Preparation Of Double - Walled Carbon Nanotube Thin Films And Its Electromagnetic Shielding Performance

The traditional electromagnetic shielding materials of metal have disadvantages on heavy quality, big dense and so on. The characteristics of metal limit its development.Nowadays, the hot of research electromagnetic shielding materials is filling lightweight conductive polymer material with carbon nanotubes(CNTs), the value of shielding is about only 20 d B, the reason is that the dispersion of CNTs performance so bad, result in the amount of CNTs in the composite is low, difficult to disperse and poor conductivity. The key to improve the electromagnetic interference shielding effectiveness of carbon nanotubes is increased the content of carbon. Based on the reasons,The research of carbon nanotubes electromagnetic interference has been studied.The prepartion of lightweight,efficient CNT films, include the following contents:By a floating catalyst chemical vapour deposition, N-hexane is used as the carbon source, ferrocene as the catalyst precursor, thioene as the catalyst and methanol to adjust the growth of CNTs. The prepared CNT films has lightweight,excellent flexibility and folding.By filling magnetic material in CNT films, a lot of Fe particles can be obsrved on the wall of CNTs.The method of filling magnetic material by filling ferrocene/ethanol to CNT films prepared shielding films. And the intermediates of ferrocene/CNTs has been prepared.Ferrocene can decomposition Fe partiticles at a high temperature, then the films with magnetic.By thermo gravimetric analysis,the quality percentage of Fe from21% increased to 35%,and magnetization saturation from 35.43 emu g-1increased to47.35 emu g-1 and shielding effectiveness has a big improvement.The method of filling magnetic material by filling ferrocene/methanol to CNT films prepared shielding films.Methanol can reduce the concentration of carbon source,and control the supply of carbon atoms in the process of reaction and carbon source decomposition speed. Methanol also can increas the amount of ferrocene dissolved.The wall of CNT adhered to more Fe particles.In this experiment, another quartz capillary was added to pump ferrocene/methanol solution in the reactor,preparation high performance shielding film directly. By thermo gravimetric(TG)analysis,the quality percentage of Fe from 21% increased to 31.5%,and magnetization saturation from 35.43 emu g-1 increased to 57.3emu g-1. The shielding effectivenessreach 60 d B at 5GHz and 19 GHz.Fe SO4 as the main salt and H2SO4 as corrosin inhibitor in the method of electroless plating.Adjusting the PH of plating solution in the range of 2 to 3, and the current in the range of 0.1A to 0.2A.Using iron plate as the anode material and CNT films as the cathode materials, covering a layer of nano iron oarticles.By thermo gravimetric analysis,the quality percentage of Fe from 21% increased to 22.4%,and magnetization saturation from 35.43 emu g-1increased to 38.35 emu g-1.By filling magnetic material, the quality percentage of Fe, magnetic, and shielding effectiveness have a a great increase. Electroless plating as a new method, the electromagnetic shielding of CNT macrofilms have great increase.