Influence of the morphology of samples in the pyrolysis of PVC

PVC was used as a model substance to study the dependence of thermal measurement data on the preparation and morphological characteristics of samples The PVC treated was a commercially available suspension polymer, Ongrovil S 155, produced by the Borsodi Vegyi Kombinát. The whole thermal process was followed by TG and DTG measurements in air and argon atmospheres by means of a Du Pont 990 Thermoanalyzer. Evolved-gas analysis was performed with a home-made apparatus. Pyrolysis gas chromatography was accomplished using a Hamilton type pyrolyzer and a Carlo Erba Chromatograph furnished with a flame ionization detector. The investigations showed benzene and other components to be evolved from the initial polymer and an alteration depending on the morphological characteristics of the samples. This was suggested to be due to the different mechanisms of thermal degradation of the PVC.