Kinetic Features of the Oxidative Destruction of Polyethylene with Addition of Stearates of Various Transition Metals

In this work, the ability of calcium, magnesium, and zinc stearates to oxidative destruction of polyethylene was studied. For comparison, the samples of pure polyethylene and polyethylene with the commercial additive D₂W were selected. Infrared spectroscopy data showed that samples with magnesium stearate accumulated double carbon bonds after 96 h of exposure in a climate chamber. In samples with zinc stearate, an asymmetric vibrations of COO groups disappear after 192 h of exposure in a climate chamber. All samples accumulated carbonyl groups resulting from polymer chain scission. After 96 h of aging, the sample with calcium stearate showed better oxidizing properties compared to other stearates. Mechanical test data also confirms the conclusion that the sample with calcium stearate is more susceptible to oxidative degradation among the studied stearates.