非晶碳纳米管多层吸波复合薄膜的制备及其吸波机理研究

The investigations of nano-stealth materials are important frontiers and hot research topic in the defense science and technology. It has important value for the scientific research and practical use to improve the narrower bandwidth and lower electromagnetic wave absorptivity of stealth material. In this project, a novel nano-stealth material based on amorphous carbon nanotubes(ACNTs) having large bandwidth and high absorptivity will be proposed and investigated. Multi-layer ACNTs/resin composite films using modification ACNTs as electromagnetic wave absorber are synthesized by mechanical rolling technology and the nanocomposite system of ACNTs modified resin was established. The electromagnetic wave absorbing properties, micro-structure and mechanical behavior of ACNT films are characterized and analyzed. The effects of modification ACNTs on the electromagnetic wave absorbing performance of composite films are also studied systematically.Experiments on how to improve the electromagnetic wave absorbing performances, as well as affect the factors of wave absorbing properties, mechanism and influence rules, will be carried out deeply. Based on quantum mechanics and classic electromagnetic theory, the mechanism of electromagnetic wave absorbing and influence rules of multi-layer ACNT films will be discussed. It is believed that this multi-layer ACNT film has a favorable ability of electromagnetic wave absorption in the bandwidth ranges of 2-18GHz with absorber thicknesses of 0.5-2mm. It greatly reduce the radar cross section(RCS) and increase the absorptivity of electromagnetic wave. The absorptivity and bandwidth of electromagnetic wave is expected to reach 97%(-15dB) and 8 GHz or even higher respectively.

纳米隐身材料研究是国防科技中重大前沿和热点问题，拓宽隐身材料较窄的频率带宽和提高其较低的电磁波吸收率具有重要的科学研究和实用价值。本项目研究基于非晶碳纳米管的新型纳米隐身材料可大幅拓宽频率带宽和提高吸收率。以改性非晶碳纳米管作为吸波剂，建立非晶碳纳米管改性树脂基纳米复合体系，采用机械压延技术制取非晶碳纳米管/树脂多层吸波复合薄膜；通过对多层吸波复合薄膜进行微观组织结构、电磁波吸收及力学性能的表征测试分析，揭示改性非晶碳纳米管对复合材料吸波性能的影响，及其用来提高电磁波吸收性能的影响规律和作用机制；基于量子理论和经典电磁理论提出多层复合薄膜的吸波机理，并对吸波性能进行理论计算。预期研制的非晶碳纳米管多层吸波复合薄膜厚度在0.5～2mm，频宽在2～18GHz 范围内具有良好的电磁波吸收能力，能够大幅降低雷达散射截面(RCS)，力争对电磁波的吸收率达到97%（-15dB）、带宽达8GHz及以上。

纳米隐身材料研究是国防科技中重大前沿和热点问题，拓宽隐身材料较窄的频率带宽和提高其较低的电磁波吸收率具有重大的科学研究和实用价值。本项目完成了基于非晶碳纳米管的新型纳米隐身材料可大幅拓宽频率带宽和提高吸收率。以改性非晶碳纳米管作为吸波剂，建立了非晶碳纳米管改性聚氯乙烯（PVC）树脂基纳米复合体系，采用机械压延技术制取了非晶碳纳米管/树脂多层吸波复合薄膜；揭示了改性非晶碳纳米管对复合材料吸波性能的影响；提出了基于非晶碳纳米管多层复合薄膜的吸波机理，并对吸波性能进行理论计算。.以改性多壁碳纳米管为吸收剂，聚氯乙烯(PVC)为基体，制备出改性MWCNT/PVC复合材料。复合吸波薄膜厚度在0.5～4mm，当吸波复合材料为单层结构时，MWCNT-Ni/PVC复合材料的吸收频宽（<-10dB）达到（5.24GHz）；当吸波复合材料为双层结构时，在2~18GHz范围内出现两个<-10dB的频率区域6~8.4 GHz和17.36~18GHz，可在多频段范围内吸收电磁波。项目重点以非晶碳纳米管（ACNTs）作为电磁波吸收剂，PVC等树脂为基体，制备出ACNT/PVC复合材料；与MWCNT/PVC复合材料相比，其抗拉强度和弹性模量大，且吸收峰峰值较大，吸收频宽（<-10dB）较宽，吸收峰向高频区域移动。在2~18GHz范围内，单层ACNT-Fe3O4/PVC复合材料吸收峰峰值为-25.7dB，吸收频宽（<-10dB）为4.56GHz；ACNT-La(NO3)3/PVC复合材料吸收峰峰值为-25.0dB，吸收频宽（<-10dB）为5.52GHz。当吸波复合材料为双层结构时，在2~18GHz范围内均出现两个<-10dB的频率区域，其中ACNTs-Fe3O4/ACNTs-La(NO3)3双层PVC基复合材料的吸收峰峰值为27.2dB，吸收频宽（<-10dB）近8GHz。基于经典电磁理论，建立了多壁碳纳米管和非晶碳纳米管电磁波路径损耗的数学模型，由于电磁波入射到多壁碳纳米管表面时仅进行一次反射，而入射到非晶碳纳米管表面时，电磁波进入管壁内部，进行了多次反射，传播路径增长，路径损耗增大，从而使非晶碳纳米管的电磁波吸收性能优于多壁碳纳米管。.通过本项目研究，开拓了基于非晶碳纳米管改性树脂复合材料作为吸波材料在航空航天领域有着广泛的应用前景。