Phosgene in the thermal decomposition products of poly(vinyl chloride): Generation, detection and measurement

An analytical study was made to determine whether carbonyl chloride (phosgene) is formed during the thermal decomposition of poly(vinyl chloride), PVC. Four methods of decomposition were studied: (1) thermal degradation of PVC in a resistively heated furnace, (2) electrical overloading of a PVC clad wire, (3) electrical arcing between electrodes partially covered with PVC, and (4) electric arc initiated flaming combustion in a cup furnace. Results are reported which show that significant quantities of phosgene can be generated from PVC by the electric arc method. Lesser amounts were found in the other scenarios. The measurements, identification and quantification of phosgene in the decomposition product, were obtained through the use of gas chromatography, infrared spectroscopy and mass spectroscopy. While the study was not mechanistic in nature, phosgene is postulated to result from secondary reactions of the PVC products. Reaction mechanisms are suggested.