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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)
(Score: 4, Interesting) by Immerman on Thursday May 09 2019, @05:45PM (2 children)
A big part of the problem is that in an effort to encourage people to recycle, we've tried to make it "easy" for them - and in the process destroyed the viability. You can't lump #1, 2, 3, etc. plastics together - it's all but impossible to separate them cost effectively for recycling ( To say nothing of the increasing trend of manufacturers bonding materials together into unrecyclable composites). The consumer needs to separate them before disposal, or we need to develop AI capable of doing so reliably so that we don't have to ship it to the other side of the world for people to separate for pennies a day. Or, we need a single "universal plastic" that can be readily recycled into whatever form and properties are needed.
Paper, glass, and metal are relatively easy to separate and recycle based on physical properties (density, magnetism, melting point, etc), though efficiently recycling glass kind of calls for us to get used to everything being either clear or mud-colored, or with a bit more sorting a small palette of different colors. And organic waste is a problem primarily when it's mixed in with paper or toxic substances that can't be readily separated out. Food deposits are not exactly difficult to remove from plastic, glass, or metal, especially after they've been shredded.
Of course the real wins would come from avoiding recycling as much as possible, and focus on reuse instead. There's no reason that you should buy so much stuff in single-use disposable containers in the first place - it used to be that you'd bring your own bottles of your desired size into the store and fill it from their casks. We could go back to that, though it would likely mean giving up having every-F'ing-thing available in thirty different varieties from ten different manufacturers.
If we want to take the pressure off consumers, while maintaining disposable containers, then I think you're on the right track - tax plastics severely (with a possible exception for this new PDK stuff that doesn't need sorting - after the traditional plastics have been mostly phased out. Or maybe allow just two of the most useful? Perhaps clear+flexible and rigid grey? Cover 80% of the usage with two obviously different varieties and you'd solve a lot of the problems), double-tax any sort of not-easily-separable composites. Tax the production of non-standard colors of glass. Make it so that manufacturers who make it easy to recycle their products and packaging can sell their products substantially cheaper than otherwise identical products that aren't easy to recycle.
(Score: 1, Informative) by Anonymous Coward on Thursday May 09 2019, @06:55PM (1 child)
In Germany (and many other nations), PET bottles cost $0.25 deposit. When you return them to machine, it gets chopped up and you get coupon back which gives you nice stream of Type 1 plastic chips. There is also collection of all packaging materials (except paper, glass) in separate bags, which should capture most of this garbage. But then they ship some of it to south-east Asia .....
https://www.dw.com/en/german-plastic-floods-southeast-asia/a-47204773 [dw.com]
So there is no easy solutions except demand a no-landfill, no-export-to-landfill solution. And sadly, the best we could hope to do is separation and burning of this stuff.
(Score: 4, Insightful) by Immerman on Thursday May 09 2019, @08:40PM
Still an improvement over the US, but far from ideal.
I think a key to solving the problem is included in that article "But companies that produce synthetic materials only accept recycled plastics when they're at the same level as raw oil in terms of price and quality."
Easy enough to tilt the balance - charge a massive tax on non-recycled plastics. Perhaps 300% of the cost of the equivalent amount of raw oil would be sufficient to motivate them?