicyclopentadiene's low, water-like viscosity provides several advantages in mix/cast operations as these propellants are easily mixed, and can be poured into complicated casting hardware. Unfortunately, several disadvantages exist in using dicyclopentadiene. During the cure cycle, dicyclopentadiene's low viscosity allows the liquid binder to be wicked towards propellant surfaces and into casting hardware joints, measurable particle settling can occur, and a significant portion of the binder can evaporate off. These disadvantages combine to reduce propellant quality and produce an effective solids loading higher than intended. Another disadvantage occurs when formulations with large amounts of small-diameter particles are attempted. The small-diameter particles adsorb a higher portion of the binder than their larger counterparts, which can result in the mixing of dry components. To reduce the effects of these disadvantages, it was proposed that adding a gelling agent to the dicyclopentadiene binder would increase the binder's viscosity, making it better suited to particle suspension, and less prone to evaporation or wicking into casting hardware.