Dehydrochlorination behavior of polychloroprene during thermal degradation

The thermal degradation behavior of polychloroprene (PCP) is analyzed by thermogravimetric (TG) analysis and simultaneous thermogravimetry-mass spectrometry (TG-MS). The weight loss in PCP during the thermal degradation is found to occur in four stages. The apparent activation energies are 70-90, 120-180, 250-340, and 290-300 kJ mol^-1 in the first, second, third, and fourth stages, respectively. Furthermore, the degradation products are analyzed in situ by mass spectrometry. HCl is mainly produced in the first and second stages. Chlorinated organic compounds such as 2-chloro-1,3-butadiene and chlorobenzene are produced in the second stage. Aromatics, particularly the polycyclic compounds such as naphthalene, are produced in the third and fourth stages. In addition, the effect of temperature on the dehydrochlorination of PCP during isothermal degradation is also examined. Among select temperatures, the degree of dehydrochlorination of PCP is the highest at 500 °C. It is more difficult to recycle the Cl in PCP as HCl as compared to the Cl in poly(vinyl chloride) (PVC) due to the production of chlorinated organic compounds.