IR spectroscopy research of the influence of UV radiation on stabilized polyethylene composites

Abstract The paper presents the results of the IR spectroscopy study of the effect of UV radiation on polyethylene composites containing various climatic stabilizers. These composites are used for storage and transportation of hydrocarbon materials to remote areas of the Republic of Sakha (Yakutia), in which where are both large fluctuations in average annual temperature and a high level of solar radiation. It was found that UV radiation affecting the surface of the composites produces radical reactions with the formation of oxidized products, as well as unsaturated bonds. The following products were detected: carboxylic acids, esters, aldehydes, and compounds containing vinylene and vinylidene groups. It was shown that the number of vinyl groups after irradiation decreases. It has been suggested that a high concentration of vinylidene groups may indicate the effectiveness of the stabilizer against UV radiation. From the comparison of the obtained results with the studies of the features of polyethylene aging under UV radiation described by other authors, it was observed that there is a frequency shift corresponding to the fluctuation of the vinylidene group, which may indicate the formation of cyclic structures. Besides, it was shown that the results are in good agreement with the data obtained during long-term climatic tests of similar composites described in a previous publication by the authors.