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posted by martyb on Thursday May 09 2019, @07:13AM   Printer-friendly
from the "The-Graduate" dept.

Endlessly recyclable plastic (Javascript required.)

By separating plastic monomers from chemical additives, researchers may have created fully recyclable plastics.

Molecular scientists at the Lawrence Berkeley National Laboratory developed a new type of plastic: polydiketoenamine, or PDK. When immersed in an acidic solution, PDK monomers were broken down and were freed from the additive compounds used in plastic production.

Berkeley Lab staff scientist Brett Helms said: "With PDKs, the immutable bonds of conventional plastics are replaced with reversible bonds that allow the plastic to be recycled more effectively."

Commercial plastics generally contain additives such as dyes or fillers to make them hard, stretchy, coloured or clear. The problem is these additives have different chemical compositions and are hard to separate from the monomers.

Also at Berkeley Lab.

See also: Researchers develop plastic that they are calling the 'Holy Grail' of recycling
This infinitely-recyclable plastic might help us finally clean up landfills and oceans

Closed-loop recycling of plastics enabled by dynamic covalent diketoenamine bonds (DOI: 10.1038/s41557-019-0249-2) (DX)


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  • (Score: 3, Insightful) by FatPhil on Thursday May 09 2019, @01:23PM (2 children)

    by FatPhil (863) <pc-soylentNO@SPAMasdf.fi> on Thursday May 09 2019, @01:23PM (#841312) Homepage
    What's wrong with cellulose? I recycle pounds of that a week. OK it takes a plant a long time to rebuild it, but it is a cycle that's been going on for hundreds of millions of years.
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  • (Score: 2) by HiThere on Thursday May 09 2019, @04:49PM

    by HiThere (866) Subscriber Badge on Thursday May 09 2019, @04:49PM (#841398) Journal

    That's not a bad point, but the wooden comb that I bought feels far inferior to the previous plastic one. I just hope it lasts 5 times as long.

    There are lots of thing cellulose is good for, and we should be using that more. But it sure isn't good for everything. And as for this latest offering....it wouldn't make good vinegar bottles.

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  • (Score: 4, Informative) by Immerman on Thursday May 09 2019, @04:59PM

    by Immerman (3985) on Thursday May 09 2019, @04:59PM (#841404)

    >What's wrong with cellulose?
    Water-solubility. Also flexibility, transparency, tensile strength, production complexity, environmental impact...

    Granted using grasses, hemp, etc as your feedstock instead of wood drastically reduces the environmental impact, but the others are more difficult to address. There's a reason plastics are so popular. Micro-, and especially nano-cellulose has some really impressive properties (think "transparent aluminum" for nano-), but they require a lot more processing to produce than simple pulp. And neither is that great for making beverage containers as they're still water-soluble.

    Recycling can be done with moderate degrees of efficiency (not composting and regrowing, but more direct product-to-product recycling), but the cost of recycling tends to rival if not exceed the cost of fresh material, and it can mostly only be down-cycled, which makes a strong business case against it.

    Overall, lots of promise for some things, but that water solubility is a major stumbling block for most that can mostly only be worked around by covering it in a protective layer that makes recycling non-viable.