Effect of Current Thermal Annealing on Thermal Conductivity of Carbon Fibers

The polyacrylonitrile based carbon fiber (PAN-CF) was measured by transient electrothermal technology (TET), and the experimental phenomena were analyzed based on numerical simulation method to explore the effect of annealing temperature on thermal conductivity of PAN-CF. The relationship between graphitization and thermal conductivity of PAN-CF under current thermal annealing was analyzed. The thermal conductivity increases with the increases of annealing temperature. The highest average thermal conductivity is 16.27 W/(m•K). Ultimately, the average thermal conductivity of PAN-CF increases by 3.45 times. The temperature distribution along axial direction of fiber is not uniform in current annealing process. PAN-CF sample is broken at midpoint, and the temperature and thermal conductivity of sample breakpoint are maximum, which are 3 867 K and 96.74 W/(m•K) respectively. The thermal conductivity of sample breakpoint is 6.51 times higher than the average thermal conductivity under the same annealing current. The degree of graphitization of PAN-CF increases after current annealing, and the hybridization effect of carbon atoms reduces defect density of PAN-CF microstructure. Therefore, the thermal conductivity of PAN-CF increases after current annealing process. © 2020, Materials Review Magazine. All right reserved.