Preparation And Properties Of Polyether Ether Ketone-based Electromagnetic Shielding Composite

Poly (ether ether ketone)(PEEK)resin has been widely applied in the field ofaerospace, electronics, transportation, energy and chemical for its good performance.The needs of the electromagnetic shielding material has promoted the development ofcorrelative science and technology, and attracted extensive attention of scientists. Inthis paper, the different conductive fillers were incorporated into the Poly (ether etherketone) resin to prepare high-performance electromagnetic shielding compositematerial. Carbon nanotubes (CNTs), carbon fiber (CF), Graphite (Graphene) and othercarbon materials become the ideal choice for preparation shielding compositebecause of their unique structure, excellent performance and so on. In this thesis, theresearch had been carried out for design, fabrication and characterization of the highperformance electromagnetic shielding composites based on PEEK resin and theabove mentioned carbon materials.Firstly, poly (ether ether ketone)/carbon materials composites were prepared bymelt blending method and electromagnetic shielding properties, mechanical propertiesand thermal properties of composites were synthetically analyzed and compared.We found that the shielding properties of the composites with different carbon fillerwere different. The PEEK/Ni-G composites improved shielding efficiency of10dB inthe K-band (18-27GHz), the PEEK/Ni-CF composites improved shielding efficiencyof5dB in the K-band and10dB in the X-band and Ku-band., the shieldingefficiency of PEEK/D-G composites has been significantly improved in thefrequency range of8GHz-18GHz and reached up to40dB. The composites withdifferent component and properties could be designed and prepared on the specificrequirements of the electromagnetic shielding performance materials. PEEK/CNTscomposites showed a higher shielding effectiveness in a wider frequency range(8GHz-30GHz) and the maximum shielding performance of the composites couldreach70dB, at the same time, the dosage amount of the CNTs in the composites wasrelatively lower. The results were due to the high specific surface area, the long diameter ratio and layered spiral structure of carbon nanotubes. The shieldingeffect of PEEK/CNTs composites mainly depend on the absorption loss and thereflection loss is very little, especially in the frequency range of8-18GHz, themagnetic induction of the electromagnetic wave is the most obvious and theabsorption loss is significant. The PEEK/CNTs composites can be used as abroadband, lightweight and efficient shielding material.And then, we studied that the effect of the different melt index of PEEK matrixand the different modified carbon nanotubes on the properties of PEEK/CNTscomposites. The distributed CNTs, mica-type CNTs and titanium dioxide-type CNTscould disperse well in the PEEK matrix to improve the mechanical properties ofcomposites; especially the elongation at break but the shielding performance didn’tincrease remarkably. The shielding performance of the composites based on the PEEKwith the high melting index was heightened than that of the composites based on thePEEK with the low melting index when the content of CNTs in the composites werethe same. Moreover, the melting fluid of PEEK was improved in compositesprocessing and reduce the energy consumption of production. We also addedhigh-temperature lubricant into the composites to reduce the processing viscosity ofthe polymer, i.e. improved the melt flow during composites processing, which couldpromote the dispersion of carbon nanotubes in the PEEK matrix of the low meltingindex. The shielding properties of compositecould be increased by5-10dB in thefrequency range of40MHz-30GHz by introducing the high-temperature lubricant. Wecan design the composites based on the properties of the shielding materials bychoosing the different modified carbon nanotubes, different PEEK resin of the meltingindex or adding high-temperature lubricant.The research results indicated that PEEK/carbon material composites are theexcellent electromagnetic shielding materials with the excellent mechanical properties,high thermal stability, low density and low molding shrinkage, etc.