基于非等温DSC方法对干式变压器浇注用环氧树脂体系动态升温过程中的固化动力学进行了研究,采用无模型法得到了体系的活化能和指前因子与固化度之间的关系,发现该体系的固化反应不是简单的一步反应,而是复杂的多步反应.用唯象模型拟合法对DSC测试结果进行了非线性拟合,两者吻合很好,相关度达99.51%,表明该体系符合通用n级三步分支反应模型.最后用唯象模型对该体系的等温反应进行了预测,结果显示,相同固化时间下,固化温度越低,体系的固化度和固化速率也越低.

The cure kinetics of dynamic heating process of epoxy resin system used for casting dry-type transformer is investigated based on the nonisothermal DSC method,and the relationship between the curing degree and the preexponential factor as well as the activation energy is revealed by using the free model method.The results show that the curing of epoxy resin system is not a simple one-step reaction but a complex multi-step one.Then,the DSC data are nonlinearly fitted via the phenomenological model.The fitting results accord well with the experimental ones with a correlation of 99.51%,which means that the system complies with the n-level three-step branch reaction model.Finally,isothermal prediction for the system is performed by using the established phenomenological model.The results show that,at constant curing time,the curing degree and rate both decrease with the curing temperature.