Consumer Gatekeeping in Sustainable Materials Streams—An Application in Cellulose Nanomaterials

U.S. consumers spent 4.5 trillion dollars on goods while generating 292 million tons of municipal solid waste in 2018 – and trends in both spending and waste generation are increasing. Packaging and containers made of paper and paperboard (6.4 million tons) and plastic (10 million tons) are the greatest proportion of landfilled tonnage. Displacing plastic-based materials with bio-sourced materials may be consistent with green chemistry and engineering design principles but does not truly improve the circular economy if the bio-sourced materials travel straight to landfill. Consumers act as gatekeepers in a circular economy, determining which products and materials end up in landfill or are diverted back to post-consumer manufacturers. By understanding consumer behaviors around product acquisition and disposition, products can be manufactured to ensure that the value of materials is retained.<br/>Here we develop a framework for incorporating consumer behavior into circular economy. We advance the green chemistry principle of F-factor by incorporating manufacturing efficiency and consumer behavior into the lifetime functionality of material mass. We demonstrate the framework using cellulose nanomaterials (CNMs) in packaging – a new bio-based material with the dual potential to be a “good citizen” in landfill and to contribute to post-consumer product manufacturing. The framework highlights how increased functionality, and thus the preservation of economic value, arises from the recirculation of material streams that pass through multiple sequential phases: from the manufacturing phase – where green chemistry principles can be applied - to product acquisition - where manufacturing decisions meet consumer decision-making – to product disposition – where consumer behavior dominates – and back to manufacturing. This approach reassesses the impact of sustainable manufacturing practices and showcases new strategic opportunities for high-impact policy interventions – targeting both manufacturers and consumers – to reduce wasted resources and improve the circularity of <i>function</i>.