Glass fiber reinforced plastic (GFRP) is used as support material for high energy physics and nuclear physics experiments due to its excellent thermal insulation and mechanical performance. High-energy physics and nuclear physics experiments produce large amounts of γ and neutron irradiation to the support material. In order to ensure the stability of GFRP under γ-irradiation conditions

the kinetic model of pyrolysis needs to be establish to calculate the activation energy under different irradiation doses. The obtained results show that the pyrolysis process of GFRP in a nitrogen atmosphere can be divided into three stages

the main mass loss stage occurs at 200-470℃. With the increase of radiation dose

the mass loss rate of GFRP increased. After 20

100 and 200 kGy γ irradiation

the mass loss rate of GFRP increased from 31.1% to 32.7%

35.5% and 37.5%

respectively

by 2%

3.9% and 4.4%. With the heating rate increased the mass loss rate increased significantly. After 200 kGy γ irradiation

the average activation energy of GFRP calculated by Friedman method was increased from 96.1 kJ·mol-1 to 116.6 kJ·mol-1

which increased by 21.3%. The average activation energy of GFRP calculated by FWO method was increased from 107.6 kJ·mol-1 to 125.4 kJ·mol-1

which increased by 16.5%. Microstructure analysis by SEM found that the binding degree of the glass fiber and the epoxy declines after γ irradiation

differential scanning calorimetry indicates that the curing reaction occur of epoxy in the irradiation process.