Thermal degradation of poly(vinyl chloride) in alkyl maleates

The thermal degradation of poly(vinyl chloride) has been investigated in diethyl, dibutyl and dioctyl maleate under nitrogen from 160°C to 210°C. The rate of dehydrochlorination was highest in dibutyl maleate and lowest in dioctyl maleate. The apparent activation energy calculated from the average value of the rate constant at each temperature for diethyl, dibutyl and dioctyl maleate was found to be 83.6 kJ mole−1, 112.7 kJ mole−1, and 150.5 kJ mole−1, respectively. The rates of dehydrochlorination and the activation energy observed in alkyl maleates are higher than those observed in ethyl benzoate. In the visible range spectra the absorption at higher wavelengths is considerably reduced in alkyl maleates.