螺旋型非晶态碳纳米管/双马来酰亚胺树脂(HACNT/BMI)复合材料的制备及吸波机理

New electromagnetic wave absorbing materials are the hotspot and focus of research in national defense science and technology. Carbonmaterials, as light absorbing materials, have been widely valued by researchers. In this study, we prepared helical amorphous carbon nanotube/bismaleimide (HACNT/BMI) resin composites and investigated their electromagnetic wave absorbing properties. We used helical amorphous carbon nanotubes as adsorbing agents, bismaleimide as matrix to prepare HACNT/BMI resin composites. Helical amorphous carbon nanotubes were prepared by floating catalytic chemical vapor deposition method. Scanning electron microscope (SEM), transmission electron microscope(TEM), X-ray diffractometer (XRD) and Raman spectroscopy were used to characterize the morphology and structure of samples. The electromagnetic parameters of HACNT/BMI composites were measured by vector network analyzer. The results showed that the increasing in the content of absorbing agent enhanced the electromagnetic wave absorbing properties of HACNT/BMI composites. The maximum absorption peak reached -18.35 dB, the widest absorbing bandwidth reached 2.56 GHz(9.52~12.08 GHz) when the R_L belows -10 dB, and the reflection loss exceeded 97%. Moreover, the absorption peak of HACNT/BMI composites with higher content of HACNTs shifted towards lower frequency compared to that of the sample with lower content of HACNTs. Our results indicate that the helical structures of HACNTs plays an important role in enhancing the electromagnetic wave absorbing performance of HACNT/BMI composites. The HACNTs could increase the possibility of multiple reflection of electromagnetic wave and the path length of scattered waves. As a result, the energy loss of incident electromagnetic wave was increased.