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New plant-based plastics can be chemically recycled with near-perfect efficiency

academictimes.com

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Re: New plant-based plastics can be chemically recycled with near-perfect efficiency

#91

Post by labawi »

alpaca128 wrote: post #23
swiley wrote: post #4

Earlier quoted context omitted.

PLA can be recycled with near perfect efficiency and is available today. Also it's extremely biodegradable so throwing it out isn't the end of the world.

No, it's not. Despite what store pages love to tell you at every corner, PLA does not degrade by itself. It requires exposure to 60+ degrees Celsius for at least 6 months. Good luck building recycling plants handling this in an environmentally-friendly and economical way. Don't throw out PLA, it's barely less problematic than other materials.

I've personally seen how PLA degrades in good compost in about three weeks (can go for less if you're more active). True, it is important to go through a stage of 60+℃ for a day or so, to soften up so bacteria get in, otherwise it may indeed take 6 months to get through a solid chunk, but that is quite different from 6+ months of 60+℃.

Yes, PLA can cause some issues in nature as it is acidic (lactic acid) and in quantity throws off pH balance in soil/compost, so many composters don't like to take PLA. OTOH, it is not a difficult problem to solve, and importantly, lactic acid is not inherently toxic in reasonable quantities (muscles generate it) and it shouldn't take too long for microbes to snatch it up once it is small enough.

To put that in contrast, typical plastics consist of toxic components that you do not want in your system, or even in your garden. They are mostly inert while intact, but they tend to slowly decompose and often leach even while in use.

Examples of compositions:

ABS - acrylonitrile (toxic at low doses [1]), butadiene (Group 1 carcinogen [2]), styrene (known carcinogen [3]);

PET, PETG: phtalate (Endocrine disruptors [4])

  [1] https://en.wikipedia.org/wiki/Acrylonitrile
  [2] https://en.wikipedia.org/wiki/Butadiene
  [3] https://en.wikipedia.org/wiki/Styrene
  [4] https://en.wikipedia.org/wiki/Phthalate

Re: New plant-based plastics can be chemically recycled with near-perfect efficiency

#92

Post by dEnigma »

dawnerd wrote: post #38
tachyonbeam wrote: post #35

Earlier quoted context omitted.

I think we should recycle plastic if we can, or better yet, switch to other materials that are easier to recycle. For example, glass bottles can just be sent back to the factory, washed and reused. This is already done for beer and wine AFAIK. It could be done for milk and every other kind of drinks as well. However, if we fail to recycle plastic, isn't burying plastic in a landfill, in a way, a form of carbon captur…

If by sent back you mean crushed then yeah sure bottles are reused. Oregon for example breaks the bottles when you return them to prevent fraud.

That's horrible, if true. Do you have a source for that? A quick Google search didn't get me anywhere. At least here in Austria the glass bottles are actually cleaned and re-used.

Re: New plant-based plastics can be chemically recycled with near-perfect efficiency

#93

Post by rarefied_tomato »

specialist wrote: post #27
ratsmack wrote: post #12

>plant-based What they're based from isn't the problem, it's chemicals added to the base, such as chlorine compounds, that is the problem.

Please say more. My efforts to buy least processed cotton and wood pulp products have been largely unsuccessful. I don't need my toilet paper or t-shirts to be white.

Your concerns sound more related to https://en.wikipedia.org/wiki/Optical_brightener than chlorinated plastics.

Re: New plant-based plastics can be chemically recycled with near-perfect efficiency

#94

Post by tooltower »

cortesoft wrote: post #77
jvanderbot wrote: post #26

Earlier quoted context omitted.

I believe plastic recycling is not motivated by oil use primarily. I believe it is motivated by trash accumulation in oceans and the food chain (microplastics). There are a ton of areas of the world where plastic just piles up.

How would recycling help that? Throwing your trash in a trash can and taking it to a landfill would protect the ocean and food chain just as much as recycling it would.

It would reduce the demand for landfill space?

Re: New plant-based plastics can be chemically recycled with near-perfect efficiency

#95

Post by dEnigma »

maxerickson wrote: post #81
ClumsyPilot wrote: post #61

Earlier quoted context omitted.

That's only because we were sending plastics to them to 'reprocess', and when those countries banned it, we were dumping it there illegally: https://www.theguardian.com/world/2019/may/29/malaysia-to-se...

My recycling is sorted on site at the county dump, with rejected stuff disposed of in the dump. No way are the bundles of material they sell being shipped to Asia for disposal, it doesn't make any sense at all. That article is about the countries raising their standards for the sorted material they accept, not about the typical journey that Australian waste takes. Just think about what a non existent amount of materi…

Yes, 100 tonnes is nothing at this scale. The company I work for, a small-ish waste paper recycler, deals with about 15000 tonnes a month.

Re: New plant-based plastics can be chemically recycled with near-perfect efficiency

#96

Post by astrange »

da_big_ghey wrote: post #57
mnouquet wrote: post #40

Earlier quoted context omitted.

> [...] build millions of houses ... slowly leaching endocrine disruptors in the environment for generations to come.

This would also cut reproduction rates, which is not pleasant but is necessary to stop climate change.

It is not necessary. Malthus was wrong. You'll notice this position was popular among boomer environmentalists, which is why it was parodied just recently by 70s comic villain Thanos.

The birth rate everywhere outside Africa has already collapsed, anyway. It's probably too low.

Re: New plant-based plastics can be chemically recycled with near-perfect efficiency

#97

Post by astrange »

ramraj07 wrote: post #75
rmason wrote: post #71

Earlier quoted context omitted.

I remember a time when everything was paper bags. Groceries and retailers went with plastic because it was cheaper. But with plastic there was a hidden cost. Now we're told we must pay a premium for recyclable plastic. Personally I'd rather pay a premium for paper because it's made from a renewable resource. Plus paper will decompose within two months in nature. The only drawback I can find is that paper bags take mo…

Also not everything can be paper. A coffee cup can never be fully paper, it needs a plastic lining and can thus never be recyclable. Not without it being extremely crappy. No food item can be enclosed in a fully paper enclosure and expected to have a shelf life. And for all the Portlanders saving a plastic bag there's a Texan buying all their drinking water as pallets of disposable single use plastic bottles. I think…

I'm not sure Japan is good at plastic use. Practically everything is wrapped in 3 different layers for style points.

Japan's electricity is also so coal-based that using Japanese factories is starting to violate US companies' clean energy rules.

https://www.ft.com/content/bbd59494-ac64-4dda-8da5-a2990d893...

Re: New plant-based plastics can be chemically recycled with near-perfect efficiency

#98

Post by pkulak »

cortesoft wrote: post #77
jvanderbot wrote: post #26

Earlier quoted context omitted.

I believe plastic recycling is not motivated by oil use primarily. I believe it is motivated by trash accumulation in oceans and the food chain (microplastics). There are a ton of areas of the world where plastic just piles up.

How would recycling help that? Throwing your trash in a trash can and taking it to a landfill would protect the ocean and food chain just as much as recycling it would.

Yeah, the great irony here is that recycling is what sends the trash to Asia were it's then tossed in the ocean.

Or at least, it used to. I think most plastic "recycling" is now going into local landfills.

Re: New plant-based plastics can be chemically recycled with near-perfect efficiency

#100

Post by mnouquet »

JulianMorrison wrote: post #86
da_big_ghey wrote: post #84

Earlier quoted context omitted.

That is a good point, maybe something like one-child policy better serve this need. Or possibly we must consider which is worse for animals, damage from climate change or damage from endocrine disruptor.

The answer is neither. Human energy use that causes climate harms can be replaced with renewables. Fuel can be replaced with batteries. In the longer term, the sun is absolutely pouring out energy, which largely goes to waste, and a Dyson swarm capturing a small fraction of that would satisfy the energy needs of a much larger population.

> Human energy use that causes climate harms can be replaced with renewables

No, it can't.

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