Scientists led by Takuzo Aida have created a sustainable, resistant and recyclable plastic that decomposes in the sea and does not generate microplastics, offering an ecological alternative.
Researchers at the RIKEN Center for Emerging Matter Sciences (CEMS) in Japan have developed a new plastic that is as resistant as conventional and biodegradable plastic, with the special characteristic of decomposing in seawater, it was announced this Thursday.
The experimental results of the team led by Takuzo Aida are published in the Friday edition of the scientific journal Science, RIKEN reports in a text about the work.
Scientists have been trying to develop materials that can replace traditional plastics, which are unsustainable and harmful to the environment. Although there are already some recyclable and biodegradable plastics, the latter, such as PLA (or polylactic acid), usually end up in the ocean, where they do not degrade.
The result is microplastics (pieces less than five millimeters), which spoil aquatic life and enter the food chain, potentially ending up in people’s bodies.
“With this new material we have created a new family of plastics that are strong, stable, recyclable, can fulfill multiple functions and, most importantly, do not generate microplastics”says Takuzo Aida, quoted in the RIKEN text.
The chemist’s team focused on supramolecular plastics (polymers with structures that are held together through reversible interactions), which can be degraded or recycled, to try to solve the problem of microplastics.
The new plastics They were made by combining two ionic monomers, which form “salt bridges” in the form of a network, which gives them strength and flexibility..
Monomers are small molecules made up of a single mer, while polymers are made up of several mers.
“In initial testing, one of the monomers was a common food additive, sodium hexametaphosphate, and the other was any of several monomers based on guanidinium ions,” the text states, adding that both “can be metabolized by bacteria, ensuring its biodegradability once the plastic dissolves and its components are separated.”
While the bonds in supramolecular plastics are “reversible in nature,” the salt bridge structure of the new material is irreversible unless exposed to electrolytes such as those found in seawater.
The scientists’ main discovery was “how to selectively create these irreversible cross-links.”
When the new plastic was dissolved in salt water, the scientists “were able to recover 91% of the hexametaphosphate and 82% of the guanidinium in powder form, indicating that recycling is easy and efficient” and, on land, sheets of the new “completely” plastic. It degrades in 10 days, providing the soil with fertilizer-like phosphorus and nitrogen.”
After creating “a strong and durable plastic”, which “can dissolve under certain conditions”, The researchers tested the quality of the new material and concluded that it is neither toxic nor flammable. (“which means there are no emissions of CO2”, the main greenhouse gas), in addition to being “reconfigurable at temperatures above 120 °C like other thermoplastics.”
According to RIKEN, the team was able to produce plastics that were stronger and weaker and with different tensile strengths, meaning that the new material “can be adapted as needed” and transformed into a rigid or rubber- and silicone-like plastic. Marine-degradable plastics can be used in 3D printing.
Source: Observadora
