An innovation could finally solve the problem of microplastics. Japanese researchers have developed a new type of plastic that is as durable as its predecessors but able to decompose rapidly in seawater and soil without creating microplastics.
This promising material could mark a turning point in the fight against plastic pollution.
The development of this plastic relies on an original molecular structure: reversible salt bridges that maintain its strength. When exposed to salt water, these bonds dissolve, making the material biodegradable. Unlike current plastics, such as PLA, which often resist degradation in marine environments, this new compound does not produce microplastics.
The work of the team at the RIKEN Center for Emergent Matter Science, led by Takuzo Aida, utilized supramolecular polymers. These polymers are characterized by reversible bonds, a property usually considered a drawback. However, the researchers have demonstrated that these materials can be both strong and stable.
To create this plastic, two ionic monomers were combined: a common food additive, sodium hexametaphosphate, and an ion-based guanidinium monomer. A key step in the process, desalination, allowed for the formation of a rigid structure. Placing the plastic back into salt water reverses the process, breaking it down into its constituent elements.
During testing, the material exhibited properties comparable to or even better than conventional plastics. By varying the components, the researchers successfully adjusted its characteristics: scratch resistance, flexibility, or the ability to bear loads. This opens up a wide range of applications, such as 3D printing or the design of medical devices.
Salt bridges play a key role in the stability and biodegradability of this innovative plastic.
Credit: RIKEN
Another major advantage lies in its recyclability. After dissolving in salt water, 91% of the initial phosphorus and 82% of the nitrogen were recovered. Furthermore, this plastic fully biodegraded in soil within ten days, enriching it with nutrients.
This material is not just biodegradable. It is also non-toxic, non-flammable, and can be processed like any standard thermoplastic. The research suggests that this plastic could also be a sustainable alternative to polymers used in food packaging or textiles.
With this discovery, Aida's team hopes to revolutionize the plastics industry by addressing critical ecological challenges. More than just a replacement, this new plastic offers a solution to the microplastics problem while allowing for broad industrial adaptation.