Degradable Plastics 3D-printed Using Salt

By James Anderson •  Updated: 10/31/22 •  3 min read

The majority of synthetic commercial polymers are made up of large molecules and are stable most of the time. While manufactured items like Styrofoam cups or plastic containers degrade into minute fragments that are invisible to the naked eye when left in the environment, the long polymer molecules are always present.

Dr. Emily Pentzer is an associate professor in the Departments of Chemistry and Materials Science and Engineering at Texas A&M University. She is working to make 3D-printed polymers last longer by letting them break down on their own over time.

“Our goal was to create sustainable degradable polymeric structures. We did this by leveraging the microstructures afforded by chemistry in conjunction with the macrostructures afforded by 3D printing,”

Pentzer said.

Tiny Pores Help Degrading Process

3d printed polymers degradable salt

Degradable CO2-based triblock polycarbonates with tailored thermal and mechanical properties were synthesized via a one-pot, two-step strategy. Credit: Texas A&M Engineering

Pentzer worked in partnership with Dr. Don Darensbourg, a professor in Texas A&M’s Department of Chemistry, to create the degradable polymers by combining table salt and carbon dioxide to make the ink for the 3D printing process.

The structures are washed in water after printing to remove the salt and solidify them. Thousands of tiny pores are formed during the process, which allows chemical compounds to break down more quickly even though the structure’s exterior continues to look smooth.

“It’s not just the plastic bottle being kicked down the road. These materials break down into microplastics that stay in the environment. We don’t fully understand the impact of microplastics, but they’ve been shown to carry diseases, heavy metals and fecal bacteria,”

Pentzer said.

Applications Of 3D-printed Polymers

The created polymers actually degrade quickly under the right circumstances. Ideally, they will disintegrate into harmless small molecules. Heavy metals or bacteria won’t be able to travel along in these smaller molecules.

Pentzer hopes to use this process to develop packaging materials as the research advances so that items like boxes and tape can degrade quickly rather than spending a long time in a landfill. She also believes that 3D-printed polymers have a promising future in the biomedical industry.

“These materials can be used for diverse biomedical applications. Things like scaffolds for implants that will degrade over time so your body can heal, but you won’t have that piece of plastic in you forever,”

Pentzer said.

Pentzer is working to find a solution to a global issue that could affect the environment, human health, biomedicine, and nearly every facet of human existence. When science and engineering work collaboratively, they can achieve much more and create synergy, she concluded.

Reference:

P. Wei, G. A. Bhat, C. E. Cipriani, H. Mohammad, K. Schoonover, E. B. Pentzer, D. J. Darensbourg, Angew. 3D Printed CO2-Based Triblock Copolymers and Post-Printing Modification. Chem. Int. Ed. 2022, 61, e202208355; Angew. Chem. 2022, 134, e202208355.

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