FT-IR ATR spectroscopy of the edge surface of pyrolytic graphite and its surface/PVC interface

Abstract

The edge surface of pyrolytic graphite (PG) has been oxidized by electrochemical and oxygen plasma treatments. The structure of the oxidized edge surfaces of PG and the interaction between the oxidized surface and poly(vinyl chloride) (PVC) have been studied by means of Fourier transform — infrared attenuated total reflection (FT-IR ATR) spectroscopy. Phenolic hydroxyl groups and functional groups with a carbonyl group are present on the untreated and all oxidized edge surfaces. For all the surfaces, some of the phenolic hydroxyl groups are linked by hydrogen bonds to each other or functional groups with a carbonyl group, part of the carboxyl groups also being linked by hydrogen bonds to each other. Lactone, carboxyl, and quinone structure moieties are formed on the edge surface by the electrochemical treatment. Among the moieties, quinones are mainly introduced to the edge surface by the severe electrochemical treatment. Quinones are not present on the untreated and the plasma-treated edge surfaces. FT-IR ATR spectra provide evidence for the existence of hydrogen bonds between the > C = O groups present on the edge surface and PVC.