What if the key to making stronger, more sustainable plastics isn't changing their ingredients, but rearranging their molecules?
Virginia Tech researchers have put that idea to the test, creating degradable polymers with a new molecular architecture that combines properties that are often difficult to achieve in one material: strength, toughness, flexibility, and the ability to block oxygen.
The findings could have implications for food packaging, which needs to keep oxygen out while remaining strong and flexible enough to withstand processing, transportation, and storage. By rearranging polymer chains into rings, the researchers created materials that blocked oxygen as effectively as a widely studied biodegradable plastic while being significantly tougher and better able to stretch without breaking.
The work, led by Rong Tong , professor of chemical engineering , in collaboration with Yifan Cheng , assistant professor of food science and technology , was published in Nature Communications and supported by the National Science Foundation.
Most conventional plastics consist of long, linear molecular chains. The research team, which included Ph.D. students Ziyu Huo, Xiaoyu Xie, and Huida Duan, altered plastic's molecular architecture.
The researchers joined the ends of polymer chains to form continuous rings. They also controlled the sequence of the molecules within each ring, gradually changing the composition from one type of building block to another to create what researchers call a “gradient” polymer.
The resulting polymers contained properties that are often difficult to achieve together.
“By controlling both the shape and the sequence, we are able to make materials that are strong, tough, flexible, and good at blocking oxygen,” Tong said.
One material recovered much of its shape after being stretched and fractured. Tong said the combination of strength and toughness was particularly surprising.
“Usually, when you improve the strength of a material, you have to make some sacrifices — the material could become more brittle, for example,” he said. “But here, we see both the strength and the toughness improve together. That shows us that the ring-shaped structure and the controlled arrangement work together in a way we haven't seen in previous approaches.”
Several of these cyclic polymers showed oxygen-barrier properties comparable to polylactic acid, or PLA, a widely studied biodegradable plastic.
PLA blocks oxygen well, an important property for food packaging because oxygen exposure can degrade food. But its brittleness limits broader use in packaging.
The Virginia Tech materials matched PLA's oxygen-barrier performance while demonstrating substantially greater toughness and ductility.
“For decades, developing better plastics has largely focused on changing what they're made of,” Cheng said. “Our work suggests that how the molecules are arranged, whether as lines or circles, can be just as important. That opens up an entirely new design space for creating packaging that protects food, performs well, and is easier to recycle or recover at the end of its life. Creating better food packaging is a balancing act, and these cyclic polymers give us a new way to balance strength, functionality, and sustainability at the same time.”
The materials are not yet ready for commercial food packaging. Tong and Cheng next plan to process the polymers into films and other forms to test how they withstand storage and transportation conditions — and whether their molecular building blocks can be recycled or recovered.
For Tong, the possibility of recovering and reusing those building blocks is a key goal. “The material itself is degradable,” he said. “But for more economic applications, we hope not only to degrade it, but also to recycle it and use the degraded material to make additional plastics.”
That vision may still be a long way from the grocery-store shelf, but the research points to another approach to designing plastics: changing molecular architecture to balance performance, degradability, and the potential for material recovery.
Original study : doi:10.1038/s41467-026-77071-5
Nature Communications
8-Sep-2026