Pressure-Strengthened Carbon Fibers from Mesophase PitchCarbonization Processes

Little attention has been devoted to studying the pressures during themesophase pitches carbonization processes and their effects on the as-produced carbonfibers'mechanical properties. Herein, we study the pressure-enhanced graphitization of mesophasepitch and the promoted tensile stresses of the produced carbonfibers using full atomisticsimulations based on reactive forcefields. Results show that pressures increase the tensile stressof as-producedfibers by 3.7-11 times under 1-6 GPa isotropic compressing pressure. Thehighest tensile stress can reach 4.39 GPa in carbonized coal tar pitch at 4000 K under 6 GPa.In experimental work, the pressurized laser-processed mesophase pitch generates less gas andshows more ordered carbonized structures in Raman spectra. This work provides afundamental understanding of the reaction mechanism of carbonfiber production underpressure, and also illustrates a promising method to manufacture mesophase pitch-basedcarbonfibers with exceptional mechanical properties.