Developments in pre-oxidation of polyacrylonitrile nascent fibers

The pre-oxidation of polyacrylonitrile(PAN)nascent fibers determines the final structures and properties of carbon fibers.In this paper,the molecular and crystalline structures of PAN fibers,the pre-oxidation reaction mechanism and the structural transformation during this process as well as the process technologies such as pre-oxidation time and tension have been reviewed.It is prospected that the structural modification of PAN molecular structures,temperature rising,time shortening,cost cutting,cross-sectional homogeneity will be the general trends for pre-oxidation to develop high performance carbon fibers were reviewed.