电绝缘纳米复合材料的微结构设计及其对导热、介电性能的调控研究

With the rapid development of microelectronic integration technology, at the same time of implementation electronics multi-function miniaturization, how to effectively improve the heat dissipation problem of electronic packaging materials has become the common focus primary problem that the current world industry and academia must resolve. Aiming at this problem, here the applicant will propose three aspects new microstructures research based on his original work: one is that, high thermal conductivity materials are chosen as the core of core-shell structure, and another is that low dielectric constant materials are chosen as the shell, to prepare fillers with the core of high thermal conductivity and the shell of low dielectric constant of the multi-layer core-shell structure, and then the fillers are modified with a polymer by chemical methods with the purpose of effectively improving the dispersion of filler in polymer matrix, reducing the contents of porosity and defects, etc., which in order to improve the thermal conductivity of the composite. Designing novel composite structures to build effective heat conduction network, accelerate the heat transfer in the composites, and effectively improve thermal conductivity of composite materials. The proposed will be more conducive to solve the thermal transmission problem of electronic packaging composite, explore the relationship between the structure and performance of composite materials and the phase interface effect, as well as it forward a new study way for polymer-based composite filler modification and the improvement of thermal management performance.

随着科技的迅猛发展，在实现电子器件多功能小型化的同时，如何有效地提高电绝缘材料的散热问题已成为当前全球工业界和学术界共同关注和亟需解决的首要问题。本项目提出从复合微结构的设计角度出发，通过结构与功能一体化设计，研制兼具高导热、低介电且绝缘性良好的聚合物基纳米复合材料，实现材料微结构对性能的调控，从而获得最佳的综合性能。本项目设计的微结构如下：1.MWCNT-纤维素水凝胶纳米填料三维网络结构；2.石墨烯-类“三明治”结构；3.银系螺旋-粒子微结构等，采用高导热填料的表面改性和设计微结构等方法来解决复合材料热导率低、电学性能不理想的难题，通过组建有效的三维导通网络以期望获得较高的热导率，较低的介电常数和优良电绝缘性能的纳米复合材料。深入探讨复合材料的微结构与性能之间的关系，揭示复合材料中的多相界面效应作用机理，为聚合物基电绝缘复合材料的填料改性处理和热管理性能的提高提供新的研究思路。

本项目源于电气领域电子元器件的“散热”问题，属于目前世界科技前沿的研究热点，已成为国家工业和经济发展亟待解决的重要难题。本项目提出采用填料的表面改性和设计新复合微结构等方案来尝试解决复合材料热导率低、电学性能不理想的难题，通过组建有效的三维导通网络以期望获得较高的热导率，较低的介电常数和优良电绝缘性能的纳米复合材料，优化复合材料的制备工艺，降低界面效应对复合材料的影响，找出最佳的平衡点，使电绝缘复合材料同时满足高绝缘、高导热和低介电等性能。具体完成了以氮化硼(BN)、聚多巴胺(PDA)及纳米银(Ag)等三种材料对高导热材料:铜纳米粒子(CuNPs)、铜纳米纤维(CuNWs)、石墨片(GNS)及多壁碳纳米管(MWCNTs)等进行表面改性处理的制备方法，制备出具有三维网络结构的高导热电绝缘复合材料。结果表明，在质量填充比为10%时，(CuNPs-CuNWs)@BN/PI复合材料的热导率为4.32W/mK，是纯PI的24.1倍；而此填充比下1MHz时复合材料的介电常数和介电损耗分别为4.92和0.026，以聚合物PVA为基体制备(GNS-MWCNT)@AgNPs/PVA复合材料，获得了12.3W/mK较高的热导率，是纯PVA热导率的69.1倍，本项目制备出的复合材料基本满足微电子封装用高导热、低介电性能的需求。此外，还进一步分析和探讨了三维网络结构的制备原理以及结构对复合材料性能的影响，本项目的顺利实施为聚合物基电绝缘复合材料的填料改性处理和热管理性能的提高提供新的研究思路。