Strategies for Designing Circular, Sustainable, and Nonpersistent Consumer Plastic Products: A Case Study of Drinking Straws.

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.