Study on the Rheological Properties of Fuel Rich Composite Solid Propellants Based on HTPB

Composite solid propellants based on Hydroxyl-terminated polybutadiene (HTPB) are commonly used in solid rocket motors (SRM) in defence and space applications. The solid propellant is a polymeric matrix with high solid loadings of metal fuel and oxidiser along with some additives. Each of the metal powders can affect the rheological properties of the propellant due to their special and unique properties, type of granulation, type of particle size, and morphology. The investigation of the rheological properties of three types of metal fuel, aluminum, magnesium and boron, which are the most used as solid metal load in the propellants, was done in this article. The results showed that the rheological properties depend significantly on the physical and chemical interactions between the fillers and the matrix. Changes in the shape, size of particles and the percentage of addition of metal solid loading have a great effect on the viscosity and yield stress of the propellant. Due to the heat of combustion and higher density aluminum has a better effect on rheological properties than the other two metals, but magnesium shows a better effect on combustion properties and it is often referred to as combustion additives. The combination of boron metal powder with magnesium or aluminum powder can greatly improve the rheological and combustion properties of fuel rich propellants.

Keywords:

Composite Solid Propellant , Fuel Rich Propellant , Highly Filled Composite , Rheological Properties