The ocean plastic issue has caught its share of media attention, and rightfully so. However, there are other pressing issues related to the overflow of petrochemical-derived waste. One of them is how to recycle the mountains of polyurethane foam that are burned or disposed in landfills every year.
Sheer bulk is one part of the problem. In its flexible form, polyurethane foam is commonly used in large-scale applications including automobile interiors, carpet underlay, mattresses, acoustic foam and many other types of cushions. Rigid forms of the foam are also popular in the construction industry, with building insulation a primary use.
Though many of these items are long-lasting, eventually the foam becomes waste. As of 2012, the U.S. alone generated an estimated 1.3 million tons of polyurethane foam waste.
Unfortunately, so far foam has resisted recycling efforts. Polyurethane foam is made from crude oil, like other plastics. However, it is produced through a cross-chemistry process that makes it resistant to melting and reformation.
For the most part, recycling options are limited to shredding. The primary use for recycled polyurethane fiber today is in carpeting.
Otherwise, the only other options are to downcycle it and burn it as fuel or dispose it in a landfill.
If foam could be upcycled into higher value products, that would provide a financial basis for recovering and recycling more foam waste.
The key technology challenge for expanding the range of applications for recycled foam is dealing with the air trapped within its structure, and a team of researchers at Northwestern University in Illinois may have discovered an economical solution.
Their approach is similar to pushing a large sponge through a Play-Doh extruder. It can be done, but first the nature of the sponge needs to change.
One method would be to compress or slice the sponge, but the result would be a brittle material that is difficult to mold into new shapes without further treatment.
The process that Northwestern developed resolves those problems with a two-step system. First, the foam is softened with a commonly used catalyst called dibutyltin dilaurate, a colorless, oily liquid that is sometimes added to animal feed as a treatment for worms and other parasites.
The catalyst reduces the foam to a less spongy consistency. Then it can be extruded through a specially designed device. Two rotating, intermeshing screws in the device remove the air while improving the consistency of the reduced foam.
The result is a new material that can be upcycled to various forms including hard plastic and flexible film.
Northwestern cites shoe cushions, accessories (watch bands, for example), hard wheels (as in skateboards and shopping carts) and auto parts as potential uses.
The Northwestern recycling research is one part of the effort to reduce the use of virgin crude oil in plastic products.
Another approach is to reduce the use of crude oil in making the foam itself.
Researchers are experimenting with various sustainable alternatives including walnut shells, fossilized algae, and even sugar to achieve an alternative material that meets the performance standards of conventional foam.
Meanwhile, interest in reclaiming and recovering plastic waste from the ocean has continued to grow, despite the global economic crisis touched off by the COVID-19 crisis.
One recent example is last month’s ocean plastic announcement from Japan-based JSP. The company has introduced a new product called Apro 35, made with 15 percent maritime waste, from recovered fishing nets and other gear.
Recycling also provides a financial incentive for keeping maritime waste out of the ocean in the first place. In one significant development, last month the third-party certification firm UL validated recycled content for five resins used by HP, ranging from 5 percent to 99 percent “ocean-bound” plastic.
The “bound” refers to plastic at risk of entering the ocean. This is the first time that UL has provided validation through an upgraded recycling standard that includes measuring the impact of collecting recycled materials on local economies. Now that HP is on board, other major resin users may strive to achieve validation as well.
As the world recovers from the COVID-19 crisis, companies like these are laying the groundwork for an economic recovery that finds solutions to environmental problems instead of causing them.
Image credit: Pixabay
Tina writes frequently for TriplePundit and other websites, with a focus on military, government and corporate sustainability, clean tech research and emerging energy technologies. She is a former Deputy Director of Public Affairs of the New York City Department of Environmental Protection, and author of books and articles on recycling and other conservation themes.
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