Effect of different secondary quinoline insoluble content on the cellular structure of carbon foam derived from coal tar pitch

•The variation tendency of secondary QI content is researched.•The relation between secondary QI content and the cellular structure is disclosed.•It is expected to optimizing the secondary QI content to form appropriate size pores so that to obtain carbon foams with high performance.

Carbon foam was produced using mesophase pitches obtained under different temperatures as precursors, via foaming and carbonization process. The physicochemical properties of mesophase pitch, as well as the microstructure and physical properties of carbon foam were investigated by optical microscope, infrared spectrometer, thermograviment analyzer (TGA), X-ray diffractometer (XRD), scanning electron microscope (SEM) and universal testing machine, respectively. The results show that the amount of secondary quinoline insoluble in mesophase pitches increase with heat-treatment temperature increase, meanwhile, the cell size of carbon foams increased firstly and then reduced. Moreover, the compressive strength of carbon foams also exhibited the same variation trend. The cellular structure of carbon foam can be severely affected by the secondary quinoline insoluble content of mesophase pitch; thus it is critical to tailor the secondary quinoline insoluble content of mesophase pitch for obtaining carbon foam with high performance.