Our land and seas are being polluted by vast amounts of plastic trash. Now, they employing chemical trickery to create materials that are indefinitely and easily recyclable.
Making bonds between atoms is something that chemists excel at. They are now dealing with the fallout from that success: plastic debris that is burnt, landfilled, or floats in the oceans. Polymers are lengthy chains of molecules joined by strong chemical bonds that make up plastics. As a result, they might be difficult to decompose or recycle. Snipping those chemical connections apart to get back to the little molecular building blocks is a difficult chemical challenge to solve.
The primary polymers we employ have met with various degrees of success. Polyethylene terephthalate (PET), which is used to produce plastic bottles, is the low-hanging fruit. It’s as simple as shredding it and remoulding it into new bottles. No chemists are required to apply.
Most other key plastics are a different story.
So one of chemists’ jobs is to come up with novel processes for breaking down plastics into molecules that can be reused. Susannah Scott of the University of California, Santa Barbara, has lately found success with polyolefins, which include polyethylene. She devised a method for breaking down these polymers into tiny molecules using a catalyst rather than a lot of heat. Detergents, paints, and medications might all benefit from these tiny molecules.
They also need to develop new polymers from the ground up, considering what will happen to them when they reach the end of their useful lives. Chemists are beginning to develop polymers that may be recycled indefinitely or decompose into soil-nourishing elements.
Ting Xu of the University of California, Berkeley, developed one such plastic. Xu stuffed the plastic with microscopic enzyme capsules. It is possible to treat, heat, and stretch the material into usable items. When its useful life is up, all you have to do is soak it in lukewarm water for a week or so. This activates enzymes that break down the plastic into smaller molecules. If we actually want to reduce the problem of plastic trash, we’ll need a lot of new materials like this.