| Description |
Polyvinyl chloride is a common plastic that is used in a wide variety of ways. During the past twenty years concern has been raised over the toxicity of polyvinylchloride (PVC) when it is burned. The mechanisms of how PVC degradates under heat have been extensively studied by a number of different techniques, but not by Curie-point pyrolysis-mass spectrometry (Py-MS). By using Curie-point Py-MS I shall try to answer if the PVC mechanism is intramolecular or intermolecular and whether the loss of HCl is the initiating step. Previous studies of PVC involved a number of different methods. These include gas chromatography in combination with mass spectrometry (GC/MS) , thermogravimetric (TG) and differential thermogravimetric (DTG) analysis 2J, and pyrolysis-gas chromatography [3]. The major components of the pyrolysis are hydrochloric acid, benzene, toluene, and naphthalene. Combustion in air, on the other hand, yields carbon dioxide as the major product. The base unit of the PVC chain, vinylchloride, has not been reported in any of the trial studies. It is interesting to note that gravimetric analysis has found that the faster the plastic is heated the more benzene and the less CO2 are produced. Another GC-MS study found that lowering the temperature depressed the benzene formation but did not effect the yield of HCl. |
