Electrical/thermal stability of GFRP under different intensities γ ray irradiation

Abstract

• GFRPs were subjected to γ-irradiation with 0, 20, 100 and 200 kGy respectively. • The activation energy increases with the increasing intensity of γ-radiation. • The average resistivity increases with the increasing intensity of γ-radiation. Glass fiber reinforced plastic (GFRP) is used as support material in high energy physics and nuclear physics due to its excellent thermal insulation and mechanical performance, such as BEPCII, ITER and the CEPC Chinese government will build. But large amounts of γ and neutron irradiation were produced in these environments. The thermal decomposition kinetics and electrical insulation parameters of the material will be affected by the irradiation. In order to ensure the stability of GFRP under γ-irradiation conditions, the volume resistivity and the activation energy need to be calculated under different irradiation intensities. It revealed that γ-irradiation increases the electrical insulation of GFRP, and the insulation increases with increasing intensity. After 20 kGy, 100 kGy and 200 kGy γ-irradiation, the volume resistivity of GFRP increased from 8.16 × 10 12 Ω m to 15.88 × 10 12 Ω m, 23.13 × 10 12 Ω m and 43.15 × 10 12 Ω m, respectively. And the pyrolysis process of GFRP in a nitrogen atmosphere can be divided into three stages, the main weight loss stage occurs at 200∼470 ℃. Two methods were used to calculate the activation energy of GFRP under different irradiation intensities, and the results were compared. Irradiation improves the activation energy of GFRP. The microstructure of GFRP under different γ-irradiation intensities was studied by SEM and XPS. It was found that fragmentation tendency and pores appeared in the epoxy resin during the irradiation. GFRP was oxidized and the content of O1s increased with increasing intensity.