The hard challenges of a soft material: Developing a circular economy for polyurethane foams
There is a good chance polyurethane foams are giving you comfort right now.
Are you sitting on an office chair? Walking around in sneakers? Scrolling through news before falling asleep on a foam mattress? That means polyurethane foam is cushioning your life.
But that comfort comes with a price: polyurethane foams — a product made from petrochemicals with an open cellular structure that holds pockets of air — is an incredibly difficult material to recycle.
A $1.8 million grant from the National Science Foundation will allow the College of Natural Resources and Environment — in collaboration with Arizona State University (ASU) and the Adidas AG corporation — to tackle these challenges using life cycle thinking. While the ASU team investigates advanced recycling technologies for polyurethane foams, the team at Virginia Tech will be mapping the presence and flows of polyurethane foams in the U.S. market and engaging with stakeholders to develop viable systems and infrastructure to recover, recycle, and redistribute these materials as part of a circular economy.
“Polyurethane foams are everywhere around us,” explained assistant professor Jennifer Russell, who teaches in the Department of Sustainable Biomaterials. “If not managed properly, particularly at end-of-life, these materials can be toxic. They are also often embedded with other materials in the finished product, making it difficult to recover, recycle, and turn into new products."
From molecules to mattresses: a challenge across scales
The impetus for this grant began with a conversation between a Hokie graduate and a faculty member.
“I was talking with a Virginia Tech alum who worked for a polyurethane foams mattress company,” explained Professor Timothy Long, center director for the Biodesign Institute at ASU and an affiliated professor with Virginia Tech’s Department of Chemistry. “He explained to me that foam mattress production is growing at an enormous rate, and that we recycle none of them. I immediately thought this would be an opportunity to make a difference. Big challenges equal big impacts.”
Long, the principal investigator for the grant, will be tasked with taking on the specific chemical challenges of reusing polyurethane.
“The challenge with polyurethane foams is that they are categorized as crosslinked, meaning that all of the molecules in that foam are essentially connected into one enormous molecule,” said Long, who taught at Virginia Tech for 20 years. “Trying to recycle that one molecule is challenging because you can’t really dissolve it and you can’t melt it. Instead, you have to do something to it chemically that brings it to a state where you can begin working with it.”
In addition to the technical challenges to recycling polyurethane foams at the molecular level, there are also systems-level challenges. To be economically viable, circular material systems require high-volumes of uncontaminated polyurethane foam products be diverted out of the waste stream – a tall task given the lack of infrastructure to support such programs.
For this project, the team is focusing on products that are largely composed of polyurethane foam (e.g., not mixed with other materials), and which can be collected in large volumes in concentrated geographic areas. The rapidly growing market for memory-foam mattresses presented just the right opportunity.
“One of the reasons that our team is focused on foam mattresses is the challenge to dispose of a large bulky mattress at the side of the road,” said Long. “In most localities, a consumer is required to dispose of a mattress at a dedicated waste depot.”
This is where Russell comes in. With more than 10 years of experience working with industries and municipal recycling programs, she is practiced at assessing the underlying infrastructure and stakeholders of product recovery systems, and finding ways to make science applicable through the co-creation of solutions and stakeholder buy-in.
“A systems-thinking approach is critical for understanding and developing solutions for the complex social-environmental-economic challenges that we are facing,” said Russell, who teaches circular economy and industrial ecology.
“One key output from this project will be a materials flow analysis that will help to clarify how polyurethane foams move through our systems, from their origins and manufacturing, through use by consumers, to the point of disposal and subsequent management in the waste stream. Where are the barriers, system-wide, that limit the capture, recycling, and reutilization of polyurethane foams?”
Russell stressed that it is important to find workable solutions for collecting polyurethane foams waste for stakeholders across urban, suburban, and rural localities. To that end, the project team will be collaborating with national nonprofit, The Recycling Partnership, as well as the Montgomery Regional Solid Waste Authority to understand the challenges of polyurethane foams collection from the New River Valley community-level, up to the national scale.
A global corporation gets their shoe in the door
Funding for the four-year grant comes from the National Science Foundation’s Emerging Frontiers in Research and Innovation program, which aims to connect innovative researchers with industry partners tackling real-world challenges. In the case of this Engineering Program GOALI grant, the industry partner is Adidas, which has a stake in improving the utilization of polyurethane products that it uses to manufacture athletic gear and apparel.
“The partnerships between universities and industry are critical for translating our laboratory success to commercial reality,” said Long. “Adidas has a sustainability mission which beautifully aligns with what we’re doing at our universities.”
Russell echoes that working with the largest shoe company in Europe offers the opportunity to effect real-world change.
“The value of having Adidas involved is that they provide a practical example of what a circular economy for polyurethane foams could look like,” Russell explained. “This is not an academic exercise: This research will lead to solutions that are designed, from the start, to be integrated into commercial business processes.”
Russell stressed that polyurethane foams, like all plastic materials, have been an important building block for decades of innovation. Better recovery and reutilization of such products and materials, even when we no longer want them, means that we can avoid having to manufacture new ones, and we can continue to rely on them down the road.
“We need to reframe what we see as waste and what we understand to be valuable,” she said. “Plastics are incredibly valuable, but they can also cause great damage to the environment and human health if we don’t manage them properly. This project is about creating systems and technology that will allow us to continue to utilize these materials responsibly and effectively.”
Written by David Fleming