Activation energy of poly(isobutylene) under thermo-oxidative conditions from 40 to 100 °C

The thermo-oxidation of poly(isobutylene) (PIB) has been investigated by using accelerated heat aging in the 40-100 °C range and functional group analysis by transmission Fourier Transform Infrared (FTIR) spectroscopy. Time-temperature superposition (TTS) and the Arrhenius approach were used to calculate activation energies. Oxidation product evolution was continuous within the temperature range. PIB displayed excellent TTS and linear Arrhenius behavior leading to an energy of activation (Ea) range of 116-125 kJ/mol for the growths of the carbonyl (ketone), hydroxyl and β-lactone groups. The similarity between the Ea values strongly suggests that the reactions that they comprise are interrelated, agreeing with the currently accepted oxidation mechanisms of PIB.