Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5201618 | Polymer Degradation and Stability | 2015 | 11 Pages |
Abstract
The activation energies of two poly(isobutylene-co-isoprene) (IIR) copolymers containing 0.9 and 1.85 mol% isoprene were determined under thermo-oxidation conditions from ambient to 100 °C. Transmission Fourier Transform Infrared (FTIR) spectroscopy was used to follow the functional group development. Ketone generation was the dominant oxidative product above 70 °C whereas below this temperature, carboxylic acid formation was prevalent. Non-Arrhenius kinetic behavior was observed due to curvature taking place near 70 °C. The estimated activation energies for the high and low temperature degradation processes were 85-87 kJ/mol and 49 kJ/mol. Test results were interpreted in terms of two competing thermo-oxidative zones, isobutylene and isoprene, the latter operating at low temperatures as shown by isoprene depletion and chain scission reactions. A set of thermo-oxidative reactions for IIR copolymers is proposed comprising allylic and addition reactions at the isoprene unit.
Related Topics
Physical Sciences and Engineering
Chemistry
Organic Chemistry
Authors
Richard J. Pazur, Ivan Petrov,