Determining service life and ageing characteristics of composite solid propellants by their chemical properties

Kösa, Yasemin
Solid composite propellants are widely used in rocket systems due to their extended manageability and practicality. Service life determination issue of these energetic materials is an extremely important subject as performance and operation safety of rockets may greatly be affected by ageing of propellant. In the literature, service life determination of composite propellants is commonly based on mechanical properties such as stress and strain parameters. In this study, direct monitoring of chemical alterations, such as change in soluble fraction and crosslink density, transpiring within the propellant is also included. Furthermore, building a model for these chemical properties in order to determine ageing characteristics and service life is aimed. Hence, to be able to offer an integral approach, mechanical and physical besides chemical properties of six different hydroxyl-terminated polybutadiene (HTPB) based propellants were observed within the scope of accelerated ageing process. Oxidative crosslinking was the primary ageing mechanism. As a result, stress at break and hardness values increased, whereas strain at break and soluble fraction values decreased during the course of accelerated ageing. Mechanical and chemical alterations were mathematically modeled using several different approaches. These results provide a basis for studies regarding service life determination of not only propellants, but also energetic and non-energetic polymeric materials.


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Citation Formats
Y. Kösa, “Determining service life and ageing characteristics of composite solid propellants by their chemical properties,” M.S. - Master of Science, Middle East Technical University, 2022.