Today’s trees may not only be tomorrow’s kitchen tables and plywood.
According to Clemson University researchers, they could also transform into a sustainable alternative to the foam used in car seats and in the insoles of shoes.
At Clemson University’s Center for Manufacturing Innovation, researchers met Wednesday to demonstrate how they can reconfigure lignin, a cocoa powder-like wood-processing waste product, into polyurethane foam without the use toxic chemicals.
The process usually takes about three days, according to the researchers, who have developed the method in their Greenville Clemson Composites Center lab.
The powder must be dissolved in carbonate, precipitated with acidified water and then dissolved into another carbonate. In other words, the powder becomes a cake, is then left out to dry and becomes a powder again.
Once poured into a mold with a vegetable-oil curing agent, solvent, catalyst and foaming agent concoction, the substance bubbles and rises into a disk that, once baked for 12 hours at 150 degrees, comes out at about the size of a silver dollar.
“It happens really quickly,” James Sternberg, a senior scientist on the Clemson research team, said in a news release. “You’ve got to get it all together and then take the stir bar out and put it in the oven. There is a little bit of an art to it.”
The project began its life as part of Sternberg’s dissertation when he left his job as a high school chemistry teacher four years ago to pursue a Ph.D. under Srikanth Pilla, the founding director of the Clemson Composites Center and current leader of the research group.
At the time, Sternberg’s cohorts had no idea that they would end up creating the foam, something the team calls invention nonisocyanate polyurethane foam, or NIPU foam for short.
Traditional polyurethane foams contain isocyanates, which can spur eye irritation, nasal congestion, throat soreness, cold-like symptoms, wheezing and severe asthma attacks, according to the National Institute for Occupational Safety and Health.
“The core advantage of NIPU foam is replacing the really toxic part of making polyurethanes,” Sternberg said in the release. “When you see someone spraying foam insulation in your house or spraying a polyurethane coating on something, they are in full PPE. One of those components that they are spraying is really bad for you, really toxic.”
Pilla calls the technology “truly remarkable green chemistry.”
The product is 100% biobased, he said, and has already captured the attention of several companies hoping to put it into use, as well as the U.S. Environmental Protection Agency, which awarded the team the 2021 Green Chemistry Challenge award.
The honor recognizes chemical technologies that incorporate the principles of green chemistry into chemical design and manufacturing, according to the EPA.
“This award is a reflection of the team’s vision, hard work and unwavering mission to develop a new chemistry technology that improves human health and creates a more sustainable environment,” Zoran Filipi, Clemson’s Automotive Engineering Department chair, said in the release. “This is a well-deserved honor for Dr. Pilla and his team.”
It’s his students that deserve credit for the award, Pilla adde
“People talk about Srikanth getting this award or this grant, but it’s basically these people’s work that gets us to where we are,” he said in the release. They are the pillars of my success.”As for the next step, Pilla, Sternberg and their student team are collaborating on how to tailor the product for invested manufacturers.
“Everyone wants this to work,” Sternberg said in the release. “They’ve told us, ‘This is great. We believe in it, but you have to show us how it can work for our application.”