Durable plastic gets a sustainability makeover in novel polymerization process | Hacker News Reader

Durable plastic gets a sustainability makeover in novel polymerization process

phys.org

89 pointsPaulHoule29 comments

The "sustainability makeover" reads like it can in principle be recycled, and if we really want to we can make it from plants (though we likely wouldn't).

I don't have access to the full paper, but "Flexible and soft, the resulting material can be completely chemically recycled using heat and degraded by acid" doesn't inspire confidence that it would actually degrade well in nature. At least from that short description it does at least sound economically viable for deliberate recycling. At least with the right incentives.

They call it "bio-sourced material". Now I don't have a chemistry degree, but my amateur understanding is that most of the synthesis chains available here ultimately derive from oil. For example you can get DHF by catalyzing 1,4-butanediol on cobalt or aluminum oxide. Wikipedia lists a number of ways 1,4-Butanediol is made industrially, but they all boil down to oil product, natural gas, or the occasional "we mostly make this from oil, but sometimes ethanol is used instead". The most "bio-sourced" of those is via Butadiene, where wikipedia claims "While not competitive with steam cracking for producing large volumes of butadiene, lower capital costs make production from ethanol a viable option for smaller-capacity plants."

It reads like a nice material, but as usual temper your expectations

Nearly any petrochemical derived polymer can also be constructed from plant sugars. Much of this has been known for a while and the real question is how to scale these processes industrially and integrate them with existing supply chains for plastic production. In this case it appears that alcohol is synthesized from plants for production:

... synthesis and characterization of a strong thermoplastic made from 2,3-dihydrofuran (DHF), a monomer made in one step from 1,4-butanediol, a bioalcohol already produced on the plant scale. ...

from https://pubs.acs.org/doi/abs/10.1021/jacs.2c06103

Interesting comment, thank you.

One thing I would go miles and miles to avoid - having it break down during use, releasing god knows what into my food.

Acidity breaks it down? What if some ketchup in bun or some other acidic part of food is wrapped with it? In 2 hours when you unpack you look at holes in that plastic wondering if you will eat that material (of course you will). Had enough BPAs and PFOAs scare to not trust novel chemical crap from companies that have no issue poisoning half the planet for profit and having real food safety only as an annoying afterthought.

Indeed. I'm not a big fan of Teflon. But at least it's almost completely inert (unless overheated), which makes it much less likely to be harmful than substitutes.

> But at least it's almost completely inert (unless overheated), which makes it much less likely to be harmful than substitutes.

I don’t think that’s a strong argument. Asbestos is quite inert, and that is what makes it so harmful. A fiber will, over time, harm more and more cells.

Teflon isn’t a sub-cellular sized needle though.

Probably breaks down to shorter chain PFAS

https://chemsec.org/the-teflon-chemical-ptfe-is-often-touted...

Although it is claimed that very little migrates to food

https://www.fda.gov/food/process-contaminants-food/authorize...

The monomer used to make it is considered "probably carcinogenic"

https://en.wikipedia.org/wiki/Tetrafluoroethylene#Safety

so occupational exposure at the factory and environmental release are concerns.

> The monomer used to make it is considered "probably carcinogenic"

Yeah, this is what I heard before. That the coating itself isn't so bad, but the manufacturing process produces stuff that is awful enough that we probably shouldn't use it.

"overheated" seems to be doing a lot of work here. It's extremely easy to heat a teflon coated pan to the point where it becomes harmful. Teflon flu isn't good for humans and is absolutely fatal to birds. Non-stick cookware releases toxic gases at typical cooking temperatures. https://pubmed.ncbi.nlm.nih.gov/28913736/

yup, acidity breaking plastic down is a big no no, for ANY human contact or use in a engineered structural component. the latest "eco plastic" offering fits into the same category as the latest battery tech, wonder food, la la la, foofoo berries. Some of these things WILL pan out eventualy, but the evaluation needs to be cold blooded, and explicit based on access to real test data and real world third party evaluation. Till then it's quasi organic energy enhancing foo foo berry powder, though the expectation is that we all abase ourselves before the deployment of the magic word, sustainability.

The underlying problem of course is that recyclable and biodegradable properties are almost always at complete odds with durable, stability during use, chemically non-reactive.

This is a human issue. When in use, we expect the material to be durable. When we throw it away, we expect the material to decompose. We do not have materials that react to human intention.

But it is problematic when electrical insulations and personal ID cards start to decompose over the courses of 5-10 years.

Could be solved with a tax policy, durable plastics being made more expensive to encourage reuse and conversely biodegradable less durable plastic taxed less. Eventually things converge naturally towards an equilibrium.

nah - you can’t have something which both resists degradation when exposed to food, the environment, etc. AND naturally biodegrades in a reasonable time.

it’s like wanting a useful fuel which doesn’t burn. they mutually contradict each other.

I think the #1 concern about plastic waste are single-use plastics. For instance you might get takeout food in a polystyrene clamshell, foamed or not. Lately I noticed this product line

https://www.healthychoice.com/cafe-steamers

which are some of the tastiest frozen meals on the market, but they not only come in a plastic bowl, but there are two layers of the plastic bowl, one of which is perforated to separate the sauce from the food so that the food gets steamed. Boy is there a lot of plastic.

Thing is, these are all thermoplastics

https://en.wikipedia.org/wiki/Plastic#Classifications

unlike the thermoset plastic that this article is about. I mean, if you make a plastic bowl out of this thermoset

https://en.wikipedia.org/wiki/Melamine_resin

and use it thousands of times the amount of waste generated is dramatically less than is generated by those steamers. The environmental risk people are most concerned out now is that some fraction of plastics are not recycled, burned, or landfilled and wind up in the environment where they get ground into microplastics. As much as people blame industry on blaming the consumer, it's a lot better to chuck plastic in the trash than to chuck it outdoors and a good idea to pick it up on the side of the road whenever you can. That black agricultural plastic is a disaster. (See also the risk of plastic car tires!)

Adding some personal analysis to your point, the last time I looked at plastic market research in detail, the two biggest markets by volume and revenue were packaging and insulation, which I believe were dominated by thermoplastics. Those are the big ones if you want to make an impact on plastic usage.

Also, pulling from memory that may not be quite right, but I recall roads taking a substantial amount of polymer additives and that tire degradation is a major source of microplastic exposure for humans. The tire problem is poised to get worse with EVs being so heavy and accelerating so hard that the tires are bigger and wear faster, but I'm not aware of even any promising research there besides more bio-based feedstocks to improve the sustainability.

In building there is also a lot of use of PVC which is environmentally awful, for instance for flooring and siding.

https://en.wikipedia.org/wiki/Polyvinyl_chloride#Health_and_...

Having worked in polymers and seen the development of some recyclable, 3D-printed thermosets like what's proposed here, I think this is a fair take. On the whole, I'm glad to see other researchers continuing to research the space.

There are a few big challenges to be managed. One is material diversity—it's cool they got it to work with one monomer (most thermosets are two that you mix together), but it's a long road to showing the process works well in just one application let alone. To make a substantial impact, the process would have to be suitable to a bunch of different applications, likely requiring different material properties that would require many different monomers.

Then we can talk about value. While the value of fully recycling plastic can be managed as an externality by government taxes/fees, the big question is how much it actually costs in energy, time, money, and material waste that somebody has to pay for—there's no free lunch here, and it's rolling all those costs back up into the product. I have been secretly hoping that automated waste sorting and excess solar capacity could be used to run such waste management processes and close the business case, but energy demand and prices seem to only be going up due to AI. Still, it's good there's another example of it being possible but a long road to really reducing single-use plastics.

I don't understand why recycling plastics is desirable. Plastics are made from hydrocarbons, right? So putting them in the ground amounts to carbon sequestration, which is good? What am I missing?

1. We aren't burying them sufficiently to take them out of the biosphere, that'd be expensive.

2. Even if we could, plastics are generally not made from hydrocarbons pulled out of the biosphere, so it doesn't counter CO2 emissions and global warming.

Has there been any research into some layered degradable solutions, where the first layer can handle water but not sunlight and the second layer can handle sunlight but not water and as soon as they, by friction, separates they start degrading by the elements?

Not handling sunlight might not be ideal, but it is something instead of seeing our seas and beaches slowly turn into dumps and our bodies into plastic containers.

We've spent 100 years trying to make polymers that last forever, and we've realized that's not actually a good thing," Fors said.

Indeed not a good thing for continued profits and the cartel of planned obsolescence.

And fish

Microplastics are a major issue for all animals and maybe for all living things.

Never been a problem and likely never will.

That's a lot of confidence for a field of research that is relatively new

It's "research" that's highly politicised and much of it is junk (see the "black plastic" scare not long ago).

Synthetic fibers are around a century old by now, other plastics applications more than that, and everyone has already been exposed to microplastics. If they were as harmful as the scaremongers want us to believe, we would've noticed long ago.

Just like non-ionising radiation from radio, this whole plastics scare is another nothingburger.

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