Investigating the Aging Mechanisms of Polyethylene Under Numerous Actions Produced by Non-Thermal Plasma

Polymer materials are widely used in a variety of applications in everyday life because they are lightweight, chemically and physically stable, inexpensive, and easy to mold. Polymer materials in nature are susceptible to external reactions such as ultraviolet (UV), biological, thermal, and mechanical stress. The aging mechanism of polymer materials is crucial since these degradation factors age polymer materials and reduce their performance. However, due to polymer aging behavior in complex natural conditions and a relatively slow aging process, it is difficult to identify polymer aging mechanisms. Here, to clarify the aging process of polyethylene (PE), non-thermal plasma was used to simulate considering the various aging factors such as UV, reactive oxygen species (ROS), thermal, and mechanical stress that occur in nature. As a result, a phenomenon similar to long-term aging appeared even with a short treatment time of less than 1 hour, and the effects of various degradation factors were comprehensively considered. As aging progressed, the existing hydrocarbon chain bonds were cleaved, oxygen-containing functional groups were confirmed to form, and the carbonyl index increased. Furthermore, when comparing the final by-product to the traditional degradation mechanism, it was found that the same functional groups were generated. Our findings may help researchers better understand the PE aging mechanism, study the prevention of PE degradation, and even provide useful information for studying effective degradation.