Comparative life cycle assessment study of virgin polyethylene and bio-polyethylene, with recycled polyethylene from uncontaminated post-industrial film

Abstract

Petroleum-derived plastics are widely used but rely on non-renewable resources and contribute to environmental degradation during production. Recycling and the adoption of bio-based plastics offer potential solutions within the framework of green chemistry. However, it is essential to evaluate their relative environmental impacts to avoid burden-shifting within the supply chain. This study conducts a life cycle assessment (LCA) comparing three alternatives for plastic shopping bag production in Japan: virgin polyethylene (PE), bio-based PE, and mechanically recycled PE (Repla™) derived from uncontaminated post-industrial film. The recycled Repla™ material, which would otherwise be incinerated, demonstrated significantly lower CO₂ emissions. While recycled materials often outperform virgin plastics, Repla™ also showed lower impacts than bio-PE. This is largely due to the use of fossil fuels in bio-PE production. Even when substituting fossil energy with alternatives such as bagasse or waste plastic, the recycled option retained its environmental advantage. This study highlights that under realistic technological and policy scenarios, mechanical recycling using clean post-industrial waste can deliver superior environmental benefits, underscoring its value as a green chemistry solution.