Chemical Modification Of Pan Precursors And Influences On Resultant Carbon Fibers

In order to prepare high performance carbon fibers, polyacrylonitrile (PAN) copolymer precursors were chemically modified to ease up exothermic reaction during oxidation and improve the structure of fibers and thus increase the tensile strength of carbon fibers.The properties and structure of treated and untreated fibers were compared by using Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FT-IR), X-Ray Diffraction (XRD),Scaning Electron Microscope (SEM)and measurements of water content, density and tensile strength. The results showes the fibers chemically modified cyclize5℃～11℃earlier and exothermic reaction finishes later, as the result intense exothermic reaction is relaxative, which is helpful to control the structure of fibers. The chemical modification of PAN precursor can increase the tensile strength of the carbon fibers by16.3%compared to the fibers without treatment during intermission experiment. Besides, the technical conditions in manufacturing high performance of carbon fibers from A-3modified PAN fibers were explored. The tensile strength of carbon fibers increases by17.7%, reaching4.05GPa. For the appearance of carbon fiber is improved, the microcrystalline dimension decreases, the density increases and thus micro void content decreases.