Researchers from Colorado State University have created an adhesive polymer that is both biodegradable and reusable, and it is stronger than the ones that are currently on the market. The results, which were published in Science, demonstrate how the common, naturally occurring polymer P3HB can be chemically redesigned to function as a powerful yet long-lasting bonding agent.
A weight system to visualize the adhesive strength of the new biodegradable adhesive polymer. Image Credit: Colorado State University
Among many other industries, adhesives are frequently utilized in solar cells, electronics, packaging, automobiles, and construction. Together, they comprise an industry worth about $50 billion that sustains a large portion of contemporary lives while also adding to the growing problem of plastic waste. The team's efforts to create a replacement polymer through process modeling, simulation, and experimentation are detailed in the research.
Eugene Chen, a University Distinguished Professor in the Chemistry Department, oversaw the project. Gregg Beckham from the National Renewable Energy Laboratory, Professor Ting Xu from the University of California, Berkeley, and researchers from their respective teams are additional collaborators on the study.
According to Chen, microbes can produce poly(3-hydroxybutyrate), or P3HB, a natural, biobased, and biodegradable polymer, given the correct biological conditions.
Although the polymer is not adhesive in its original form, his lab successfully re-engineered its structure to provide stronger adhesion than common petroleum-derived, non-biodegradable alternatives when applied to various substrates such as aluminum, glass, and wood. Additionally, the re-engineered P3HB's adhesion strength can be adjusted to meet the requirements of various applications.
The findings contribute to Chen's broader objective of enhancing and expanding efforts to address the global plastics pollution crisis. His group is working on numerous projects to create biodegradable, chemically recyclable, and generally more sustainable substitutes for today's plastics.
According to him, adhesives pose more difficult problems with fewer possible fixes, even though many people are naturally aware of the life cycle problems associated with disposable water bottles.
“Petroleum-based thermoset adhesives such as Gorilla Glue and J-B Weld, along with thermoplastic hot melts, can be very difficult or even impossible to recycle or recover – primarily because of their strong bonds to other materials. Our approach instead offers a biodegradable material that can be used in a variety of industries with tunable or even higher strength compared to those options,” he noted.
Ethan Quinn, a Ph.D. candidate at CSU, Co-Authored the paper with Zhen Zhang, a Postdoctoral Researcher. Quinn stated that he and Zhang oversaw the development and testing of the material.
We developed a sample P3HB glue stick and were able to use it with a commercially available glue gun to test its application in sealing cardboard boxes and other properties on steel plates. I knew the data supported it being stronger than other options, but I was shocked that we were able to show that it far out-performs typical hot-melt options – holding up to 20 pounds in place compared to the 15 pounds an existing adhesive could not manage.
Ethan Quinn, Ph.D. Candidate, Colorado State University
According to Chen, the biodegradability of P3HB can occur in both managed and unmanaged environments. This implies that it will naturally biodegrade in landfills just as effectively as salty soils or ocean water.
This increases the number of options available for handling the material at the end of its life cycle. Additionally, the P3HB adhesive is recoverable, reprocessable, and reusable.
The CSU team will begin developing strategies for commercializing the polymer for widespread application.
We are working on two different approaches aiming for mass production, including ways to lower the overall cost and environmental impacts. The analysis performed by the NREL team has identified key areas where we could make improvements, and we will continue to work with the BOTTLE Consortium on those scaling efforts.
Eugene Chen, Distinguished Professor, Colorado State University
The research done at CSU and NREL was funded by the Department of Energy’s BOTTLE Consortium.
Journal Reference:
Zhang, Z., et al. (2025) Stereomicrostructure-regulated biodegradable adhesives. Science. doi.org/10.1126/science.adr7175.