Radiation effects of a 1.5 MeV electron beam on bisphenol A epoxy resin

Abstract

Bisphenol A epoxy resin was irradiated in air by a 1.5 MeV electron beam accelerator at dose rates of 18 kGy/h and 2 250 kGy/h to achieve the total absorbed doses of 135 kGy, 270 kGy, 500 kGy, and 1 000 kGy. The effects of the dose rates and the absorbed doses on the surface morphology, chemical structure, and thermal properties of the epoxy resin were systematically investigated. The results showed that high dose rates induced vein-like cracks in the epoxy resin, while the total absorbed dose significantly affected the thermal stability and mechanical properties of the resin. Moreover, the epoxy resin exhibited a radiation cross-linking tendency at low absorbed doses, while radiation degradation dominated at high doses. An electron spin resonance analysis indicated that the free radical signals generated during the irradiation were from alkyl radicals and peroxy radicals. The concentration of free radicals was positively correlated with the absorbed dose. Furthermore, the stability of the free radicals in air was studied. The concentration of the generated free radicals reached a plateau at longer storage times.

Keywords

• bisphenol a epoxy resin
• electron beam irradiation
• mechanical properties
• free radicals