Study On Carbon Fiber Modified By Cnf For Multiscale Reinforced Epoxy Composites

Nano-composite materials are the combination products of nano technology andfunctional composite materials and have been widely used in the industrial filed(electronic and electricity, automobile, new energy materials and aerospace, etc).However, the application of nano materials is constrained due to its hardly disperse. So,a piece of nano material was processed into a well disperse macro-set carrier and thenfabricated into a piece of nano-composite material with matrix. Because of its shape, itis called nano-paper. The carbon nanofibers show a good application prospect in thefield of nano-composite materials because of its excellent performance of electrical,mechanical, thermal properties and low cost. Carbon fibers are larger, more continuousand excellent mechanical properties, compared with nanometer fibers, which have beenextensively applied to the high performance structure composite materials area.In this paper, carbon nano-fibers are selected as the raw material of carbonnano-fiber paper. Then, according to the problem of the low mechanical strength of thenano-paper, the CNF modified carbon fibers are prepared for the multi-scalereinforcements; the TDE-85epoxy is used as matrix, the nano-paper and CNF modifiedcarbon fiber are used for preparing reinforcements, respectively. Finally, the formermaterials are characterized. The main works are summarized as follows:(1) The vacuum pumping and filtering method and physical deposition methodwere opted for preparing the carbon nanofiber nanopapers, and discussing the effects ofthe process parameters and blinders on the electrical properties. Optimizing thefabrication process, nanopapers with four kinds of contents of carbon nanofibers wereprepared and testing their microstructures and electrical properties, The resistivity valueare lower than74×10-2Ω cm.(2) The casting method was adopted to prepare the nanopaper/epoxy compositematerial, and analyzing the microstructure, electrical property, thermal property andmechanical property of this composite material, it shows that when the temperaturereached100℃, the composite material’s dynamic mechanical thermal propertydegraded quickly. When the temperature reached about290℃, the material started todecompose, and it’s not suitable for a high temperature material anymore. The materialhas conductivity property due to the addition of nanopapers, and its resistivity value islower than4Ω cm.(3) CNF modified carbon fiber reinforcement was prepared, which containscontinuous carbon fiber fabric. The effects of the blinder on the reinforcement electricalproperties were investigated. Preparing reinforcements with four kinds of contents of carbon nanofibers, and their microstructures and electrical properties were tested.Compared with the nanopaper, the reinforcement’s conductivity is better, and itsresistivity value is lower than3.4×10-2Ω cm.(4) Characterizing the obtained CNF modified carbon fiber/epoxy resin compositematerial. The results showed that the storage modulus and electrical properties havebeen improved by adding the CNF modified carbon fibers, and the dynamic thermalmechanical properties of the composite materials began to drop quickly around100℃.The resistivity value of composite was less than8.3×10-2Ω cm and it has an excellentelectrical performance.