MSU packaging researchers develop easier-to-recycle multilayer plastics
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EmailMSU researchers, with Pacific Northwest National Laboratory and DOE support, developed scalable polyester-based multilayer films that match commercial packaging performance and can be recycled mechanically or chemically.
Each year, the world produces roughly 100 million tons of flexible multilayer plastic packaging — materials that keep food fresh and pharmaceuticals safe from moisture and oxygen. Yet most of these plastics are nearly impossible to recycle due to their complex, chemically incompatible layers.
Researchers in Michigan State University’s School of Packaging and College of Engineering, in collaboration with the Pacific Northwest National Laboratory, have developed a scalable approach to address this challenge. Supported by a $1.7 million grant from the U.S. Department of Energy, the team designed polyester-based multilayer films that perform comparably to commercial packaging while offering potential for both mechanical and chemical recycling.
Their findings were published in the Chemical Engineering Journal as “Chemically and mechanically recyclable polyester-based multilayer plastics.”
New multilayer design
One of the plastics industry’s biggest challenges is making previously unrecyclable plastics recyclable. Led by Professor Muhammad Rabnawaz, Ph.D., the research team set out to re-engineer multilayer structures so they could enter both recycling streams without compromising performance.
The result is a new class of polyester multilayer plastics composed of 80 to 100 percent polyester. The films combine PET (polyethylene terephthalate) for strength and clarity with PBAT or PBS for sealability and EVOH (ethylene-vinyl alcohol) or PGA (polyglycolic acid) for barrier protection.
By keeping the chemistry within the same polymer family, at least 80 percent, the researchers achieved structures that remain compatible during recycling.
Performance comparable to commercial films
The team produced two main designs using standard cast film melt co-extrusion: a PGA-based trilayer (PET/PGA-PBAT/PBAT) and EVOH-based four-layer films (PET/EVOH/PET/PBS or PET/EVOH/PET/PBAT). This indicates the process can be scaled using existing industry equipment.
Laboratory tests at MSU showed oxygen permeability as low as 0.07 cubic centimeters millimeter per square meter per 24 hours and water vapor permeability as low as 0.08 grams millimeter per square meter per 24 hours, comparable to commercial multilayer films.
Rabnawaz, director of the NSF Center for Plastic, Paper and Hybrid Packaging End-of-Life Solutions (C3PS), described the work as a balance between performance and sustainability.
“These are high-performance materials that happen to be recyclable. Our goal was not to compromise function for sustainability,” he said.
Two recycling pathways
The films were designed to be recovered in two ways:
Mechanical recycling: The materials were shredded and remelted without compatibilizers. The recycled EVOH-based film (rTETS) retained strong material properties, showing an 11 percent higher tensile modulus and 105 percent greater impact strength than recycled PET (rPET). Unlike conventional multilayers, which become brittle after one cycle, the polyester versions remained flexible and strong.
Chemical recycling: Using a mild methanolysis process catalyzed at 190 degrees Celsius, the films were depolymerized into dimethyl terephthalate (DMT) and EVOH with approximately 99 percent purity. Recovery yields ranged from 63 to 71 percent, significantly higher than the less than 7 percent yield typically achieved with traditional multilayer packaging. The monomers were of sufficient purity for potential food-grade applications, a key requirement for packaging reuse.
Economic and environmental benefits
Researchers conducted preliminary techno-economic analyses and life-cycle assessments to evaluate cost and environmental impact. Early-stage results indicated that the EVOH-based structure (PET/EVOH/PET/PBS) could be produced for about 32 cents per square meter, similar to current nonrecyclable films. The PGA-based version costs approximately 66 cents per square meter and offers biodegradability advantages.
Training and broader impact
The DOE funding also supported training for graduate students and postdoctoral researchers, helping prepare the next generation of scientists and engineers in sustainable materials. Mohamed Abdelwahab, Ph.D., the project’s lead postdoctoral fellow, said the experience was transformative for his professional growth.
This project highlights how federal support can accelerate packaging research, translating polymer science into practical, scalable and recyclable solutions that benefit manufacturing and the economy while reducing energy use.
From lab to market
The new polyester platform could extend beyond flexible films. Rabnawaz noted that the materials are compatible with existing manufacturing infrastructure.
“What’s exciting is that the innovation isn’t just in chemistry. It’s in making circularity practical,” he said.
A circular future
The study demonstrates how strategic DOE investment can bridge the gap between laboratory research and real-world application. By integrating chemical compatibility and recyclability into material design from the start, the team created a potential model for future sustainable packaging.
“This study shows that designing for both performance and recyclability is possible and can help advance the transition toward more sustainable packaging,” Rabnawaz said.
He expressed gratitude to the U.S. Department of Energy for its financial support, the MSU School of Packaging for institutional support and the project team for their efforts.
