热处理对电子束辐射固化环氧树脂的作用效果

EFFECT OF HEAT TREATMENT ON EPOXY RESINS CURED BY ELECTRON BEAM RADIATION

通过对热处理前后电子束辐射固化环氧树脂的动态力学分析,研究了不同样品的凝胶含量、tanδ以及动态模量的变化规律.结果表明,对电子束辐射固化的环氧树脂进行热处理,可以提高样品的固化程度和玻璃化温度(Tg),热处理后样品的模量随着温度的升高而下降的幅度减少.随着辐射固化度的增加,热处理的影响减弱.当热处理温度超过辐射引发剂的热引发温度时,在样品的tanδ曲线上出现反应局部热交联网络的松弛峰.在辐射固化度相近的情况下,树脂体系中的引发剂含量和分子量对热处理的效果有重要影响.分子量分布多样性的环氧树脂体系在热处理后的固化程度、 Tg以及高温模量都较高.对于同样的环氧树脂体系,经过足够剂量的电子束辐射或进行适宜的热处理,所得固化物的Tg和高温模量均优于热固化样品.

The effects of heat treatment on electron beam (EB)-cured epoxy resin are studied in the paper. After heat treatment, the gel fraction in epoxy resin systems cured by EB radiation increase. The glass transition temperature (Tg) is shifted to a higher temperature and the E' keep at a high level with the increasing of temperature in the heat-treated samples. The a'-relaxation peak occurs in the tanδ curves of samples treated at 250 ℃ because the temperature of heat treatment is higher than the heat-initiating temperature of DPIPF6 initiator. When the curing density of radiation in samples increase, the effect of heat treatment is weakened and the position of the a'-relaxation peak gradually decreases. The content of initiator and molecular mass play an important role during heat treatment in the case of approximately same curing density of radiation exist in samples. The heat-treated samples with wider molecular mass distribution have the higher positions of Tg and thea'-relaxation peak. The curing density and E' at high temperature are higher in the heat-treated sample with high polydispersity.