The lining in traditional disposable coffee cups can release plastic particles and be difficult to recycle, but a new plant-based coating can eliminate these issues with your morning brew.
A team of researchers from the University of Waterloo created a durable new coating from cellulose acetate that is reinforced with cellulose nanocrystals. Both components come from plants. Because the coating and the cup are both cellulose-based, the material has the potential to simplify paper recycling by reducing the need to separate conventional plastic liners from paper.
The plastic in use now is derived from fossil fuels, and it can persist in the environment for centuries after disposal. During testing, the conventional, plastic-lined coffee cups showed surface degradation and particle release, suggesting microplastics could enter the container's contents and flow into our bodies. The researchers' cellulose-based coating remained largely intact during the same testing.
"Learning how easily some plastic liners can shed particles was eye-opening," said Dr. Shirley Tang, professor in Waterloo's Department of Chemistry. "The fact that we have created such a high-performance all-cellulose coating that doesn't rely on conventional plastics is what makes this work particularly exciting because there are so many possibilities."
Researchers found that the plant-based coating remained stable after prolonged exposure to boiling water, food oil, and a variety of solvents. The material also maintained its protective properties when applied to lightweight paper, such as brown paper towels.
"The coating allowed us to use much thinner paper while still achieving the durability needed for beverage containers," said Dr. Sayan Ganguly, a research associate in the Tang Nanotechnology Lab at Waterloo. "That could reduce the amount of material required to manufacture cups while maintaining performance and lowering costs. These savings could ultimately be passed on to the consumer."
The project originated from earlier research into lightweight, sustainable materials for aviation applications. While investigating renewable alternatives for aerospace uses, the team discovered the material's potential as a protective coating for paper products and packaging.
Beyond coffee cups, the researchers see opportunities for the material in food packaging and other applications where companies wish to replace plastics with renewable alternatives.
The study, A High-Temperature-Resilient All-Cellulose Barrier for Next-Generation Beverage Packaging , was published in ACS Sustainable Chemistry & Engineering.
