Sunlight and marine weathering of poly(oxymethylene): Evolution of the physico-chemical properties

Plastic pollution is now an environmental problem that affects all environmental compartments. The study of plastic degradation in terrestrial, marine and other freshwater environments is emerging. Research is mainly focused on plastic fragmentation into microplastics. In this contribution, an engineering polymer, poly(oxy-methylene) (POM), was studied under different weathering conditions using physico-chemical characterization techniques. A POM homopolymer and a POM copolymer were characterized by electron microscopy, tensile tests, DSC, infrared spectroscopy and rheometry tests after climatic and marine weathering or artificial UV/water spray cycles. Natural climatic conditions were the most favorable for POM degradation, especially under solar UV, as evidenced by the strong fragmentation into microplastics when subjected to artificial UV cycles. The evolution of properties with exposure time was found to be non-linear under natural conditions, in contrast to artificial conditions. Two main stages of degradation were evidenced by the correlation between strain at break and carbonyl indices.

Automated summary

Plastic pollution is a widespread environmental problem that affects various natural habitats. Recently, there has been a growing interest in studying the degradation of plastics in terrestrial, marine, and freshwater environments, with a focus on the fragmentation of plastics into microplastics. This study investigated the degradation of a specific type of engineering polymer, poly(oxy-methylene), under different weathering conditions, using various characterization techniques. The results revealed that natural climatic conditions, especially solar UV radiation, were the most favorable for the degradation of the polymer, leading to significant fragmentation into microplastics.