Scientists have discovered that cellulose diacetate foam (CDA) is the quickest degrading bioplastic in ocean waters. This innovative foam is shown to be a practical substitute for Styrofoam items and single-use plastics, such as food containers, as it offers all the advantages of conventional plastics without adding to plastic waste. Researchers assessed this biodegradable foam in a seawater flow-through tank. After 36 weeks, the CDA foam lost 65-70% of its weight, degrading 15 times faster than solid CDA.
Researchers at the Wood Hole Oceanographic Institution (WHOI) have been investigating which plastics have the shortest and longest lifespans in marine environments for several years, aiming to identify plastic products, such as straws and food wrappers, that mainly contribute to marine pollution. As more biodegradable materials, like cellulose diacetate (CDA) — a polymer made from wood pulp — are being developed, scientists are eager to ensure they can replace conventional plastics without harming ocean ecosystems.
After years of research, a new version of CDA has emerged as the fastest degrading bioplastic in seawater — a promising alternative to foam plastic products like Styrofoam, which can remain in nature for an extensive period. In a recent publication in ACS Sustainable Chemistry & Engineering, WHOI researchers Bryan James, Collin Ward, Chris Reddy, Yanchen Sun, and Kali Pate found that introducing small pores, known as foaming, into CDA enabled it to break down 15 times faster than solid CDA and even faster than paper.
“What excites me most about this study is its translational nature. This work is the result of years of research that aims to understand how CDA biodegrades in the ocean,” stated Ward, the senior author. He, along with the WHOI team, collaborated with Eastman, a bioplastic manufacturing company, which provided funding, co-authored the research, and supplied materials for the study.
“We took foundational knowledge and applied it to create a new material that not only meets consumer demand but also degrades in the ocean more rapidly than any other plastic material currently known, even faster than paper. This is a significant achievement in an area that often emphasizes the problems caused by plastic waste, rather than exploring possible solutions,” Ward continued.
The study involved observing both foamed and solid CDA in a tank filled with constantly flowing seawater from Martha’s Vineyard Sound within a specially designed laboratory at WHOI. The team also managed variables like temperature, light exposure, and other environmental factors to closely resemble real marine conditions.
“Using constantly flowing seawater allows us to replicate the dynamics of the microbially rich ocean in the lab. Since the ocean is always changing, it’s crucial to mimic this environment by refreshing microbes and nutrients, thereby creating a much more realistic experimental setting,” lead author James explained. After 36 weeks, the researchers found that CDA foams had lost 65-70% of their initial mass.
In a prior research project using this dynamic seawater tank, the team examined straws made from regular plastic, paper, solid CDA, and foamed CDA. They discovered that solid CDA and paper straws lost mass more quickly than others. When comparing two straws made from CDA — one solid and one foamed — they noted that the foam straw degraded 190% faster than the solid straw, leading to a reduced anticipated environmental lifespan compared to paper straws.
“As a materials scientist and engineer, I’m thrilled to demonstrate that foams can use materials efficiently, achieving functionality with minimal material, thus lowering costs and environmental impacts,” said James. “Moreover, when created from biodegradable substances, foams can represent one of the least lasting forms of material.”
The urgency of replacing Styrofoam and other single-use plastics, particularly take-out containers that regularly pollute the ocean and aren’t biodegradable, is emphasized by the study’s authors. Foamed CDA products are already beginning to hit the market, with Eastman launching a compostable, lightweight tray made from foamed CDA intended to replace conventional plastic trays used in commercial food packaging.
“Collaborations between industry and academia are critical for fast-tracking solutions to pressing global issues, where academic insights can be leveraged by industry partners for large-scale solutions,” noted Jeff Carbeck, Vice President of Corporate Innovation at Eastman. “That is how our partnership with WHOI functions; it has significantly enhanced our understanding of the degradation process of our commercial and developmental materials.”
Carbeck emphasized the promise that CDA foam holds in tackling issues related to single-use plastic packaging. “The characteristics of foams make them ideally suited for numerous packaging and insulation uses, and this research indicates that foams made from biodegradable materials will decompose rapidly in the marine environment if they accidentally end up there. Adopting biodegradable products for consumer use is vital for protecting our ecosystem, minimizing plastic waste, and promoting sustainability for future generations,” he remarked.
“One of the benefits of working with an industry partner is that we can guarantee that the new technology is scalable. One of the goals in designing the new material was to make it a seamless, easy replacement for Styrofoam products, meaning companies converting raw CDA into biodegradable foam wouldn’t need to invest in new machinery,” Ward elaborated. “Creating new plastics that are not derived from fossil fuels, are compostable, and do not leave pollution in the environment can benefit both consumers and the planet.”
