UT Dallas researchers created a durable, self-repairing, and more recyclable 3D-printed foam using dynamic chemistry, opening new possibilities for sustainable manufacturing.
From seat cushions to mattresses to insulation, foam is everywhere — even if we don’t always notice it.
Now, researchers at The University of Texas at Dallas have combined chemistry and advanced manufacturing to develop a new type of 3D-printed foam that is both more durable and more recyclable than conventional polymer foams.
The study, published in the March 1 print edition of RSC Applied Polymers, a journal of the Royal Society of Chemistry, aimed to create a strong yet lightweight foam suitable for 3D printing—a technique that remains relatively untapped in large-scale manufacturing. According to co-lead author Rebecca Johnson BS’20, a doctoral student at UT Dallas, this research opens new possibilities for sustainable and customizable foam production.
“This is probably the longest project I’ve ever done,” said Johnson, who plans to complete her PhD in chemistry in May. “From start to finish, it was a little over two years. A lot of it was trying to get the polymer formulation correct to be compatible with the 3D printer.”
Although making new materials that are compatible with 3D technology is challenging, Johnson said, the 3D-printing process allowed the researchers to create complex shapes that could be customized in manufacturing applications. To demonstrate the proof-of-concept, they produced foam in the shape of a balloon dog.
Innovative Foam for Impact and Insulation
“The goal of the project was to address some limitations in 3D printing in terms of making polymer foam,” said Dr. Ron Smaldone, associate professor of chemistry and biochemistry in the School of Natural Sciences and Mathematics and the corresponding author of the study. “One of the main uses, or interests, for 3D-printable foams is insulation and shock absorption.”
With more research and experimentation, Smaldone said, this type of foam and process could be used for high-impact absorption items such as motorcycle or football helmets, car bumpers, or armor. He also noted that 3D printing enables the creation of more complex structures, such as fine lattices, which can increase the physical flexibility of the material and provide more versatility for applications.
The authors discuss their research. Credit: Royal Society Of Chemistry
The researchers also examined how to make a material that could be 3D-printed into a consistent final product without a lot of defects. Most commercial foam is thermoset, meaning it undergoes a chemical reaction during molding that permanently locks its structure in place, preventing it from being reshaped, melted,d or dissolved. As a result, most polymer foam cannot be recycled and ultimately ends up in landfills, Smaldone said.
The UT Dallas researchers developed their durable foam using special reversible bonds, called dynamic covalent chemistry. Although the foam cannot be completely melted and reshaped like plastic, these bonds allow the material to repair itself when damaged, making it more versatile and longer lasting.
Toward Greater Sustainability
“We’re certainly not the only ones trying to do this,” Smaldone said. “The novelty is using dynamic chemistry to print really great foam material. The next question to address will be, how do we tune the properties and use this new kind of knowledge to fit a variety of different needs?”
Johnson and the study’s other co-lead author, chemistry doctoral student Ariel Tolfree BS’23, developed their ideas after studying similar research in the field. Tolfree, who credits Johnson as her mentor, plans to expand on the research by examining how to make the foam more recyclable and exploring the foam’s sustainability potential.
Tolfree said creating a foam balloon dog as one of the group’s test objects was a natural choice.
“It’s a simple shape but perfectly represents our foams,” Tolfree said. “A balloon seems ordinary until it’s twisted into something new, almost defying expectations. Our foams are the same — unassuming at first, but once expanded and transformed, they become something remarkable.”
Reference: “3D printable polymer foams with tunable expansion and mechanical properties enabled by catalyst-free dynamic covalent chemistry” by Rebecca M. Johnson, Ariel R. Tolfree, Gustavo Felicio Perruci, Lyndsay C. Ayers, Niyati Arora, Emma E. Liu, Vijayalakshmi Ganesh, Hongbing Lu and Ronald A. Smaldone, 28 January 2025, RSC Applied Polymers.
DOI: 10.1039/D4LP00374H
Additional UT Dallas co-authors of the study are mechanical engineering doctoral student Gustavo Felicio Perruci; chemistry doctoral students Lyndsay Ayers BS’24 and Niyati Arora; chemistry senior Emma Liu; Vijayalakshmi Ganesh BS’23; and Dr. Hongbing Lu, professor of mechanical engineering and the Louis Beecherl Jr. Chair in the Erik Jonsson School of Engineering and Computer Science.
The research was funded by The Welch Foundation, the National Science Foundation (2323729, 2219347), and the Department of Energy (DE-NA0003962, DE-EE0011016, DE-EE0010200).
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