含氮杂环结构的阻燃环氧树脂基电子材料

Epoxy-Based Electronic Materials Containing Nitrogen Heterocyclic Ring: Flame Retardancy

"无卤无磷无铅"的绿色阻燃环氧树脂基电子材料是既能满足阻燃功能、又需符合环保要求的热固性(复合)材料,是目前阻燃热固性树脂领域的重点和难点课题。有机氮杂环作为一类高效、低毒的阻燃结构,可以共价引入至环氧树脂中,但至今还未建立系统的氮杂环的结构与其阻燃性能的关系。本文结合本课题组近十年的研究工作,综述了近年来国内外含氮杂环阻燃环氧树脂的研究进展,讨论了不同含氮杂环结构(三嗪环、异氰脲酸酯环、二氮杂萘酮、酰亚胺、苯并嗪和海因环等)环氧树脂固化物的制备方法,给出了定量的结构与性能关系。利用共价键法将含氮杂环结构引入环氧树脂体系中,在实现阻燃功能的同时也能保持材料的综合性能,甚至可提高环氧树脂固化物的热稳定性能,因而制备含氮杂环结构的环氧树脂是"无卤无磷无铅"绿色阻燃的重要解决方案。但是,目前仅依靠含氮杂环结构很难达到理想阻燃效果,大部分已报道的体系只能达到"无卤无铅少磷"的水平,仍需要进一步深入研究和认识含氮杂环结构的阻燃环氧体系的结构-性能关系,并提出提高含氮杂环体系阻燃效果可能的解决方法。

Halogen-, phosphorous- and lead-free flame-retardant epoxy-based thermosets are environmental- friendly materials and expected to be applied to the electronic materials. Nitrogen heterocyclic ring is highly efficient flame-retardant with low toxicity and has been covalently introduced into the backbone of the epoxy polymers, but so far the structure of such nitrogen heterocyclic ring and its flame-retardant property for epoxy resin has not yet closely correlated. Based on our previous works in the field, this article summarizes recent research progress for synthesis and application of the flame retarded epoxy-based thermosets containing nitrogen heterocyclic ring, including triazine, isocyanurate, azo phthalazinone, imide, benzoxazine and hydantion rings, etc. The structure-property relationships of these systems are presented in detail. Generally, introducing nitrogen heterocyclic structures into epoxy resin systems by covalent bonding can maintain the overall performance whileendow the flame retardancy to the final materials. Moreover, nitrogen heterocyclic structure can improve the thermal stability of the cured epoxy resins. As a result, epoxy resin containing nitrogen heterocyclic structures might be a good choice to obtain halogen-, phosphorous- and lead-free flame retardant epoxy-based electronic materials. However, it is still a big challenge to get flame-retardant epoxy-based thermosets just depending on nitrogen heterocyclic structure in these materials. Most of the reported systems had contained low content of phosphorous for bettering the flame retardancy. As a result, it is important to intensively understand the structure- property relationship of nitrogen heterocyclic ring-containing epoxy resin. Several methods are proposed for improving the flame retardancy of nitrogen heterocyclic ring-containing epoxy resin.