Optimization of stabilization and carbonization treatment of PAN fibres and structural characterization of the resulting carbon fibres

The properties of carbon fibres made from PAN are controlled by the heat treatment cycles during stabilization and carbonization. Optimum conditions can be derived by simple but time-consuming trials. The paper presents an indirect laboratory method, which is based on TMA and DSC measurements during the stabilization period. Results from this method contribute additionally to the explanation of the various simultaneously occurring chemical reactions, mainly dehydrogenation, intra- and intermolecular cyclization. Shrinkage measurements during stabilization under time linear heating show the start and end of the chemical stabilization reactions. The optimum stabilization conditions are derived from the shrinkage behavior as a function of the heating rate. As the stabilization is strongly affected by the heat of reaction, DSC measurements contribute to the accuracy but also to the explanation of the results from the TMA method. These stabilization conditions were applied for the preparation of carbon fibres which are characterized by mechanical and physical methods.