Effects of γ irradiation on the structure, physical and mechanical properties of a series of tetrafunctional epoxies modified DGEBA/DDS

Abstract In some nuclear applications, epoxy materials have become increasingly appealing. However, radiation-induced structural changes often deteriorate properties. Thus, the long-term stability of epoxies after exposure to radiation has to be evaluated. Irradiation induced changes in three tetrafunctional epoxy modified DGEBA/DDS were reported. Irradiation leads to changes in chemical structure and appearance, i.e., darkening in color and reduction in transparency. Irradiated samples show two absorption centers, and both the bending and tensile strengths of samples, which are modified by the tetrafunctional epoxy that has a diphenylsulfone spacer, maintain high values even after 2.8 MGy irradiation. γirradiation leads to chain scission and decreases Tg; however, Tgs of irradiated samples modified with tetrafunctional epoxies were still higher than 220 °C. Results show that addition of tetrafunctional epoxies improves Tg of DGEBA/DDS after exposure to radiation. Irradiation-induced chain scissions also increase the heterogeneity of the cured network. Although γray reduces the thermal stability, the thermal and mechanical properties are adequate for many applications.