Degradation in mechanical and physical properties of carbon fiber/bismaleimide composite subjected to proton irradiation in a space environment

The aim of this article is to investigate the changes in mechanical and physical properties of a high performance carbon fiber/bismaleimide composite subjected to proton irradiation in a simulated space environment. The evolution of dynamic mechanical properties including storage modulus and damping parameter was studied by dynamic mechanical analysis. The variation of thermal stability was characterized by thermogravimetric analysis. The outgassing behavior was monitored by mass loss measurement. Changes in mechanical properties including flexural strength and interlaminar shear strength were measured. The results indicated that proton irradiation in high vacuum could decrease the storage modulus and the cross-linking of the composite, and induce reduced thermal stability and matrix outgassing. The flexural strength and the inter-laminar shear strength of the composites were reduced to a certain extent and then tended to level off with increasing fluence. Degradation in mechanical properties of the composite was mainly attributed to the surface chemical and physical erosion induced by proton irradiation.

► Proton irradiation caused a decrease in the storage modulus.
► The crosslinking degree of the composite was decreased.
► The thermal stability was reduced and then improved.
► The mass loss ratio reached a plateau value of 0.41%.
► The mechanical properties were reduced to some extent.