Strategies for Designing “Green” Plastic Products
ChE Assistant Professor Bryan James, alongside Collin Ward, Yanchen Sun, Brenden Irving, and Kali Pate from Woods Hole Oceanographic Institution, published their research on “Strategies for designing circular, sustainable, and non-persistent consumer plastic products: a case study of drinking straws” in Environmental Science & Technology.
Since graduate school, James has asked, “What’s the best straw for people and the planet?” Given the prevalence of plastic drinking straw bans and even a presidential executive order weighing in on the issue, someone needed to provide some clarity to this simple yet complex question. His latest work helps to answer that question.
In the study, James and his colleagues investigated thirteen drinking straws found on-the-market, evaluating them for their renewability, resource utilization, climate change impact, end-of-life disposal, and persistence in the ocean. Taking this approach, the team arrived at four key conclusions that can be applied to designing future plastic products,
- Using captured methane (a potent greenhouse gas) can result in products with a lifetime net-negative global warming potential,
- Including biomass in conventional commodity plastics is unlikely to result in substantial environmental benefits,
- Many marketing claims regarding sustainability and environmental impacts are unsupported, and
- Disposing of compostable plastics in a landfill could increase the global warming potential of the item, offsetting many of the advantages of the biodegradable material.
To remedy the issue of marketing claims, James proposes the adoption of a standardized “nutrition facts” type label for the sustainability and environmental impacts of products to support decision-making, so that consumers and policymakers can better evaluate products. The article encourages consumers, brands, and policymakers to support efforts for the proper disposal of compostable products by enhancing consumer education and supporting investment in industrial and home composting facilities. Ultimately, this case study of drinking straws revealed commercially viable and scalable design strategies and their tradeoffs that can be applied broadly when developing and adopting future consumer plastic products.
Abstract:
Drinking straws present a simple form factor for evaluating material design strategies taken by manufacturers to achieve circular, sustainable, and nonpersistent products in response to global restrictions and consumer sentiment. We investigated 13 on-the-market drinking straws of varying formulations, characterizing their physical, chemical, and marine biodegradation properties. These data informed sustainability metrics used for evaluating the effectiveness and trade-offs of design strategies, ultimately arriving at four key conclusions. First, diverting anthropogenic methane as an alternative feedstock to make polyhydroxyalkanoates (PHAs) resulted in the only straw with a net-negative global warming potential. Second, adding biogenic fillers to conventional polymers (e.g., polypropylene) to minimize plastic usage is unlikely to produce substantial environmental benefits compared to using alternative polymers. Third, many marketing claims about circularity, sustainability, and persistence were unsupported, likely magnifying the mismanagement and environmental impacts of these products. Fourth, improper disposal of compostable straws in landfills could increase the global warming potential of the item by up to 6 times and offset numerous advantages afforded by biodegradable materials, thereby warranting greater investment in waste management infrastructure. The analysis of design strategies and their trade-offs provided herein should be applied broadly when developing and adopting future consumer products.
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