PHOTOTHERMAL AND THERMAL OXIDATIONS OF RIGID, PLASTICIZED AND PIGMENTED POLY(VINYL CHLORIDE)

This paper reports on experiments to determine the mechanisms of photochemical and thermal oxidations of poly(vinyl chloride) (PVC). The products that are formed when PVC is photolyzed or thermolyzed in the presence or absence of oxygen are investigated by UV-visible and FTIR spectroscopies associated to specific derivatization reactions or physical treatments. These products are identified and general schemes accounting for the mechanisms of photo-oxidation and thermo-oxidation of PVC are proposed. Important differences between these mechanisms are pointed out. The photochemical behaviors of pigmented PVC and plasticized PVC are also studied: it is shown that the general mechanism determined for rigid PVC may be totally applied to these systems.