(dr) RIKEN
Scientists from RIKEN Center for Emergent Matter Science (CEMS) have developed a new durable plastic that does not pollute the ocean.
Over time, the scientific community has tried to develop safe and sustainable materials capable of replacing traditional plastics, which harm the environment.
The biggest problem of biodegradable plastics current ones, like PLA, is that they reach the ocean and cannot be degraded because they are insoluble in water. The result is the well-known microplastics, which have harmed aquatic life and are increasingly common in the food chain.
In this new study, scientists solved this problem with supramolecular plastics — polymers with structures that are held together through reversible interactions.
According to , these new plastics emerged from the combination of two ionic monomers which form reticulated salt bridges and which provide high strength and flexibility.
In early tests, one of the monomers was a common food additive called sodium hexametaphosphate and the other was one of several monomers based on guanidinium ions. Both can be metabolized by bacteria, which guarantees complete biodegradability once the plastic is dissolved.
In this new material, the salt bridge structure is irreversible unless it is exposed to electrolytes such as those found in seawater.
In addition to being non-toxic, the new plastic it is not flammableand can be remodeled at temperatures above 120°C.
Finally, scientists investigated the recyclability and biodegradability of the new plastic and, after dissolving it in salt water, were able to recover 91% of the hexametaphosphate and 82% of the guanidinium in powder form, which indicates that recycling is easy and efficient.
In the soil, sheets of this new plastic completely degraded over 10 days, providing the soil with phosphorus and nitrogen in amounts similar to fertilizer.
The was recently published in Science.
