Abstract:
Effect of the maleic anhydride on chemical structure of solid pyrolyzate obtained from the pyrolysis of poly(vinyl chloride) was investigated. Pyrolysis of poly(vinyl chloride) in the presence of maleic anhydride (MAH) was carried out as a function of temperature (ranging between 285 and 375 ?C) and anhydride content (ranging between 20 and 80 % by weight), using a rotating reactor mounted in an electrical furnace. Chemical structure of the pyrolyzate was characterized by using a Fourier Transform Infrared Spectroscopy (FTIR). It was found that by mixing the maleic anhydride with poly(vinyl chloride) prior to the pyrolysis, dehydrochlorination of the PVC rarely occurred, regardless of the temperature and the anhydride content. On the other hand, by adding maleic anhydride during the pyrolysis of poly(vinyl chloride), new FTIR peak at 1858 cm-1 corresponding to a carbonyl group of anhydride could be observed from a pyrolyzate. This was related to a Diels-Alder reaction between polyene intermediate and the anhydride. It was also found that the pyrolyzate contains some insoluble gel and residual chlorine. The above results were discussed in the light of an inhibiting effect of maleic anhydride and some side reactions of polyene.