FT-Raman spectroscopic study of the formation of polyenes during thermal degradation of poly(vinyl chloride) and poly (N-vinyl-2-pyrrolidone) blends

In situ degradation of poly(vinyl chloride)/poly (N-vinyl-2- pyrrolidone) (PVC/PVP) blends has been studied by Fourier-transform Raman spectroscopy. PVP acts as a destabilizer in the thermal degradation of PVC as manifested by the reduction of temperature for the onset of degradation and the time the polymer is held at a particular temperature for this onset. Increasing the amount of PVP in the blends decreases the dehydrochlorination temperature and time. In blends containing high PVP concentrations, polyene bands dominate over nondegraded PVC bands. Maximum polyene lengths of around 35 were achieved. High PVP ratios and prolonged degradation at higher temperatures resulted in a decrease in mean polyene length due to crosslinking and oxidative scission.