Effect of molecular weight and the molecular weight distribution of a condensed polynuclear aromatic resin on the constituents and properties of their pyrolysis products

Three condensed polynuclear aromatic resins with different molecular weights (MWs) and MW distributions were heated at 900, 1500, 2200, 2600 and 3000 °C for 2 h. The resulting carbons were characterized by XRD, helium pycnometry and a powder electrical resistance test. The graphitic, amorphous and turbostratic constituents in the carbons were obtained from XRD. Results showed that both the MW and the MW distribution in the resins played important roles in the properties and constituents of the carbons produced from them. The larger the MW and the narrower the MW distribution, the higher the graphitic content in the carbons produced at 3000 °C. The larger the MW and the wider the MW distribution, the higher the apparent density of the carbons produced at the same pyrolysis temperature. The effect of MW on the powder resistance of the carbons is negligible.