Researching On Microwave Absorption And Electromagnetic Interference Shielding Properties Of Carbon Nano Materials

As the electronic equipment has been increasing at a noticeable rate,the materials with excellent microwave absorption and electromagnetic interference(EMI)shielding performance are urgently need.Multi-walled carbon nanotubes(MWCNTs)buckypapers with Mn nanoparticles(NPS)interlayer were fabricated via monodisperse solutions through layer by layer vacuum filtration,Ni deposited onto(MWCNTs)buckypapers were fabricated via vacuum filtration method and magnetron sputtering and ehtylene propylene diene monomer rubber with graphene nanoplatelets(GnPs/EPDM)were fabricated by mixing,ultrasonication and compression.Firstly,the microwave absorption and EMI shielding effectiveness(SE)of the MWCNTs buckypapers with Mn NPS(0~30wt%)interlayer were tested.When the blended Mn NPS content in buckypapers is 20wt%,there are evidently two larger absorption peaks(-13.2dB at 3.41 GHz,-15.6dB at 3.52GHz)of the buckypaper with an absorbing thickness of 0.1mm.The buckypaper exhibited much higher EMI SE of average value up to 42 dB.Secondly,EMI SE of Ni deposited onto MWCNTs buckypapers with different deposition time(0min,30 min and 60min)were tested in frequency range of 2-18 GHz,including S-band,C-band,X-band and Ku-band.The 60 min Ni-deposited MWCNTs buckypapers exhibited much higher EMI SE of average value up to 42.59 dB with the thickness of 0.105 mm.Based on reliability study,the 60 min Ni-deposited MWCNTs buckypapers retains 94.3% of its EMI SE after 500 cycles of mechanical bending.Finally,the GnPs/EPDM was fabricated as a flexible EMI shielding material.Further investigation demonstrates that the 8wt% GnPs/EPDM with only 0.3mm in thickness shows excellent electrical conductivity(28.3S/m),thermal conductivity(0.79W/mK)and good mechanical strain(210%).Besides,the 8wt%GnPs/EPDM exhibits a EMI shielding effectiveness(SE)up to 33 dB in the X-band(8.2~12.4GHz)and 35 dB in the Ku-band(12.4~18GHz),superior to most of the reported rubber matrix.Additionally,the GnPs/EPDM shows excellent flexibility and stability with 95% and 94% retention of EMI SE even after repeated bending for 5000 times and corrosion for a week.