Elucidation of Carbonization Mechanism of Pitch/Phenolic Resin Mixture and control of the Resultant Carbon Properties

Abstract

Carbonization behavior of pitch/phenolic resin mixtures, especially the interaction between them, was investigated. Three types of pitch, coal tar pitch (CTP), hydrogenated coal tar pitch (H-CTP) and petroleum pich (PP) were used. Carbon yields of pitch/phenolic resin mixtureswere lower than the additivity line for all mixtures and the size of optical texture in coke was minimized when the carbonization yields was minimum value. It was evident that the change of chemical structure of mixtures at the initial stage of carbonization were effected by the hydrogen donor abilities of pitches. In the case of CTP, which have less ability of hydrogen donor than H-CTP, molecular weight of CTP/PR increased and large amount of phenoxyl group was remained even after heat-treatment. On the other hand, no difference of molecular weight and less phenoxyl group were observed for H-CTP. A model of the carbonization mechanism for pitch/phenolic resin mixture was proposed. The fineness of optical texture is considered to be due to the formation of cross-linking structures which is formed by phenoxyl radicals from phenolic resin, at the initial stage of carbonization. But in the case of H-CTP which has high hydrogen donor ability, phenol group in the phenolic resin is decomposed by the attack of hydrogen liberated from H-CTP, disturbing to form cross-linking structures and consequently resulting in large size of optical texture of coke.