基于FBG应变监测的环氧树脂固化收缩及工艺参数优化

Curing shrinkage and process parameter optimization of epoxy resin based on FBG strain monitoring

采用布拉格光纤光栅(FBG)传感器,对一种典型液态成型环氧树脂在不同固化工艺以及后固化过程中的温度及应变进行了实时在线监测。通过将树脂内部应变变化转化为树脂线性体积变化,得到不同工艺过程中树脂的固化收缩规律,以此作为依据对树脂的经验固化及后固化工艺参数进行验证和优化。结果表明:所选液态成型树脂在80℃下固化,其固化度和玻璃化转变温度分别为90%和85℃,高于75℃固化树脂,但其总固化体积收缩只比75℃固化时略为增加了约5%;树脂在120℃下进行后固化处理时,恒温180min后FBG传感器监测到的树脂内部应变已不再变化,此时树脂已基本完全固化,无需再延长后固化时间。

Temperature and strain in a representative liquid molding epoxy resin were in-situ monitored by Fiber Bragg Grating（FBG）sensors throughout different curing processes and post-curing processes.Curing shrinkage regularity of the resin in different processes was derived from its linear volume variation transformed from the strain evolution in resin.Process parameters of experiential curing and post-curing processes were validated and optimized based on the curing shrinkage.The results show that conversion degree and glass transition temperature of the liquid moldingresin cured at 80 ℃ are 90% and 85 ℃respectively,which are higher than resin cured at 75 ℃.However,total curing shrinkage of the resin cured at 80℃is only 5% higher than cured at 75℃.The strain in resin becomes constant after 180 min in isothermal procedure of 120 ℃ post-curing,which means the resin is cured completely.There is no need to extend the post-curing time.