Long-term stability of recycled low-density polyethylene (LDPE) films under photo-oxidative aging

The use of post-consumer recycled low-density polyethylene (LDPE) in outdoor applications is still limited by concerns related to its resistance to photo-oxidative degradation and this issue is particularly relevant for applications exposed to UV radiation, where material degradation can lead to a progressive loss of structural and functional properties.

This work focuses on the evaluation of the durability of a recycled LDPE film intended for outdoor applications under accelerated photoaging. In particular, the aim is to investigate the effectiveness of a conventional stabilization strategy commonly adopted for virgin LDPE films, based on the addition of a hindered phenolic antioxidant, when applied to post-consumer recycled LDPE. Although the stabilizing effect of these additives on virgin LDPE films has been widely investigated in the literature, fewer data are currently available regarding their efficiency in recycled LDPE matrices.

For this purpose, a stabilized recycled LDPE film was compared with the corresponding virgin LDPE film during photoaging. The aging process was monitored through different characterization techniques, including spectroscopic analysis, thermal tests, mechanical characterization and rheological assessment, in order to obtain a comprehensive evaluation of the chemical, structural and functional degradation induced by photo-oxidation.

The results obtained during the aging process highlighted that the recycled product was able to maintain its primary function under the investigated conditions. In particular, the properties of the stabilized recycled LDPE film remained suitable and comparable to those of the virgin LDPE film, indicating that the adopted stabilization strategy is effective also for recycled LDPE.

Overall, this work shows that properly stabilized post-consumer recycled LDPE can represent a promising alternative to virgin LDPE for applications requiring resistance to photoaging, promoting material reuse without compromising essential performance requirements.