PACKAGING | BIO-BASED MATERIALS
Above: Julia Curley founded EsterCycle, based in Colorado, USA, which uses a process with a solvent and catalyst to break down polyester-based plastics to their fundamental building blocks
leaked to the environment, and is easily recyclable,” said Amazon’s Director of Materials and Energy Sciences, Alan Jacobsen, in an interview with Compounding World. He pointed out that, currently, paper packaging can have these attributes and many conventional plastic packages do not. Jacobsen added, how- ever, that plastic has its advantages over paper, such as allowing thinner and lighter-weight packaging that can lower carbon footprint, and offers better barrier properties and moisture resistance, for example. Amazon’s long-term objective is to create and use plastics that retain these benefits while also being bio-based, biode- gradable, and easily recyclable. How compostability and recyclability can be made compatible is a complex question. Non-com- postable packaging is a contaminant for compost- ers, and recyclers may be concerned that com- postable packaging could be a detriment in their feedstreams. Amazon, however, is looking ahead to a future vision of a fundamentally different way of using materials in packaging. “Today, people in the industry see a dichotomy between recyclability and compostability, but we would really like to have both simultaneously,” said Jacobsen. Although technology limitations on sorting, separating, and recycling are currently barriers, Amazon is investing in development to achieve this goal, with two projects focused on recycling of biodegradable plastics.
Depolymerisation The term “recycling” can encompass more than mechanical recycling; chemical recycling is also being considered as a way to create circularity for plastic materials. Amazon envisions a packaging
34 PLASTICS RECYCLING WORLD | May/June 2025
waste stream composed of mixed, polyester-type bio-based plastics (eg PLA, PBAT, and others) that are compostable under specific conditions and can alternatively be recycled using depolymerisation. To that end, the company joined a consortium called Bio-Optimised Technologies to keep Thermoplas- tics out of Landfills and the Environment (BOTTLE), led by the US Department of Energy’s National Renewable Energy Laboratory (NREL). In NREL’s lab, the BOTTLE consortium worked on developing energy-efficient, low-temperature chemical processes to deconstruct mixed polyes- ter-type plastic waste into intermediate chemicals that can be used to make either the same or new types of plastics, without the degradation of properties that can occur with mechanical recy- cling. As a result, Julia Curley, who was part of the team that helped develop the technology, created EsterCycle, a Colorado, USA-based start-up focused on recycling plastics. In a follow-up project, Amazon is collaborating with EsterCycle. EsterCycle uses a catalyst and a methanol solvent to break down mixed polyester plastics to its building blocks, which are then separated and purified. The process is reported to be tolerant to a range of contaminants and additives typically found in post-consumer recycled (PCR) plastic. Next steps for the start-up are to scale up from the lab and build a pilot plant.
Sorting with AI The feedstock for the EsterCycle process could be bales of mixed polyester-type PCR collected by materials recovery facilities (MRFs). To tackle this piece of the puzzle, Amazon has invested in San Francisco, CA, USA-based start-up Glacier, which was founded to develop cost-effective, robotic automation systems for MRFs. Glacier is building an artificial intelligence-enabled detection and
Mixed polyester recycling study
Researchers in the BOTTLE consortium recently published a techno-economic analysis and lifecycle assessment comparing polyester depolymerisation techniques for feedstock containing PET, PLA, and PBAT. The analysis concluded that methanolysis has lower cost and environmental impacts compared to glycolysis and hydrolysis. The researchers suggested that a mixed polyester recycling process could enable circularity. Reference: DesVeaux, Jason S. et al. One Earth, Volume 7, Issue 12, 2204 – 2222.
www.plasticsrecyclingworld.com
IMAGE: ESTERCYCLE
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