环氧树脂与氰酸酯共固化物的结构与性能

Structure and property of co-curing reaction product for epoxy and cyanate resin system

研究了用乙酰丙酮过渡金属络合物等促进剂催化促进环氧树脂与氰酸酯(在氰酸酯欠量,适量和过量条件下)的共固化反应行为、固化反应的机理、固化物的结构特征以及结构与性能关系.结果表明,促进剂能明显地降低体系的固化反应温度,缩短固化反应时间,其促进效果与促进剂种类有关.在固化反应过程中,先是氰酸酯发生自聚反应形成二聚体或三聚体(三嗪环),然后二聚体进一步形成三嗪环,此过程伴随着环氧树脂的聚醚反应,最后是三嗪环与剩余的环氧基反应形成嚼唑烷酮.在氰酸酯欠量的条件下,固化物的交联结构主要是聚醚网络结构和(?)唑烷酮结构,三嗪结构很少.在氰酸酯适量和过量条件下,固化物交联结构主要是三嗪环和(?)唑烷酮结构,聚醚结构很少.随着氰酸酯含量的增加,三嗪结构随之增加,聚醚结构减少,固化物的耐热性能和介电性能随之提高.

The behavior, mechanism, product structure and relation of structure with properties for co-curing reaction of epoxy resin and cyanate ester system catalyzed by transition metal acetylacetone were studied. The results show that the accelerator can obviously accelerate the co-curing reaction of the resin system and decrease the cured temperature and curing time. The reactions involved in the co-curing are: cyclodimerization and cyclotrimerization of cyanate, polyetherification of epoxy group and cyclotrimerization of cyclic dimmer, as well as the formation of oxazolidone rings. In the lack of cyanate functional groups, the main structures of cured compounds are oxazolidone and polyether structure in the cured resin, and the triazine ring structure is of minor importance. In the excess of cyanate functional groups, the main structures are triazine ring and oxazolidone structure in the cured resin, and the polyether structure is of minor importance. The reactive activation energy and frequency factor of the co-curing resin system increase with enhanced concentration of cyanate. The thermal stability and dielectric properties of the cyanate and epoxy resin curing system are also found to increase with enhanced concentrations of cyanate in the same cured condition.