Preparation of isotropic spinnable pitch with high-spinnability by co-carbonization of coal tar pitch and bio-asphalt

Abstract

Co-carbonization of coal tar pitch (CTP) with bio-asphalt (BA) was performed to prepare spinnable pitch with suitable softening point and excellent spinnability for general purpose carbon fiber. The co-carbonization mechanism and the correlation between spinnability and molecular structure of prepared pitch were clarified. BA produced from the pyrolysis of biomass is abundant of aliphatic units and oxygen-containing groups, leading to high reactivity during carbonization. The co-carbonization reactions mainly depend on the mutual cross-linking among CTP and BA molecules, which are principally triggered by active oxygen-containing groups of BA. The formed cross-linked macromolecules could further promote the polymerization degree of pitch molecules; thus, the spinnable pitch with suitable softening point could be obtained by simply thermal treatment of blended pitches at a relatively moderate condition (<350 °C). The properties of the pitch could be optimized by changing the blending ratio of CTP to BA. Moreover, the prepared carbon fibers demonstrated distinct features, especially surface profiles. It is expected to provide a new strategy for the preparation of isotropic spinnable pitch in a relatively simple approach.