Plastics can be recycled many times

There is a great future for the plastic industry. Researchers report in a recent Science Report: A new plastic, when exposed to appropriate chemicals, is capable of dividing into basic blocks just like when it was created and can be re- structure again and again.

Plastic design that can be easily reused is one of the attacks against the global plastic waste problem. Only about 10% of plastics are produced for recycling, according to a 2017 study by Science Advances. But this material is so cheap and useful that hundreds of millions of tons are still being released every year.

The main obstacle to plastic recycling is that most plastics that break down into molecules are not immediately useful. Turning these molecules into plastic or some other product requires a lot of chemical reactions, making the recycling process less efficient.

And while biodegradable plastics have become popular in recent years, they only decompose if there is the right kind of bacteria. And as usual, these plastics are thrown in landfills, areas buried or floating in the ocean. Creating plastics capable of being divided into basic blocks and reused without additional treatment and cleaning can help reduce contamination.

This recyclable material is more durable than previous products to create reusable plastics.

Michael Shaver, a polymer chemist at Edinburgh University, who did not participate as a member of the study said: But designing a plastic polymer like this is a balanced action. A polymer is a long chain of small molecules, called monomers , that bind together like particles on a chain.

Monome needs extreme temperatures or too many chemicals to join into the polymer, and this is really not easy to accomplish in practice. As a result, polymers need to be stable to a temperature high enough that when pouring hot coffee into a cup made from them will not destabilize the line and make the plastic melt into a sticky pool.

Polymer chemist Jianbo Zhu and his colleagues at Colorado State University in Fort Collins discussed the challenge. The team has had some luck in the past in creating a kind of polymer that can be broken down into its starting molecules. But plastics created in their labs and other plastics all face the same problem as being too soft and sensitive to temperature, so it is difficult to use in practice.

This time, Zhu and colleagues changed one of the previous ways, a small circular molecule, by adding another molecule like that in a way that helps combine the molecule into a special structure. That hardness has enabled monomers to quickly join together at room temperature into thermally stable polymer chains.

Then, when exposed to some mild chemicals or high enough temperatures, the polymers break down into monomers. The researchers were able to repeat this cycle several times, suggesting, theoretically, the polymer could be recycled infinitely.

Chemist Zhu said: "While each monomer is locked into a specific structure, not all of them have the same shape even though they are made from the same chemical formula. Mix the other two. each of the monomers creates a stronger plastic ".

'This is probably the best system out there,' Shaver said.

However, it is still not perfect: Zhu and his colleagues are planning to join more monomers in the future, making the plastic less brittle. Finally, they hope to be able to commercialize this product.