The Effect Of Tension On The Structure And Properties Of Pan-based Carbon Fiber During Its Preparation

The mode and degree of the transformation process from PAN fiber to carbon fiber determines the structure and properties of resultant carbon fiber, so it is meaningful to study PAN fiber’s morphological structure and its relationship with outer fields in this process. Lots of works were done on reactions and its influence of contract, but most of them were carried out based on intermission experiment. In order to prepare high performance carbon fiber and disclosure the relationship of between temperature, thermo chemical reaction, structure and properties, based on temperature, I studied the relationship between tension and temperature, thermo chemical rcaction,and got some useful data and warrant for further study the influence of tension on structure and properties of carbon fiber by means of testing measure such as EA,XRD,DSC,FTlR.Results show(1) The tension trends of PAN fiber are not identical and even opposite because of the difference in structure, temperature and drawing ratio. These trends depend on one or some of them (2) When the temperature is lower (<235℃), the chemical reaction is occurred in disordered domain firstly and leads to little change in crystallinity. And when the energy provided by heat treatment temperature exceeded the energy which to change the molecular conformation, the thermo chemical reaction expanded to the ordered domain, which resulted in the dramatic decline of crystallinity.(3) the processes, which the molecular chains experienced during their transition to carbon fiber, were testified to include initially the improvement of orientation structure because of drawing and subsequently the disorientation during the oxidative stabilization and finally the dramatic incline of orientation degree during carbonization.