高介电常数纳米碳/双马来酰亚胺树脂复合材料的空间结构与介电性能的关联机制研究

Polymeric composites with high dielectric constant (Hik-PMC) have been gained great attentions worldwide, achieving low dielectric loss, high electric strength and the combination of structural and functional performances are the main targets of the research on Hik-PMC. The influence of the components (functional fillers and resins) on the dielectric properties has been widely and deeply studied; however less attention has been paid on the relationship between the spatial structure and dielectric property as well as the nature behind. Previous investigations show that based on the same functional fillers and polymers, by changing the spatial structure, the dielectric properties of the resultant composites were greatly changed, but the relationship between the the spatial structure and dielectric property as well as its mechanism are still not revealed. In this proposal, the representative of high performance thermosetting resins, bismaleimide resin, is selected as the matrix; while nanocarbon, carbon nanotube or graphene is chosen as the electric conductor. By designing new spatial structures based on the combination of gradient distribution, orientation, and/or laminate structures, a series of new composites with different spatial structures will be fabricated. The main discussion subjects include the charge accumulation, rearrangement and kinetics of the composites in electric field, the correlation between spatial structure and dielectric properties as well as the stability under typical external fields; the component-processing-spatial structure-dielectric properties relationship; the typical integrated performances (thermal and hot-wet properties, dynamic/static mechanical properties) of the composites with good dielectric properties. Through these investigations, new high performance Hik-PMCs based on the controlling of spatial structure will be developed.

高介电常数聚合物基复合材料（Hik-PMC）是研究十分活跃的功能材料，实现低介电损耗、高介电强度及结构/功能一体化是Hik-PMC研究的关键。复合材料组成（功能体和聚合物）对介电性能的影响已得到充分研究，而空间结构与介电性能关联机制的研究则刚刚起步。前期研究证明基于相同的复合材料组成，改变空间结构可得到介电性能迥异的材料，但空间结构与介电性能关系及其本质不明。本项目以双马来酰亚胺树脂为基体，分别以纳米碳黑、碳纳米管、石墨烯为功能体，以梯度、取向和层状结构为基本空间模型，设计构筑空间结构不同的系列复合材料；探讨复合材料在电场作用下发生的极化、电荷积累与重排及其动力学，关联空间结构与介电机制的关系；研究典型外场下空间结构及介电性能的稳定性；构筑材料组成－工艺－空间结构－介电性能关系；考察优选复合材料的其他重要性能（耐热、耐湿和动/静态力学性能），制得基于空间结构调控的新型高性能Hik-PMC。

实现低介电损耗、高介电强度及结构/功能一体化是高介电常数聚合物基复合材料研究的关键，而介电损耗高、击穿强度低是高介电常数导体/聚合物复合材料的共有缺点。已有研究表明，通过构筑新颖的空间结构，可以克服这些缺点，但是，相关研究尚不充分，空间结构与介电性能关联机制的研究刚刚起步。本项目重点展开了四个方面的研究工作：（1）具有不同空间结构的纳米碳树脂复合材料的设计、制备与结构表征。先后设计了多层结构和单层结构两大类。在多层结构中，设计制备了纳米碳分别以梯度分散、均匀分散及其在一定方向取向的复合材料；设计制备了绝缘层组成不同和层数不同的复合材料。单层结构中，纳米碳分布于聚合物共混物的不同相中或者沿一定方向取向。（2）纳米碳树脂复合材料的空间结构与介电性能关系规律的研究。提出了多种构筑新颖空间结构的方法，分别是基于多相聚合物体系的相分离、基于梯度和层结构设计、基于树脂与纳米碳导体相互作用、基于导体间物理作用、基于新型三维结构功能体制备、基于绝缘层设计（云母纸、六方氮化硼）、基于新型杂化导体设计等；系统研究了各复合材料的介电性能、击穿强度和储能密度及其机理。（3）在典型频率和温度场条件下，研究复合材料的介电性能的稳定性及其改进策略。重点研究了三维介电泡沫的复合材料的介电性能稳定性，探索了提高复合材料的介电性能稳定性的方法，分别从界面结构设计和掺杂技术两个方面有效提高了介电性能的频率稳定性和温度稳定性。（4）面向电子产业对透明高介电常数薄膜的需求展开工作。在研究介电性能的基础上，考察了复合薄膜的透明性、热性能和力学性能，获得了综合性能优异的高介电常数聚合物基复合材料，为实现结构/功能一体化提供理论和实践依据。