Polaris Renewables is developing renewable non-isocyanate polyurethanes (NIPUs) for use in foams, coatings, and synthetic leathers. Philip Pienkos, founder and CEO, and Ben Galphin, business development advisor, explain more to Jessica Owen.
Conventional polyurethanes have been around since the 1950s. They can be tailored to be either rigid or flexible, and they can be used for a broad range of applications such as car parts, insulation, shoe soles, or coatings.
To make polyurethane, the chemistry involves reacting a class of chemicals called polyols with another class of chemicals called isocyanates. And then, depending on the application, custom formulas can be made by adding other elements such as catalysts (to control the speed of the reaction), adhesion promoters (to determine stickiness), and blowing agents (to determine the density and foaming action).
Because polyurethanes are so versatile, the market has grown immensely, however the isocyanates used to make them are ‘remarkably toxic’ and have been found to affect human health by causing dermatitis and occupational asthma, for example. With that in mind, there is now a desire across the industry to replace isocyanates with safer and more sustainable substitutes, which is what the team at Polaris Renewables is exploring.
“The desire to make biobased polyurethanes has been growing since the beginning of the 21st century,” says Philip Pienkos, founder and CEO, Polaris Renewables.
“Someone did identify the potential to produce polyols from vegetable oils, but isocyanates were still required. And so, we took this as a jumping off place and have now developed an entirely different chemistry that eliminates isocyanates to fully renewable non-isocyanate polyurethanes (NIPUs).”
To make the NIPUs, Polaris Renewables is taking advantage of oils that come from renewable sources such as soybeans, linseed, algae, and waste. Useful oils contain fatty acids. As long as the lipid molecules contain two or more double bonds per lipid molecules. These double bonds are vital for the process to work because they can react with hydrogen peroxide to form an epoxy ring-like structure.
“To make conventional polyurethane with isocyanate, the chemists would open this ring structure to make the polyols, and these would then be reacted with the isocyanates,” Pienkos explains. “But what we do is react the epoxy ring with carbon dioxide to form a carbonate ring instead.
“Now, this carbonate ring can react with a class of molecules called polyamines, which can also be produced from renewable resources. These polyamines act as crosslinkers that react with the carbonate rings, and this finally forms the polyurethane structure.”
By sequestering and using carbon dioxide instead, the team has calculated that the carbon footprint of the NIPU is as much as 63% lower than that of isocyanate-based polyurethanes. The reason being that not only is the isocyanate being eliminated, but the carbon dioxide capture means that 30% less of the other materials are needed to make one tonne of the polymer.
“And so, it’s not only the amount of CO2 that's captured into the molecule, but less of the other monomers are needed and actually this has a bigger impact on the overall carbon footprint,” says Pienkos.
As you can see, this is a very complex process, but Pienkos has been working on the concept for some time. In fact, he got the idea for developing NIPUs when he was working at the National Renewable Energy Laboratory (NREL) in Colorado, US. At the time, he was leading a biofuels project when the subject came onto his radar. He initiated a research proposal with some colleagues to explore the idea and managed to generate some intellectual property. Pienkos then retired in March 2020, and instead of putting his feet up, he officially incorporated Polaris Renewables company one month later in April to commercialise the technology.
“I decided that the technology for the NIPU was just so interesting and exciting that it had to be the next step in my career,” he says.
At the moment, Polaris Renewables is at the beginning of its ‘growth phase’ and it is still involved with NREL. However, Pienkos has already brought on board Ben Galphin (business development advisor) who has previously worked for Patagonia and has a consulting company called Outsider Innovation, in addition to the company’s co-founder, Tao Dong. Dong worked with Pienkos at NREL and co-invented technologies to produce NIPUs.
Moving forward, the company has defined three key application areas that it wants to explore: synthetic leathers, foams, and coatings.
“There’s a lot of attention on synthetic leathers right now with companies such as Modern Meadow and Miko,” says Galphin.
“Today, the largest share of the synthetic leather market is held by polyurethane, which is applied to a textile carrier and then finished. But to have something that’s potentially completely renewable and biodegradable would allow us to capture that market.
“There is also a huge place for biobased foams that could be used to manufacture footwear. Companies such as Allbirds and Nike are already exploring that and so there is a lot of opportunity here. Finally, I think coatings such as waterproofing is a big one. The chemistry can be really tricky, but it’s a tertiary market that we’d like to explore.”
To add to that, Pienkos says that the great thing about NIPUs is that they can be tweaked to suit different applications, thanks to the decades of knowledge and research that has been acquired developing conventional polyurethanes. This means that Polaris Renewables can ‘drill down and focus’ on what the earliest entry into the market will be based on the state of the technology and needs of potential customers.
“My goal is to have a minimum viable prototype by the end of 2022,” he says.
Once the team has its prototypes, it hopes that scaling up will be relatively straightforward because it has developed it to be a ‘plug and play’ solution. Feedstock such as the linseed oil is already commercially available at scale, and the polymer chemistry has been designed to replace existing polyurethane infrastructure, so rather than building a grassroots manufacturing facility, it can slot into the existing process.
“For many companies, this will be the easiest route into the door,” Galphin explains. “And then we can work on specific formulations to address the problems they didn't know they had.”
Another attractive aspect is the price. Polaris Renewables reckons that it can produce material for around US$2 per pound – an amount that won’t cause the fashion industry heartburn.
“You know, no one else is commercialising a technology like this. There’s lots of potential. And I have the sense that this potential starts with us and our small niche market, but that it will grow beyond that – which I find very, very exciting,” Pienkos concludes.
To find out more about Polaris Renewables, visit https//polarisrenewables.com
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