The in-situ formation of fibrils in coal tar pitch modified with p-methyl benzaldehyde

Modification of coal tar pitch with p-methyl benzaldehyde in the presence of p-toluene sulfonic acid and the in-situ fibrillating mechanism of the modified coal tar pitch were investigated by FT-IR and ~1?H-NMR spectra and SEM. Results show that coal tar pitch undergoes an electrophilic substitution reaction with p-methyl benzaldehyde, transforming the reactive small molecules in the coal tar pitch to macromolecules through methylene functional groups. Moreover, there are many microfibers in the modified coal tar pitch, which grow with modification time, and eventually form linear bundles with a uniform distribution. The modified coal tar pitch is a promising precursor for carbons.