Scientists at the Wood Hole Oceanographic Institution (WHOI) have dedicated years of research to uncovering the lifespans of different types of plastics in the ocean and identifying the major contributors to plastic pollution, such as straws and food wrappers. With the development of biodegradable materials like cellulose diacetate (CDA) derived from wood pulp, researchers are working to ensure they can replace traditional plastics without harming ocean environments.
After extensive testing, a new version of CDA has emerged as the fastest degrading bioplastic material tested in seawater. This breakthrough offers promising potential as a replacement for foam plastic materials like Styrofoam, which can persist in the environment for many years.
In a recently published paper in ACS Sustainable Chemistry & Engineering, WHOI scientists Bryan James, Collin Ward, Chris Reddy, Yanchen Sun, and Kali Pate discovered that adding small pores, known as foaming, to CDA material accelerated its degradation rate to 15 times faster than solid CDA, even faster than paper.
“What excites me most about this study is its translational nature. This study is the culmination of years of research focusing on understanding the fundamental controls on CDA biodegradation in the ocean,” said Ward, senior author of the study.
“We translated the foundational knowledge into the design of a new material that simultaneously meets consumer needs and degrades in the ocean faster than any other plastic material we know of, even faster than paper. It’s a great success story in a field that often focuses on the negative aspects of plastic pollution rather than working towards solutions to the problem,” Ward added.
In the study, researchers monitored the degradation of both foamed and solid CDA in a continuously flowing seawater tank at a state-of-the-art lab at WHOI. The lab’s controlled environment allowed the team to mimic natural marine conditions by regulating temperature, light exposure, and other variables.
“Using continuous flowing seawater tanks enables us to bring the dynamics of the microbially active ocean into the lab. The ocean is continually changing, and it was important that we replicated this environment by replenishing microbes and nutrients, making for a much more environmentally realistic experiment,” lead author James explained.
After 36 weeks, the study revealed that CDA foams lost an astonishing 65-70% of their original mass.
In a previous experiment using a dynamic seawater tank, the scientists tested various types of straws, including standard plastic, paper, solid CDA, and foamed CDA. The results were eye-opening: solid CDA and paper straws degraded the fastest.
Further comparisons between two CDA straws, one solid, and one foam, uncovered an astounding 190% faster degradation rate for the foam straw compared to its solid counterpart. This finding suggests a significantly shorter projected environmental lifetime for foam CDA straws compared to paper straws.
“As a materials scientist and engineer, it’s been exciting to demonstrate that foams can be materially efficient, meaning they achieve functionality using the least amount of material possible, reducing cost and many environmental impacts,” said James. “In addition, when they are made from biodegradable plastics, they can be one of the least persistent forms of a material.”
The urgent need to replace environmentally harmful materials like Styrofoam and single-use plastics cannot be overstated. Take-away containers and plastic trays are contributing to ocean pollution and are not biodegradable.
The recent study has highlighted the potential of foamed CDA products to address these challenges. Eastman has already introduced a compostable, lightweight tray made of foamed CDA, offering a promising alternative to traditional plastic trays. This breakthrough is a significant step towards reducing single-use plastic packaging and tackling environmental issues.
“Partnerships between industry and academia are essential for accelerating solutions to the most urgent global challenges, where academia can provide unique insights, and industry partners can use those insights to develop solutions at scale,” said Jeff Carbeck, Vice President of Corporate Innovation of Eastman. “That is how our collaboration with WHOI works; they significantly broadened our understanding of how our commercial and developmental materials degrade.”
“The properties of foams make them ideally suited for many packaging and insulation applications, and this research shows that foams made of biodegradable materials will rapidly degrade in the marine environment, should they accidentally end up there. Embracing biodegradable materials for consumer goods is a critical step towards preserving our environment, reducing plastic pollution, and fostering sustainability for future generations,” he said.
Journal reference:
- Bryan D. James, Yanchen Sun, Kali Pate, Rahul Shankar, Mounir Izallalen, Sharmistha Mazumder, Steven T. Perri, Katelyn R. Houston, Brian Edwards, Jos de Wit, Christopher M. Reddy, Collin P. Ward. Foaming Enables Material-Efficient Bioplastic Products with Minimal Persistence. ACS Sustainable Chemistry & Engineering, 2024; DOI: 10.1021/acssuschemeng.4c05822
