Toughening Technology And Principle Of High-Performance Carbon Fiber Composire

This dissertation is composed of two parts.One is the preparation of ultrafine fiber non-woven film which was used to toughening composites by electrostatic spining and the investigation of physical properties of the film. The other is the preparation of carbon fibre reinforced conposite via autoclavemolding which used the ultrafine fiber non-woven film as the toughening material, and the toughening mechanisms were discussed.In the frist part, Phenolphalein Polyetherketone(PEK-C) ultrafine fiber non-woven film of different areal densities such as 10g/m~2,15g/m~2,20g/m~2 was made by electrostatic spining in which Dimethyl Formamide is used as solvent,and the parameters was discussed. Free-defect ultra-fine fiber film could be produced in suitable condition. The diameter of ultra-fine fiber have a homogeneous distribution, mainly ranging from 300 to 600 nm,and the breaking strength of the fibric range from 0.35 to 0.39N·m~2/g. Besides, Polyetherimide(PEI)non-woven films was prepared by electrospinning in the mixed solvent of Chloroform and Tetrachloroethane,which have a nice microstructure and narrow diameter distribution.In the second part, composite laminated plates were made while the PEK-C ultrafine fiber non-woven films were used as toughening material and carbon fiber prepreg as matrix material. And its mechanical properties were tested, compression after impact(CAI) strength in especial. The result indicates that CAI strength up to 359.37Mpa, as 228.4% as the no-toughening composite laminated plates, and the other mechanical properties are not influenced. Microscopic analysis indicates that between composite material layers, the thermoplastic material and thermosetting resins got in to a typical sea-island structure, and the volume fraction of thermoplastic material between layers reached 64%.The bicontinuous structure will prevent crack propagation and absorb energy. This process could increase the interlaminar fracture toughness deeply, and the compression after impact(CAI) strength of composite materials will increase greatly.