Photo‐oxidation of polymers: Validation of oxygen uptake and relationship with extent of hydroperoxidation

Abstract

ABSTRACT:In this piece of work we focused our attention on the peroxidation step and alongside considered hydroperoxides as probes for the overall oxidative process. This technique of oxygen uptake actually monitors the amount of oxygen consumed during polymer degradation. Our present work aimed to investigate this technique to evaluate the oxygen uptake during in situ photoirradiation, under controlled atmosphere. Our experimental results clearly elucidate that the oxygen consumption data accounts for a very early stage of aging during the photo-oxidation of polymers and provides us with an accurate and sensitive diagnosis about the formation of hydroperoxides. A straight-line relationship was exhibited under our experimental conditions while observing a relation between oxygen pressure drop and hydroperoxide content in the polymer. This correlation was dependent upon the nature of polymer and of course on the aging conditions (temperature, irradiation, oxidative atmosphere). The impact of environmental atmosphere on aging was particularly kept in mind. To conclude, we emphasized that oxygen uptake is a promisingly powerful tool to identify the impact of the overall environmental parameters on the polymer photoaging. An important implication was on the understanding of atmospheric factors (including pollutants such as O 3 , NO x , etc.), which is usually given minor importance, on the degradation of polymer upon outdoor weathering.

Singlet Oxygen-Induced Photodegradation of the Polymers and Dyes in Optical Sensing Materials and the Effect of Stabilizers on These Processes

“…A broad variety of methods are employed to analyze and describe photodegradation processes in polymers, 7,61,62 one of which is the measurement of oxygen consumption (also termed oxygen uptake) by polymers during degradation. 63 Oxygen uptake can be measured in various ways 64 such as measuring volume change, 65 mass spectroscopy, 66,67 thermal treatment, measuring oxidation product concentrations, 68 and ultraviolet microscopy. 69 Optical chemical sensing of oxygen represents a straightforward way to measure oxygen consumption in polymers because phosphorescent oxygen indicators are known to be efficient sensitizers of singlet oxygen.…”

Mn2Al-LDH- and Co2Al-LDH-stearate as photodegradants for LDPE film

“…Unfortunately, the heterogeneous nature of photodegradation complicates the determination of the applicable rate constants in the weathering of bulk polymer samples [73][74][75]. The progression of polymer degradation can be followed various chemical, physical and mechanical methods [24,71] including differential scanning calorimetry (DSC), thermogravimetric analysis (TG) [20], gel permeation chromatography (GPC) [76,77], X-ray photo-electron spectroscopy (XPS), chemiluminescence (CL) [78], Fourier transform infrared spectroscopy (FTIR) [26,79], oxygen uptake [80], CO 2 evolution studies [81,82] and mechanical testing [24,26,83]. FTIR is widely used to follow the time evolution of changes in the functional groups present [79].…”

Ageing of PCCD aliphatic polyesters: Effect of stereochemistry and ionic chain terminals

“…Indeed, photooxidation of PCCD films leads to significant changes in the IR absorption spectra in these two zones. Evolution of the absorption band centred at 1710 cm −1 results in a sensitive parameter, quantitatively related to the amount of oxidation [37]. However, the high content of ester groups in the polymer backbone rather overrides changes in IR spectra at 1710 cm −1 upon oxidation.…”