Viscoelastic characterization of polymers for deployable composite booms

Deployable space structures are being built from thin-walled fiber-reinforced polymer composite materials due to their high specific strength, stiffness, and designed bistability. However, the inherent viscoelastic behavior of resin matrix can cause dimensional instability when is stored under strain. The extended time stowage between assembly deployment in result performance degradation worst case, mission failure. In this study, properties candidate commercial polymers consisting difunctional tetrafunctional epoxies thermoplastic thermosetting polyimides were evaluated for deployable boom solar sails. Stress relaxation master curves used predict that would occur 1 year at room temperature relatively low strains about 0.1%. A bismaleimide (BMI) showed less stress (about 20%) than baseline novolac epoxy 50%). Carbon fiber composites fabricated with BMI a 44% improvement resistance compared composite.