Mechanism of co-pyrolysis of coal-tar pitch with polyvinylpyridine

Abstract

Co-pyrolysis of coal-tar pitch and poly(4-vinylpyridine) cross-linked with 25 wt.% of divinylbenzene (PVP) or the oxidized form of the co-polymer (PVPox) was studied as a possible way of manufacturing of carbonaceous materials enriched in nitrogen. Interactions of pitch with polymers were evaluated using thermogravimetry, elemental analysis, infrared spectroscopy in the DRIFT mode, X-ray photoelectron spectroscopy and optical microscopy. The tendency to depolymerization of PVP on heat treatment results in a little effect of the polymer on the thermal behaviour of the blend. PVPox is a stronger modifier of pitch carbonization behaviour and much more efficient source of nitrogen in the co-pyrolysis. The principal chemical interaction between pitch and PVPox is the dehydrogenative polymerization of pitch constituents induced by polymer oxygen groups. The oxidation of PVP does not affect the nitrogen functionalities transformation on pyrolysis.