Material That Breaks Down In Seawater Could Be The Answer To Microplastic Problem

Our modern society generates around 460 million metric tons of plastic waste each year, with around 20 million ending up in the environment, particularly water bodies. Plastics take decades to decompose, with some types requiring hundreds of years. Even worse, as they do break down, they form microplastics, which end up being consumed by wildlife and ultimately people.

The presence of microplastics in water bodies has been a pervasive issue for many years. While biodegradable plastics like PLA are nothing new, they break down in water similarly to oil-based plastics. More recently, researchers have developed new types of plastic that decompose in a matter of days, if not hours. Scientists from the RIKEN Center for Emergent Matter Science and the University of Tokyo recently demonstrated a plastic that will dissolve in seawater within one to two hours, leaving no leftover residue. Researchers also claimed the new material can be efficiently recycled. Moreover, when placed on soil, it will break down into nitrogen and phosphorus, which act as natural fertilizers.

Instead of ethanol from corn, the RIKEN team used supramolecular plastics, which are held together by reversible interactions. Two ionic monomers are combined to form cross-linked salt bridges, which researchers say provide strength and flexibility. In early tests, one of the monomers was sodium hexametaphosphate, a common food additive and a component in toothpaste.