| Polyaniline(PAni) shows extensively potential application in the field of new electromagnetic wave absorbing materials because of its low density, diversified morphology strucures, adjustable electromagnetic parameters and so on. Therefore, how to get the higher wave absorbing performance of Polyaniline and its composite materials has become one of the main research directions in the study of Polyaniline.In this paper, the micro wire template formed by self-assembling of the small molecular 2-anthracen-9-ylmethylene malononitrile (AYM) was used to improve the micro PAni tubes, the absorbing properties of Polyaniline and its composite materials were investigated. The main content of this paper is as follow:The AYM was used as the template for preparing the composite of polyaniline (PAni) and AYM (PAni/AYM) firstly, and then the micro PAni tube was obtained after removing AYM by CH2Cl2. The effects of reaction time and the concentration of dopant HCl on morphology and properties were studied by SEM, FTIR, XRD and TGA. It was shown that when the reaction time was 12h and the concentration of HCl reached 0.1mol/l, the micro PAni tubes with 1～2μm in diameter and tens of micrometers in length could be received. The thermal stability of PAni tube was slightly higher than that of PAni particles. The electric conductivity of micro PAni tube increased as the concentration of HCl increased, the conductivity was about 10-2S/cm while the concentration of HCl is 0.1mol/L.The obtained tubular-shaped Polyaniline and globular-shaped Polyaniline particles were employed as the absorbing fillers and the epoxy as the matrix to prepare the flat composites with 4wt%-20wt% addition of the filler. It was shown that PAni with varied shape mentioned above displayed the similar trend with increasing the content of the absorbing filler, that is, both the real part and the imaginary part of the composite materials at the certain thickness (3mm) rose up and the absorbing performance also increased. At the same time it was also found that PAni with tubular-shaped morphology had higher electromagnetic parameters and absorbing ability than PAni with globular-shaped morphology. For example, with 20wt% incorporation of the tubular-shaped Polyaniline, the lowest reflection loss of the composite was-26.5dB in 10.07GHz, and its reflection loss was almost lower than-10dB in 8.5GHz-12.4GHz; whereas the lowest reflection loss of the composite containing the globular-shaped Polyaniline was-20.7dB in 9.8GHz,and the reflection loss was almost lower than-10dB in 8.4-11.6GHz.By making a preliminary research on the absorbing mechanism of Polyaniline, we found that the absorption cross sections of Polyaniline were almost 1010 larger than its scattering cross sections, and the absorption cross sections of tubular-shaped Polyaniline were larger than the absorption cross sections of globular-shaped particles.The tubular-shaped Polyaniline was mixed with carbonyl iron in various proportion, the obtained composites was employed as the absorbing fillers and the paraffin wax as the matrix to prepare the flat composites. The complex dielectric constants were measured. It was revealed that the permeability (μ′,μ″) of the Polyaniline/carbonyl iron composites were improved by carbonyl iron. The magnetic losses and the microwave absorbing properties of the composites were also improved at the higher frequencies. The range of the reflection loss was widened.Generally in this thesis, PAni with tubular-shaped was prepared and used as electromagnetic absorbing filler, the improvement of the dielectric losses of these tubular-shaped PAni compared with globular-shaped PAni was revealed. The other way was to use the Polyaniline/magnetic particles as electromagnetic absorbing filler to improve the microwave absorbing properties.
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