Investigation of the thermal oxidation of a polybutadiene by headspace sampling-gas chromatography

A novel method was developed, utilizing headspace sampling in conjunction with gas chromatography, to quantitatively follow the thermal oxidation in air of a low molecular weight, hydroxy-terminated polybutadiene. This method was found to offer an efficient and simple technique by which to analyze both the rate and the extent of oxidation of the polymer. Rate studies of the oxidation revealed an induction period followed by self-catalyzed oxidation, the rate of which quickly becomes controlled by diffusion of oxygen into the polymer. By determining the rate of oxygen consumption at various temperatures, an Arrhenius-type plot was derived and an activation energy value of 13 kcal/mol was calculated. The relative effects on oxidation of a number of common antioxidants and organometallic cure catalysts were also determined by this technique.