双酚A型环氧树脂的1.5MeV电子束辐照效应

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

本工作以双酚A型环氧树脂为研究对象,在1.5 MeV电子加速器下分别以18 kGy/h和2250 kGy/h的剂量率对其进行辐照处理,以达到总吸收剂量135 kGy、270 kGy、500 kGy和1000 kGy。系统研究了两种不同剂量率和不同吸收剂量对环氧树脂表面形貌、化学结构和热性能的影响。结果表明:电子束辐照环氧树脂时,高剂量率下环氧树脂内部会产生脉状裂纹,而总吸收剂量对树脂的热稳定性和力学性能影响较大;环氧树脂经电子束辐照后,玻璃化转变温度和交联密度下降,同时力学性能下降,表明辐射裂解占主导;电子顺磁共振光谱测试表明辐照过程中有烷基自由基和过氧自由基的产生,自由基浓度与吸收剂量呈正相关性。进一步研究了自由基在空气中的稳定性,随着存放时间的增加,自由基浓度最终趋于稳定。

Bisphenol A epoxy resin was irradiated in air by a 1.5 MeV electron beam accelerator at dose rates of 18 kGy/h and 2250 kGy/h to achieve the total absorbed doses of 135 kGy,270 kGy,500 kGy,and 1000 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.