As you read this, you are almost certainly surrounded by a world of plastic. Since the rise of petroleum-based polymers in the mid-1950s, materials have become ubiquitous in modern life — from the smart phone in your hand to the shoes on your feet. But as they have accumulated in our lives, they have infiltrated nearly every natural environment on Earth, entangling turtles, suffocating birds and littering our highest peaks. Perhaps the most visual reminder of humanity’s plastic problem comes when our waste swirls into giant garbage eddies in the middle of the Pacific Ocean. Worse, the terrifying ecological spectacle hides the fact that 70 percent of the plastic in the sea sinks to the bottom as tiny particles — fundamentally changing the composition of ocean floors and beaches around the world. If that wasn’t bad enough, by 2060, humanity’s consumption of plastics is projected to triple, while the volume leaking into the environment is projected to double to 44 million tons per year, according to the OECD’s Global Plastics Outlook 2022. But what if things could be different? What if we had something that looked like plastic, behaved like plastic but was completely biodegradable? It’s a question that has preoccupied University of British Columbia researcher Feng Jiang for the past few years. “It’s really a worrying crisis,” Jiang said in a recent interview with Glacier Media. “Less than 10 percent of single-use plastics are recycled.” An assistant professor at UBC’s School of Forestry, Jiang has looked to the trees for answers.
How solving plastics could reduce wildfires
British Columbia’s forests are choking on wood fuels, the product of years of forestry practices and a wildfire regime that heavily favored total suppression over controlled burns. As climate change leads to drier summers, fire experts have warned of a coming “wildfire crisis” unless something is done to commercialize the millions of tonnes of wood waste waiting to ignite in BC’s forests. “After harvesting, only about 50% of the materials are used,” Jiang said. “Those branches and treetops will just stay in the forest. In time, they will dry out and become fuel.” “We’re trying to take that material and turn it into packaging, and at the same time we’re trying to reduce the risk of forest fire.” With funding from the BC Ministry of Forestry, Jiang and his graduate students devised a way to distill cellulose from wood waste, although the researcher says hemp fiber and agricultural waste are also viable sources. The process breaks down the wood fibers in a cold sodium hydroxide solution. After its mechanical mixing—Jiang’s method is the first to use small amounts of energy and chemicals—the sodium hydroxide is recycled for the next batch. They then took this 100 percent cellulose solution—a similar precursor to paper—and made a transparent, biodegradable film. The original material has similar properties to the plastic used in bubble wrap or envelopes in the mail. Like its plastic counterpart, it could also be molded into bags for coffee, cereal, crisps, as well as frozen and fresh fruit or vegetables. “We can print on it too. It will work for snack packaging,” Jiang said.
Strong when wet, just toss it in the compost
To test its durability, the researchers soaked the film in water for more than a month. When it came out, Jiang said “it was still mechanically strong.” Jiang said they are still trying to add “extensibility” to the film so it can carry more weight like a disposable shopping bag. They are also working to understand how gases emitted from aging fresh vegetables can degrade the film. Most importantly, he said, the replacement plastic film remains strong when needed and can still be tossed in the compost. In one test, Jiang placed the film on soil for three weeks. At the end of the experiment, only a few small fragments remained. “Microbes in the soil will degrade it—just like vegetables degrade, they can degrade this film,” he said. Jiang says he will talk to plastic and paper makers in the coming days to find a partner that can ramp up production. “The next goal is to make a roll of plastic. The bigger the better,” he said. This way they can conduct larger scale experiments. If all goes well, he says he could have a bag ready in a few months. Jiang is well aware that the longer it takes to find a replacement for plastic, the more petroleum products will end up polluting environments around the world. Time, he said, is not something he wants to waste. “The ultimate goal is to try to fight climate change,” Jiang said, “reducing oil use and slowing fires at the same time.”
