Plastic pollution is nothing new; the million tons of plastic waste being dumped into the ocean yearly is a repeated cycle. Scientists have been trying to find degradable plastic that does not heavily impact the earth. While they have succeeded, the issue of microplastics remains.
Microplastics have been the biggest concern since plastic smaller than 5 mm could harm animal life and humans. In food alone, more than 7 types of microplastics are consumed daily, and 50,000 to 120,000 annually. While they have their negatives, Yorba Linda High School student Eleni Patel (10) says, “Microplastics are good for the environment because they trap contaminants in the water and serve as a filtration for pollutants.”
Conversely, microplastics are invasive, causing physical harm to marine life. However, a new study led by Japanese researcher Takzo Aida found a cure for the invasive microplastics in the ocean (Nerc.org).
In the study, the new plastic was created by combining two ionic monomers that form cross-like salt bridges, which provide strength and flexibility. In the initial tests, one monomer was sodium hexametaphosphate, a common food additive, and the other was a guanidinium ion-based monomer. The bacteria can break down both and ensure the plastic becomes biodegradable once dissolved into its components. Though the reversible nature of these bonds makes them seem weak and brittle, it is the opposite. The new structures are irreversible unless they come in contact with electrolytes like seawater. This was the key discovery of biodegradable plastic (riken.jp).
When the two monomers were mixed in water, they separated into two liquids, like oil and water. One was thick and viscous, containing structural coss-linked bridges, while the other was watery and held salt ions. For example, mixing sodium hexametaphosphate and alkyl guanidinium sulfate expels sodium sulfate into the water layer.
The final plastic, alkyl SP2, was made by drying the thick viscous layer. The new plastic is non-flammable and can be reshaped at temperatures above 120 degrees Celsius. By testing different types of guanidinium sulfates, the researchers concluded that varying hardness and tensile strength were all comparable to or better than conventional plastic.
This discovery opens the door to more possibilities. New types of plastic, such as silicone-like plastics or low-tensile flexible plastics, can be customized for needs. These plastics can also be used in 3D printing and medical or health-related items (Nerc.org).
