Modification of naphthalene-derived mesophase pitch with benzoquinone

Abstract

Naphthalene-derived mesophase pitch (NMP) was chemically modified with p-benzoquinone (BQ) at relatively low temperature, then carbonized and graphitized. An activated Diels-Alder reaction between NMP molecules and BQ occurred at 115 °C followed by a dehydration reaction at 158 °C. The modified NMP changed its texture from anisotropic to isotropic with increasing BQ concentration. The carbon yield of modified NMP also increased with BQ concentration up to 81.4 from 74.6%. No coalescence of the modified NMP powders was observed during carbonization and graphitization when modified at BQ NMP ratios higher than 10 10 . The bulk density of the disks molded and carbonized at 1000 °C was a maximum at a 10 10 composition among the four compositions examined. Molecules in NMP were found to increase in molecular size and be substituted by carbonyl groups through the Diels-Alder reaction of BQ. Such molecules lose stacking order and fusibility, forming a more isotropic texture, while the carbon yield increases.