Effect of two-stage thermal treatment on the reduction of quinoline-insoluble in Mesophase pitch

Abstract

ABSTRACT Mesophase pitch (MP) is an important carbon material precursor with excellent physical performance and has a wide application in new energy utilization field. However, the current preparation process leads to a high quinoline-insoluble (QI) content in the MP, limiting its application. Here, we use two-stage thermal treatment to slow the degree of polycondensation during the formation of the MP. The two-stage thermal treatment can facilitate the formation of MP and limit the generation of QI. Moreover, the low content of polycyclic aromatic hydrocarbons (PAHs) in the liquid by-products indicates that the degree of thermal cracking of the feedstock becomes milder. The high content of cycloparaffins in gaseous by-products is due to the better polycondensation of the feedstock. Therefore, a wide area streamlined MP is prepared, which has a high mesophase content (96.8%), a low QI content (20.6%) and a good crystal structure (L c = 57.37 Å, N = 17.64, n = 99.53). At last, a possible mechanism of MP sample formation is discussed, which will provide an insight in the optimization of MP preparation process.