Economic and Environmental Viability of Mixed Polyester Chemical Recycling for a Circular and Sustainable Plastic Economy

Biodegradable polyesters offer an attractive solution to the plastic pollution problem, as they can biodegrade in composting facilities and specific natural environments. However, these valuable materials should ideally be kept in circulation rather than permitted to degrade. While biodegradable plastics subjected to mechanical recycling often exhibit sub-optimal properties, chemical recycling techniques could potentially retain quality while keeping these materials in a circular economy. Here, we conduct a comprehensive technoeconomic analysis and life cycle assessment of three chemical recycling methods: methanolysis, glycolysis, and acid hydrolysis. Our analysis focuses on mixed polyester feedstocks containing polylactic acid (PLA), polybutylene adipate terephthalate (PBAT), and polyethylene terephthalate (PET). We demonstrate that methanolysis economically and environmentally outperforms the other chemical recycling strategies as well as virgin manufacturing of the assessed polymers. The costs and life cycle impacts of methanolysis also tend to decrease with increasing biodegradable polyester content, indicating the suitability of this technology for emerging plastic materials. We conclude by highlighting the challenges and opportunities facing chemical recycling of mixed polyesters and its role in a more sustainable, circular, and pollution-free plastics system.