This New Bioplastic Could Change Manufacturing: All About Sway

Seaweed is responsible for producing more than half of Earth’s oxygen and has the potential to suck up and store massive amounts of carbon dioxide. It’s a trending superfood rich in protein, calcium, folic acid, and iron, and can reduce your blood pressure and improve your digestion. It’s used in a diverse range of industries, found in everything from livestock feed and fertilizer to cosmetics, pharmaceuticals, and even ice cream.

And now, the marine plant is squaring up against single-use plastics.

Seaweed Bioplastics

Several companies are experimenting with bioplastics made of seaweed. One such company is Sway, a California-based startup founded in 2020 that is already making waves. 

Bioplastics are materials made using renewable resources as varied as sugarcane, vegetable oils, sawdust, yeast, and gluten. They are becoming increasingly popular as manufacturers seek more sustainable alternatives to traditional petroleum-based plastic, particularly for packaging. Only 9% of the roughly 507 million tons of plastic produced in the world each year is recycled. The packaging sector generates more single-use plastic than any other industry. 

Julia Marsh, Sway’s CEO and co-founder, became horrified at the plastic pollution she witnessed growing up on California’s coastline, and disillusioned with widespread wasteful packaging after initially pursuing a career in design and branding in New York. She and co-founder Matt Mayes hit upon the packaging potential of seaweed after his master’s degree in sustainable development brought him to Indonesia, where the pair explored the country’s seaweed farms.

In 2023, Sway won the Tom Ford Plastic Innovation Prize: a competition backed by the fashion designer to create biodegradable alternatives to thin-film plastic polybags. The competition assesses various metrics of new bioplastic technologies, including scalability, cost, performance, biological degradation, and environmental and social impact.

All three 2023 prize winners are experimenting with seaweed. Besides Sway, India-based Zerocircle is using seaweed to make packaging materials that dissolve after use, and London’s Notpla uses it in a coating applied to the inside of take-out boxes.

Sway’s melt-processable resin, which can be composted at home, is currently used to make luxury polybags and rolls of flexible film. In the fashion industry, some seaweed-based products contain bits of less refined green kelp for a mottled aesthetic, which is popular among jewelry retailers.

Problems With Bioplastics

Seaweed solves some of the problems associated with other bioplastics. Scientists have been experimenting with various bioplastics since the 1970s when a petroleum crisis led to a decreased supply and increased cost of oil. But composting these materials has remained  challenging. For example, most bioplastics can only be broken down in industrial composting facilities, and most US towns don’t have them. Some bioplastics don’t break down at all because they contain additives to improve their performance. Further, plant-based bioplastics, such as those made from corn, rice starch, or potato, require land use and water, and their carbon output can do more harm than good for the environment.

Sway’s seaweed product, however, can be thrown on a home composting pile and will be an organic part of the soil within six months. Described by CEO Marsh as “a magical resource”, seaweed is a regenerative, low-input ocean crop; it doesn’t need arable land, fresh water, or fertilizer, and is extremely fast growing (some species can grow two feet in a day). Seaweed provides habitats for marine ecosystems, and its gelling properties are well suited to making thin, flexible film.

That said, the product is not without its challenges. Conventional plastic sheets are generally made by heating plastic pellets or powder. Oil-based plastics melt easily, and can then be poured into a mold or blown out to make the sheets thinner. Seaweed-based plastics tend to burn rather than melt. Sway has had to experiment with adding other organic compounds to create something that melts more easily. The team has also been working on making its bioplastic more stretchy — though Marsh told Wired magazine that for a bioplastic revolution to take off, people’s expectations of how plastic should behave will need to change.

While seaweed appears to solve issues surrounding composting and land use, it is perhaps too early to know for certain that the product biodegrades reliably and that mass seaweed farming will not have unintended effects on the planet or coastal communities.

Sway’s Impact on Manufacturing

Sway will use its $600,000 winnings from the Tom Ford Plastic Innovation Prize to scale up its product portfolio, which currently includes polybags, food wrappers, and retail bags. The company also plans to continue forging partnerships with brands in fashion, food, and home goods, including J. Crew and Burton, as well as others associated with the Tom Ford prize that are keen to make the shift to next-generation packaging materials.

“Clean oceans, abundant biodiversity, and thriving coastal economies all intertwine with Sway’s success as we accelerate production in 2024,” Marsh said. “We believe everyday materials should help to replenish the planet from sea to soil. The launch of our thermoplastic seaweed materials, along with an influx of new capital targeted at scaling production, signifies tangible progress toward a more circular future.”