不同固化剂复配的耐高温环氧树脂体系性能

Properties of High Temperature Resistant Epoxy Resin Cured by Different Mixed Curing Agents

环氧树脂本身是一种热塑性树脂,只有加入固化剂,才能发生交联反应生成三维网状结构的热固性树脂,展现出优异的使用性能。因此,固化剂的选择和复配是决定环氧树脂使用性能的关键因素。4,4’-二氨基二苯砜(DDS)是一种应用较为广泛的高温固化剂,但其有着与环氧树脂混合后黏度较大、需要较高反应温度等缺点。文中选用了3,3’-二乙基-4,4’-二氨基二苯甲烷(DEDDM)、4,4’-二氨基二苯甲烷(DDM)、4-甲基1,3-环己二胺(HTDA)3种固化剂与DDS复配,通过非等温差示扫描量热分析研究了复配固化剂的含量和种类对反应活化能的影响;通过动态力学热分析和热重分析等测试研究了复配固化剂的含量和种类对固化产物热性能的影响。结果表明,复配固化剂DDM摩尔分数为20%时,复合体系的黏度在操作温度80℃时降低了70.4%,平均反应活化能降低了2.99 kJ/mol,玻璃化转变温度仍保持在219℃,符合耐高温树脂的使用要求。综合考虑各方面性能,体系20DDM可用作环氧树脂复合材料体系复配固化剂的首选。

Epoxy resin is a thermoplastic resin.It can show excellent performance only with adding curing agent to form three-dimensional network structure by cross-linking reaction.Therefore,the selection and combination of curing agent is the key factors to determine the performance of epoxy resin.4,4'-diaminodiphenyl sulfone(DDS)is a widely used high-temperature curing agent,but it has some shortcomings,such as high viscosity mixed with epoxy resin and high reaction temperature.In this paper,3,3'-diethyl-4,4'-diaminodiphenylmethane(DEDDM),4,4'-diaminodiphenylmethane(DDM),4-methyl-1,3-cyclohexanediamine(HTDA)were used to combined with DDS.Non-isothermal DSC was used to study the reaction activation energy of different contents and kinds of the mixed curing agents.The effects of the contents and kinds of the mixed curing agents on the thermal properties of the cured productss were studied by DMA and TGA.The results show that when the molar fraction of DDM is 20%,the viscosity is decreased by 70.4%at 80℃,the average reaction activation energy is decreased by 2.99 kJ/mol,and the glass transition temperature remains 219℃,which meet the requirements of high temperature resistant resin.Considering all aspects of properties,the system 20DDM can be used as the first choice of mixed curing agent for epoxy resin composites.