We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Differences in the Residual Behavior of a Bumetrizole-Type Ultraviolet Light Absorber during the Degradation of Various Polymers
Summary
Researchers tracked how a UV-stabilizing chemical additive (UV-326) leaches out of five different plastics — PP, HDPE, LDPE, PLA, and PS — as they degrade in seawater, finding that the release rate depends on the polymer's structure and glass transition temperature. PS retained the additive longest due to its higher glass transition temperature, while crystalline polymers behaved similarly to one another. Because UV absorbers are toxic and persist in the environment, understanding how quickly they escape from degrading plastic fragments (microplastics) is important for assessing the chemical hazard posed by plastic pollution in marine environments.
The alteration of an ultraviolet light absorber (UVA: UV-326) in polymers (PP, HDPE, LDPE, PLA, and PS) over time during degradation was studied using an enhanced degradation method (EDM) involving sulfate ion radicals in seawater. The EDM was employed to homogeneously degrade the entire polymer samples containing the UVA. The PP and PS samples containing 5-phr (phr: per hundred resin) UVA films underwent rapid whitening, characterized by the formation of numerous grooves or crushed particles. Notably, the UVA loss rate in PS, with the higher glass transition temperature (Tg), was considerably slower. The behavior of crystalline polymers, with the exception of PS, was analogous in terms of the change in UVA loss rate over the course of degradation. The significant increase in the initial loss rate observed during EDM degradation was due to microplasticization. A similar increase in microplasticization rate occurred with PS; however, the intermolecular interaction between UVA and PS did not result in as pronounced an increase in loss rate as observed in other polymers. Importantly, the chemical structure of UVA remained unaltered during EDM degradation. These findings revealed that the primary cause of UVA loss was leaching from the polymer matrix.