VARTM用环氧树脂固化动力学行为及力学性能分析

The Curing Kinetics and Mechanical Properties of Epoxy Resin for VARTM

为更准确地模拟VARTM工艺成形过程和分析固化变形,采用非等温DSC实验研究了2511-1A/BS环氧树脂体系的固化行为,使用T-β外推法确定了该环氧树脂体系的特征固化温度,并用Kissinger-Ozawa法计算得到了表观活化能。在此基础上,又分别建立了n级反应模型、自催化反应模型和两步反应模型,并进行了对比分析。结果表明,n级反应模型和自催化反应模型与实验的偏差较大,而两步反应模型的调整决定系数均大于0.99,更具有准确性。同时,为继续研究树脂在固化过程中力学性能的变化,采用DMA实验分析了树脂的动态热力学性能,并结合利用DiBenedetto公式得到的树脂玻璃化转变温度和固化度之间的关系,最终,建立了描述树脂模量变化的CHILE(T_(g))模型,模型预测结果与实验结果一致,证明具有较高的可靠性。

In order to simulate the VARTM process and analyze the curing deformation more accurately,the curing behavior of 2511-1 A/BS epoxy resin system was studied by means of non-isothermal DSC experiment.The characteristic curing temperature of the epoxy resin system was determined by T-βextrapolation method,and the apparent activation energy was calculated by Kissinger-Ozawa method.On this basis,the n-order reaction model,the autocatalytic reaction model and the two-step reaction model were established and compared.The results showed that the deviation of n-order reaction model and autocatalytic reaction model was large,but the adjustment decision coefficients of two-step reaction model were more than 0.99,which was more accurate.At the same time,in order to study the change of mechanical properties of the resin during curing,the dynamic thermodynamic properties of the resin were analyzed by DMA experiment.Combined with the relationship between the glass transition temperature and curing degree of the resin obtained by DiBenedetto formula,the CHILE(T_(g))model was established to describe the change of resin modulus finally.The predicted results were in good agreement with the experimental results,which proved its high reliability.