Simultaneous oxygen uptake and imaging chemiluminescence measurements

Abstract

There are several studies that make a comparison between chemiluminescence and oxygen uptake. Although, there are several reasons to perform this comparison on the same sample at the same conditions, these studies were done by comparing results from separate oxygen uptake and chemiluminescence experiments. It is also postulated that the shape of the chemiluminescence and oxygen uptake curves is not related to the kinetics of the degradation chemistry but to the oxidizing area. To be able to measure the luminescence and the oxygen uptake at the same sample under exactly the same conditions an apparatus is developed in which both measurements can be done simultaneously. To be able to get information on the oxidizing area too, this apparatus is based on imaging chemiluminescence. The induction times determined with chemiluminescence and oxygen uptake are about comparable, although at lower temperatures the induction time according to oxygen uptake is shorter, which might be due to a decrease of the sensitivity of chemiluminescence with temperature. For stabilized and unstabilized polypropylene it was shown that the luminescence curve is related to the amount of material degrading and that the shape of the oxygen uptake and luminescence curves is not related to the kinetics of the degradation chemistry.