Modification of Mesophase Pitch Through the Heat-treatment with Polyvinylcoloride

Abstract

Coal Tar based mesophase pitch was heat-treated together with polyvinylchloride (PVC) in solvent at a temperature range of 265 to 400°C to prepare carbon fiber precursor pitch of better quality. Modification provoked the thermal decomposition and dehydrochlorination of PVC which initiated alkylation, alkylbridging, and condensation reactions of molecules in the pitch, but such modification increased the amount of the benzene insoluble but quinoline soluble fraction without marked rises of softening and spinning temperatures, improving the stabilization reactivity of the pitch fiber and mechanical properties of resultant carbon fiber. Accelerated oxygen up-take by modification reflecting the increase of alkyl groups and enlarged molecular size in the modified pitch may shorten the time necessary for the complete stabilization.