Classification of Solid Propellants
There are two types of solid propellants:
• Homogeneous solid propellants
• Composite solid propellants
Homogeneous solid propellants are of two types:
• Simple base homogeneous solid propellants
• Double base homogeneous solid propellants
Simple base propellants are those propellants which consist of only one compound having both oxidation and reduction properties. This compound is usually nitrocellulose.
Double base propellants consists of two compounds, usually nitrocellulose and nitroglycerine, along with a plasticizer (added to impart flexibility). The advantage of this type of propellant is that it does not produce smoke. Thus increases energy and burning rate.
Composite propellants are heterogeneous mixtures. These use crystallized or finely ground mineral salt as oxidizer. This oxidizer forms the bulk of the propellant. The fuel used is aluminum. A polymeric binder holds the propellant together. Sometimes catalyst is added to improve burning.