Extended Additives’ Performance in Polyethylene Thin Films

For several decades additives have been incorporated into polymeric systems to improve desirable properties, and eliminate undesirable properties. When added to a polyethylene film, the additives migrate to the films’ surface and their concentration decreases; over time the additive’s effect desists. To solve this problem, efficient methods for extended performance are being sought. Extended additives’ performance is necessary to avoid frequent substitution of polyethylene films for different applications (e.g. greenhouses plastic coverings); as a result, reducing plastic waste and contributing to environmental sustainability. Over the course of our work, a new method of additives’ controlled migration has been developed, by grafting the additive molecules to nano-particles (NPs) via a radical reaction. The particles were used as physical migration retarders. Nano-particles were chosen due to their small size, which does not scatter light significantly. It was thus possible to make composites that retain their optical clarity. Furthermore, the small size of the particles leads to a large interfacial area for grafting. This work focuses on additives such as antifogs (AF) and UV protecting agents. The NPs serve as physical migration retarders, as well as UV protecting agents; the organic grafted molecules serve as AF additives. The existence of the grafted AF molecules to the NP’s surfaces was confirmed; the polyethylene containing AF grafted particles (LLDPE/AF-NPs) has shown satisfactory and promising AF and UV protection performance.