通过发泡和交替层状设计制备高分子/碳系填料吸波材料的基本问题研究

When the carbonaceous fillers, as dielectric absorbents, were employed into polymer to fabricate microwave absorbing materials, the contradiction between the impedance matching and attenuating characteristics seriously impeded the progress of microwave absorbing materials. According to the research status and problems of carbonaceous filler/polymer microwave absorbing materials, the applicant will focus on the designing-fabricating-structure-property of microwave absorbing materials to carry out the innovative researches in two aspects: (1) Through foaming process to adjust the electromagnetic parameters and balance the impedance matching and attenuating characteristics; Investigating the influences of foam structures on the microwave absorbing properties trough quantitative method and detecting the microwave absorbing mechanisms of foam materials. (2) Based on these and combining with the microwave absorbing theory of layer materials proposed by the applicant, the foamed layer and polymer layer will be designed as alternating multilayer structures; The influences of different layer impedance, layer number and layer thickness ratio on the microwave absorbing properties will be investigated. Through these fundamental researches, the microwave absorbing materials with lower reflection loss, broader effective bandwidth, lighter bulk density and lower filler concentration will be fabricated. The ideas, contents and protocols of this research are practicable. The expected achievements will further enrich the microwave absorbing theory of polymer composites and provide new idea and method to prepare high-performance microwave absorbing materials. Therefore, this research has great theoretical and practical significance.

碳系填料作为电损耗型吸波剂添加到高分子中形成吸波材料，存在阻抗匹配特性和衰减特性难以兼顾的矛盾，严重制约了吸波材料的发展。针对高分子/碳系填料吸波材料的研究现状和存在的问题，申请者围绕吸波材料的设计-制备-结构-性能开展两方面创新性研究：（1）通过发泡调控材料电磁参数，实现阻抗匹配特性和衰减特性的平衡，定量研究泡孔结构对吸波性能的影响，探讨发泡材料的吸波机理。（2）在此基础上，结合申请者已提出的层状材料吸波理论，将发泡吸波层和高分子层设计为交替层状结构，研究层间阻抗比、层数、层厚比等对吸波性能的影响。通过这些基础研究，制备反射损耗值更低、有效吸收频带更宽、力学性能更优、密度更小、填充量更少的高性能吸波材料。本申请项目的研究思路、研究内容和研究方案可行，预期成果将进一步丰富高分子复合材料的吸波理论，为制备高性能吸波材料提供新思路和新方法，具有重大的理论和现实意义。

随着吸波材料在雷达隐身技术、微波通信技术及电磁防护领域的广泛应用，对于吸波材料的研发要求也越来越高。新一代吸波材料必须满足“薄、宽、轻、强、抗氧化、耐腐蚀、力学性能优异”等特性。针对吸波材料的研究现状和存在的问题，该项目围绕吸波材料的设计-制备-结构-性能开展如下研究：石墨烯/TPU多孔复合材料的非溶剂诱导相分离法制备及其吸波性能；材料的介电参数-吸波性能评估图谱；石墨烯/TPU多孔复合材料的热诱导相分离法制备及其吸波性能；单层多孔TPU/石墨烯复合材料结构与吸波性能研究；发泡倍率与石墨烯含量梯度层状多孔TPU/石墨烯复合材料结构与吸波性能研究；发泡倍率与石墨烯含量交替层状多孔TPU/石墨烯复合材料结构与吸波性能研究；层数与厚度对梯度及交替层状多孔TPU/石墨烯复合材料吸波性能影响规律研究。取得的重要结果和数据有：当发泡倍率为12.0，石墨烯含量为7.7wt%，厚度为3mm时，石墨烯/TPU多孔复合材料在2-18GHz范围内的最小反射损耗为-21.4dB，有效吸收频宽为6.2GHz，其密度为0.1g/cm3，孔隙率为91.7%；通过控制发泡手段和填料含量可以很好地获得介电参数的平衡值，从而获得优异的吸波性能；通过NIPS发泡，可以在较低的介电常数下，获得较高的介电损耗，从而获得了较好的吸波性能；调节材料厚度可以进一步优化材料的吸波性能；当厚度为1.6mm时，F2-3样品的min-RL为-32.0dB，EB为4.7GHz；石墨烯三维骨架被包覆在层状多孔TPU/石墨烯复合材料的泡孔内壁上，在形成三维导电网络结构的同时，也能大幅度降低石墨烯含量；发泡倍率梯度和石墨烯含量梯度层状结构均能有效提高吸波体的吸波性能；发泡倍率和石墨烯含量交替层状结构均能有效提高吸波体的吸波性能。研究成果可以应用于国防军工、电子电器等国家重要领域。