New type of marine plastic degrades quickly under ultraviolet light
One of the grave problems with plastic waste in the ocean is not just the mess it creates today, but the mess it might leave for centuries to come. Scientists at Cornell University have been working on more environmentally friendly forms of plastic for the fishing industry, and have come up with a new material that offers comparable strength to today’s solutions but can break down much more quickly when exposed to UV light.
According to the research team, the commercial fishing industry contributes around half of the floating plastic waste in the oceans. Be it through fishing nets, lines or ropes, the plastics used for these materials are not ones that easily degrade. Fishing line in particular has a long life in the marine environment, taking up to 600 years to biodegrade, far longer than plastic bags, which take around 20 years.
The Cornell scientists have been investigating a type of plastic called isotactic polypropylene oxide, or iPPO, as a greener alternative. While its origins date back to 1949, the team has been tweaking the recipe over the last 15 years as a way of optimizing its mechanical strength, while increasing the rate at which it degrades.
Through this long period of trial and error, the team came up with a mix of ingredients, or different variations of iPPO, that could be synthesized along a singular architecture to produce the desired results. The new form of iPPO is stable during ordinary use, acting as a durable thermoplastic for fishing purposes, but degrading far more quickly in the right conditions.
“We have created a new plastic that has the mechanical properties required by commercial fishing gear," says lead researcher Bryce Lipinski. "If it eventually gets lost in the aquatic environment, this material can degrade on a realistic time scale. This material could reduce persistent plastic accumulation in the environment.”
In laboratory testing, the team found that after 30 days of continuous UV light exposure, the polymer chains making up the plastic had degraded to one quarter of their original length. The end game for the researchers, however, is to develop a polymer that degrades entirely. While the work continues toward that objective, their new iPPO is a promising step in that direction.
The research was published in the journal American Chemical Society.
Source: Cornell University