With the increasing burden of rubber and plastic waste on earth, the need to reduce waste and pollution through closed-loop recycling (i.e. recycling recyclable rubber and plastic) is becoming more and more urgent. Recently, a team of researchers in the Department of chemistry at Princeton University announced the discovery of a new molecule that can help achieve closed-loop recovery.
It is reported that this is a new polybutadiene molecule. The molecule comes from a material known for more than a century and used to make common products such as tires and shoes. The research results were published in the famous scientific journal Nature communications on the 25th of this month.
Specifically, it is reported that during the polymerization process, a molecule called (1,n '- divinyl) oligocyclobutane is linked in a repeated square sequence, which is a previously unrealized microstructure that can reverse or depolymerize the polymerization process. In other words, butadiene can be "compressed" into a new polymer; The polymer can then be decompressed into an original monomer for reuse.
In the past, depolymerization was accomplished through expensive niche or special polymers, which required many steps, but common raw materials such as polybutadiene have never been used to complete depolymerization. Polybutadiene is one of the seven major petrochemical products in the world. Butadiene is a kind of abundant organic compound, which is the main by-product of fossil fuel development. It is used to make synthetic rubber and plastic products.
"Using a very common chemical that people have studied and polymerized for decades to produce a new material, let alone make it have interesting innate properties, is not only unexpected, but also a real big progress," the researchers said
"Humans are good at making butadiene. When you can find other useful applications for this molecule, it's very good because we have a lot of this molecule." The researchers added.
The chemical industry usually uses a small number of components to make most commercial plastics and rubber. Three similar examples are ethylene, propylene and butadiene. A major challenge in recycling these materials is that they often need to be combined and then added with other additives to make plastics and rubber. Additives can provide the desired performance characteristics, such as the hardness of the toothpaste cover or the lightness of the grocery bag. However, these "components" must be separated again in the recovery process.
However, the chemical steps involved in the separation process and the energy investment required to realize the separation make the recovery cost high, especially for disposable plastics. Plastic is cheap, light and easy to use, but its design does not take into account waste disposal. The researchers said that this is a major and constantly "snowballing" problem facing the world.
As a possible alternative, the above research shows that butadiene polymer is almost equal to monomer in energy, which makes it a candidate material for closed-loop chemical cycle. The researchers are excited about the prospect of this oligocyclobutane and plan to conduct more in-depth research on this sustainable and chemically recyclable material.