环氧树脂/氰酸酯共固化体系热性能的研究

通过凝胶实验和DSC测试，研究了含异辛酸钴促进剂的环氧树脂(EP)/氰酸酯(CE)共混体系中的工艺参数对固化速度和产物热性能的影响。结果表明，当固化温度高于180℃时，加入促进剂的量高于0.05%对体系的固化反应速度无明显的影响。综合考虑体系的热性能、成本、可加工性等因素，该体系最佳的工艺和配方为m_EP/m_CE为6/4，w_钴盐=0.05%，T_固化=180℃，t_固化=3h，在200℃下后固化2h。在所选出的这种配方和工艺条件下得到的样品的热变形温度可达201℃。DSC和红外光谱的分析结果还表明，固化反应分为2步，首先为氰酸酯的自聚生成三嗪环，再与环氧基团反应生成噁唑啉及噁唑烷酮结构。这些生成的五元和六元环使体系的热性能明显提高。

Study of the thermal properties of the epoxy resin/cyanate ester co-curing system

By means of gelation and differential scanning calorimetry (DSC) experiments, the effects of varying the reaction parameters on the speed of the curing reaction and the thermal properties of the resulting products were investigated for the epoxy resin/cyanate ester system catalyzed by cobalt isootanoate. It was found that the optimum content of the catalyst was 0.05% if the resin was cured at above 180℃. By consideration of key factors including thermal properties, cost, and processability, the most effective conditions were found to be m(epoxy resin)/m(cyanate ester)=6/4，w(cobalt isootanoate)=0.05%, cured at 180℃ for 3h, and then post cured at 200℃ for 2h. The thermal distortion temperature of a sample prepared under these conditions was as high as 201℃. In addition, it was suggested by Fourier transform infrared spectroscopy and DSC that the curing reaction is composed of two steps. The first step involves the trimerization of the cyanate ester monomer, forming triazine rings, which subsequently react with the epoxy resin forming oxazolidone and oxazoline. It is suggested that the improved thermal properties of the products may be related to the presence of these multi-ring structures.