Characteristic Chemical Constitution of Pitch Materials Suitable for the MP Carbon Fiber

Abstract

Abstract Pitch materials suitable for the MP carbon fiber were prepared from petroleum asphalt, coal tar pitch, and polyvinylchloride. The present investigation was undertaken to clarify the characteristic chemical constitution of each suitable pitch material and to define the significance of the special treatment required to prepare the pitch materials. The suitable pitch materials are generally composed of several structural units with aromatic fused rings and more or less alkyl side chains. The suitable pitch material finally obtained from the petroleum asphalt is characterized by a relatively high molecular weight and many quite long alkyl side chains. Special treatment is required to increase the aromaticity and the removal of the low-molecular-weight component. The suitable pitch material from the coal tar pitch is characterized by aromatic fused rings of the condensed type and only a few alkyl side chains, such as, the methyl group. The most desirable effect of the treatment is to accelerate the condensation between molecules without increasing the insoluble matter and to remove the low-molecular-weight component. The results concerning the polyvinylchloride pitch lend some support to the scheme suggested before.