For years, researchers have been searching for the fastest biodegradable plastic in the marine environment, as millions of tons of plastic are washed into the ocean every year. Now, a team of scientists from the Woods Hole Oceanographic Institution (WHOI) has discovered that CDA is the fastest-degrading plastic in seawater, technically classified as a bioplastic. However, they have accelerated the material’s degradation by using a simple modification technique called “foaming,” which makes it more porous, New Atlas reported on October 18.
CDA, or cellulose diacetate, is made from cellulose, a natural polymer found in plant cell walls, especially cotton or wood pulp. CDA has been around since the late 1800s and is used in a wide range of items, from cigarette butts (its most common use) to sunglasses frames, photographic film, and millions of other things used in everyday life.
In the new study, the team made foamed CDA degrade 15 times faster than solid form, even faster than paper. The new study appears in the journal ACS Publications.
“We’ve taken the fundamental knowledge to design a new material that meets consumer needs and degrades in the ocean faster than any other plastic we know of, even faster than paper,” said Collin Ward, lead author of the study.
In a 36-week test, when placed in tanks containing continuously flowing seawater, the CDA foam lost 65 to 70 percent of its original mass. Another common plastic found in every ocean in the world, Styrofoam, did not degrade in the same amount of time.
For the new study, Ward and other WHOI scientists collaborated with bioplastics company Eastman, which provided the materials, funded the study, and is a co-author. The research was carried out in a controlled environment in the laboratory, where the team controlled light, temperature and other factors to simulate ocean conditions.
The new research will help industries reduce their use of traditional plastics and move towards more environmentally friendly alternatives. The success of the foamed CDA suggests that the material could be used in a variety of products, helping to reduce the amount of plastic waste that is difficult to degrade in the ocean. Eastman has already produced biodegradable and compostable trays from foamed CDA to replace the conventional foam trays used for meat packaging, which do not biodegrade in any natural environment, whether on land or at sea.