TG/FTIR study of the thermal pyrolysis of EVA copolymers

The interpretation of the FTIR spectrograms corresponding to the temperatures of maximum decomposition rate for each decomposition step shows the formation of acetic acid, CO and CO2 in the first decomposition step (elimination of the acetoxi groups), and the formation of a complex hydrocarbon mixture in the second decomposition step (cracking of the polymeric chain) including alkanes, alkenes and mononuclear aromatic compounds. The evolution of the ratio of the absorbance of bands at 3015 cm−1 (olefinic CH stretching) and 2925 cm−1 (asymmetric stretching of CH2), representative of the evolution of the ratio 1-alkenes/alkanes, shows a minimum, for the second decomposition step, close to the temperature of maximum decomposition rate, which reflects the differences in the evolution of the alkanes and alkenes in the two stages of the second decomposition step.