New type of plastic is a recycling dream

Enlarge (credit: Elliot Margolies)
Recycling sounds great in principle (because it is), but a frustrating number of devils lurk in the details. For example, while some materials like aluminum can readily be melted down and turned right back into new aluminum cans, recovered plastics tend to be lower quality than “virgin” material. That’s because recycled plastic retains some of its previous properties—like Lego bricks that can’t be separated. The next plastic you make won’t be exactly the same type, and the recycled material won’t fit perfectly into its new spot.
To improve this situation, plastics engineers want to create new materials that can cleanly and easily break down to the most basic components—individual Lego bricks that can be reassembled into absolutely anything. The difficulty of this task is increased by all the pigments, flame retardants, and other additives used in plastics. But a group led by Lawrence Berkeley National Laboratory’s Peter Christensen has developed a new plastics process that conquers these challenges.

The basic building block of a plastic is called a “monomer”—connect monomers together and you create “polymers” with the useful physical properties you’re after. In this case, the researchers are using triketones and amines as building-block monomers. The process for putting them together sounds like minor sorcery (as chemistry often does): combining chemical ingredients causes different building blocks to form, which then spontaneously assemble.
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