基于主链型苯并噁嗪的新型低介电常数聚合物薄膜的分子设计、结构与性能

The development of organic polymeric thin films with low dielectric constant has been the requirement for realizing the miniaturization, high speed orientation, densification and low energy consumption of electronic devices. As long as the coming out of more and more polymers, benzoxazine has great potential to achieve this requirement due to its extraordinarily rich molecular design flexibility. In this submitted proposal, we incorporate the amide and alkynyl groups into benzoxazine moiety. Besides, the main-chain type benzoxazine with high molecular weight will be designed via click chemistry. The benzoxazole formation will be taken place after polymerization of benzoxazine, resulting the low polarity of the materials. Finally, the polymeric thin films containing benzoxazole group with low dielectric constant will be obtained. The dielectric constant of this materials is expected to be no more than 2. By adopting a systematical investigation of the synthesis, polymerization, and chemical structure evolution, the results will allow for addressing the formation mechanism and the relationship between the chemical structure and dielectric property, which services to lay an applied foundation of realizing dielectric tunable polymers via molecular design and to upgrade the developing industry of polymeric thin films with low dielectric constant.

开发低介电常数聚合物薄膜材料是实现电子器件微型化、高速化、密集化和低能耗化的迫切要求。随着新型高分子材料的不断问世，苯并噁嗪以其灵活多变的结构可控性为这一要求创造了条件。本项目从分子设计角度出发，合成兼具邻位酰胺与乙炔基团的苯并噁嗪单体，再结合点击化学方法，在苯并噁嗪单体基础上进一步制备高分子量的主链型苯并噁嗪。通过苯并噁嗪热固化反应产生邻羟基酰胺结构，再对邻羟基酰胺进行苯并噁唑热环化来减弱材料的极化度，最终制备出贯穿高刚性苯并噁唑基团的新型低介电常数聚合物薄膜材料，预期这种薄膜材料的介电常数不大于2。在深入研究苯并噁嗪合成、固化机理、聚合物结构衍变机制的基础上，阐明聚合物低介电常数的形成机制以及聚合物化学结构与介电性能的构效关系，为实现从化学结构调控聚合物介电性能奠定应用基础，为低介电常数聚合物材料行业的发展提供理论指导与实验依据。

从分子设计角度出发，合成系列苯并噁嗪单体与具有苯并噁嗪重复单元的主链型聚合物。通过苯并噁嗪热固化反应产生邻羟基酰胺基团，再通过进一步热处理对邻羟基酰胺结构进行苯并噁唑热环化来减弱材料的极化度，制备出系列贯穿高刚性苯并噁唑基团的新型低介电常数聚合物材料。为进一步提高聚合物热稳定性，我们在邻位酰胺苯并噁嗪中引入乙炔基基团，利用乙炔基与苯并噁嗪双重交联获得具有致密交联网络结构的热固性树脂材料；通过在苯并噁嗪单体中引入邻位三氟乙酰胺基团，利用温度调控该苯并噁嗪单体中分子内氢键的开/关，可实现该新型树脂的潜伏固化特性，在效降低苯并噁嗪的开环固化温度的同时确保树脂具有良好的可存储特性；通过含邻位酰胺基团重复单元结构的主链型苯并噁嗪的合成，通过苯并噁嗪环的开环固化与邻羟基酰胺的苯并噁唑热环化，可获得柔韧性优异的低介电聚合物薄膜材料，介电常数在1 MHz条件下可低于2.2。本项目在深入研究含酰胺基团苯并噁嗪的合成、固化机理、以及苯并噁唑热环化结构衍变机制，初步探索了实现聚合物低介电、耐高温等特性的实验方法，所制备的新型高性能苯并噁嗪树脂在航空航天、电子封装等高端领域具有良好的应用前景。