耐高温、高导热聚合物复合绝缘材料的原位聚合制备和介电、热学性能研究

Dissipating the heat from the electrical equipment and electronic devices is important to improve their performance, to increase their reliability and to prolong their lifetime. The traditional polymer insulating materials have low thermal conductivities and thus are the bottleneck of the heat-dissipation in the electrical equipment and electronic devices. The good way to resolve this problem is to develop electrically insulating but thermally conductive polymer composites with high thermal durability and processability. In this project, by using surface-modified boron nitride nanotubes (nanospheres) as fillers and using the surface-initiated in situ polymerization technique (i.e., introducing the precursors of polyphenylene sulfide onto the surface of boron nitride nanoparticles), we plan to prepare electrically insulating but thermally conductive polyphenylene sulfide/boron nitride composites with high thermal durability and processability. We plan to control the ratio of polyphenylene sulfide to boron nitride in the composites and to control the chain length, the degree of branching and the state of aggregation of polyphenylene sulfide. We will perform the comparative study on the dielectric and thermal properties of the polyphenylene sulfide/boron nitride composites prepared by in situ polymerization technique and the traditional compounding methods. The final aim of this project is to reveal the structure-property relationship of the polyphenylene sulfide/boron nitride composites. The results of this research will provide theoretical knowledge and experimental guide to develop electrically insulating but thermally conductive polymer composite with high thermal durability and processability.

为了提升电力设备和电子器件的性能、增加可靠性并延长其使用寿命，必须采取有效的措施散去设备和器件内积聚的热量。传统的聚合物绝缘材料导热系数低，是限制电力设备和电子器件热量散失的瓶颈。制备耐高温、高导热的聚合物复合绝缘材料是解决这一问题的重要办法。本项目以表面改性的氮化硼纳米管（球）为无机导热颗粒，将聚苯硫醚前驱体引入到改性的纳米氮化硼表面，直接进行原位聚合得到耐高温、高导热的聚苯硫醚复合绝缘材料。通过控制反应条件调控聚苯硫醚与纳米氮化硼的比率，调控聚苯硫醚的分子链长度、支化度和聚集态结构等。研究原位聚合制备的聚苯硫醚/氮化硼复合绝缘材料的介电性能和热性能，并与常规共混方法制备的聚苯硫醚/氮化硼复合绝缘材料的相应性能进行对比。建立聚苯硫醚/氮化硼导热复合绝缘材料的性能与结构的关系，为制备耐高温、高导热聚合物复合绝缘材料奠定实验和理论基础。

电力设备和电子器件向小型化、高功率、高电压等方向发展，热管理问题变得突出，对导热绝缘聚合物材料、热别是耐高温可多次加工的材料具有重要需求。本项目以氮化硼等为无机导热颗粒，采用表面引发原位聚合技术，制备得到多种耐高温、可多次加工、高导热聚合物绝缘复合材料。研究了复合材料的介电性能、热物理性能以及热稳定性质，建立导热绝缘复合材料的结构与性能的关系，并评价了这些导热绝缘聚合物材料在电子器件中的热管理行为。.研究发现氮化硼纳米片（BNNS）是一种优异的导热绝缘填料，通过调控其在复合材料内部的分散、分布等，可获得介电、热稳定、机械以及导热性能优异的导热绝缘聚合物复合材料。在复合材料内形成三维网状结构的情况下，BNNS含量仅为9.6 vol%时，热导率可相比基体树脂提高了14倍。采用静电纺丝可制得导热各向异性聚合物复合膜，质量分数为33 %时，PVDF/BNNS纳米复合膜在取向方向热导率可高达16.3 W/(m·K)。.通过本项目，使我国在导热绝缘聚合物复合电介质的研究处于世界领先地位，研究成果为高端电力设备和先进电子器件制造业提供重要的热管理方面的基础材料信息和设计参考。