The Correlation Between Preparation Technology And Properties Of PAN-based Carbon Fiber

The evolution of structure and changes of properties during the spinning, thermal stabilization, and carbonization of PAN precursor have been studied by many techniques, such as Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Wide Angle X-ray Diffraction (WAXD), Infrared Spectroscopy (IR) and Elemental Analyzer. The tension and density of fibers at different stages were also tested in this paper.Main research contents are as follows:The relationship between properties of different precursor fibers and carbon fibers is studied. We find that through different polymerization systems, the strength of carbon fibers using propylene nitrile, dimethyl itaconic acid, and itaconic acid salt as precursor fiber is low, and the fiber linear density change is bigger. Under same polymerization process, the size of the original silk has a positive relationship with the strength of the carbon fiber.Through different preoxidation process and carbonization process, the relationship between the fiber structure and properties of representation is studied. We find that in the oxidation of low temperature stage applying proper drafting, while high-temperature phase keep fiber fixed length, the intensity of carbon fiber is higher, and the opposite will reduce the strength of the carbon fiber. Under400℃low temperature carbonization process, the strength of the fiber can not be improved, while500℃to600℃of carbonization temperature is suitable for increasing carbon fiber strength.During oxidation and carbonization processes, the strength of PAN precursor fibers is the lowest. PAN precursor fibers are the weakest link during the preparation of carbon fiber fabrication. The internal structure of precursor fibers and carbon content have hereditary on carbon fibers.The groove on the surface of fibers will be smaller with the higher preoxidation temperature. Therefore the oxidation, carbonization processes of precursor fiber should be carried out according to the performance of the original silk.