Research on the Aging Properties of HTPB Propellant under Vacuum

Abstract

The space environment has high vacuum, rapid temperature alternations and other extreme conditions, which can affect the energy, ignition rate and ignition performance of solid propellants in the space environment. In order to obtain the space aging performance of HTPB propellant, this paper investigates the aging performance of HTPB propellant in vacuum environment and compares it with atmospheric pressure, and analyses the oxidative cross-linking, degradation chain scission and “dehumidification” behaviour based on the mechanical properties, cross-sectional state and infrared spectra of propellant before and after aging. The research results show that the anhydrous environment under vacuum prevents the occurrence of the chain scission degradation of HTPB propellant, and HTPB propellant is basically only affected by the oxidative cross-linking reaction, where the reaction rate is slow. The mechanical properties show that the breaking strength increases slightly in the first stage, in the later stage of aging, the oxidative cross-linking reaction was intensified due to the decomposition of AP, and the breaking strength increased obviously compared with the initial value. Under the atmosphere, the HTPB propellant was mainly affected by oxidative cross-linking reaction in the early stage of aging, and the breaking strength increased. In the later stage of aging, due to the chain scission degradation of OA moisture absorption, the breaking strength showed an opposite trend and decreased. In addition, an obvious “dehumidification” phenomenon occurs inside the propellant after aging, which is more obvious under a vacuum.