Scientists in Japan develop plastic that dissolves in seawater within hours

This seems like it could be a viable replacement for many plastics, but it isn't the silver bullet I feel that the article is acting as if it is.

From the linked article in the post:

the new material is as strong as petroleum-based plastics but breaks down into its original components when exposed to salt.

Those components can then be further processed by naturally occurring bacteria, thereby avoiding generating microplastics

The plastic is non-toxic, non-flammable, and does not emit carbon dioxide, he added.

This is great. Good stuff. Wonderful.

From another article (this shows that this isn't as recent, too. This news was from many months ago)

the team was able to generate plastics that had varying hardnesses and tensile strengths, all comparable or better than conventional plastics.

Plastics like these can be used in 3D printing as well as medical or health-related applications.

Wide applications and uses, much better than a lot of other proposed solutions. Still good so far.

After dissolving the initial new plastic in salt water, they were able to recover 91% of the hexametaphosphate and 82% of the guanidinium as powders, indicating that recycling is easy and efficient.

Easy to recycle and reclaim material from. Great! Not perfect, but still pretty damn good.

In soil, sheets of the new plastic degraded completely over the course of 10 days, supplying the soil with phosphorous and nitrogen similar to a fertilizer.

You could compost these in your backyard. Who needs the local recycling pickup for plastics when you can just chuck it in a bin in the back? Still looking good.

using polysaccharides that form cross-linked salt bridges with guanidinium monomers.

Polysaccharides are literally carbohydrates found in food.

This is really good. Commonly found compound, easy to actually re-integrate back into the environment. But now the problems start. They don't specify much about the guanidinium monomers in their research in terms of which specific ones are used, so it's hard to say the exact implications, but...

...they appear to often be toxic, sometimes especially to marine life, soil quality, and plant growth, and have been used in medicine with mixed results as to their effectiveness and safety.

I'm a bit disappointed they didn't talk about this more in the articles, to be honest. It seems this would definitely be better than traditional plastic in terms of its ecological effects, but still much worse than not dumping it in the ocean at all. In my opinion, in practice it looks like this would simply make the recycling process much more efficient (as mentioned before, a 91% and 82% recovery rate for plastics is much better than the current average of less than 10%) while reducing the overall harm from plastic being dumped in the ocean, even if it's still not good enough to eliminate the harm altogether.

What does it dissolve into? 🪿 Wait, what does it dissolve into? 🗣️ 🪿

From the article:

Aida said the new material is as strong as petroleum-based plastics but breaks down into its original components when exposed to salt. Those components can then be further processed by naturally occurring bacteria, thereby avoiding generating microplastics that can harm aquatic life and enter the food chain.

As salt is also present in soil, a piece about five centimetres (two inches) in size disintegrates on land after over 200 hours, he added.

The material can be used like regular plastic when coated, and the team are focusing their current research on the best coating methods, Aida said. The plastic is non-toxic, non-flammable, and does not emit carbon dioxide, he added.

So I think the next thing the goose wants to know is, what's it being coated with?
- Is it made of snails?
  
  (/s, in case anyone wants to take that seriously)
That was my first thought, a tide pod also rapidly dissolves in sea water, we shouldn't be dumping those in the ocean though.
- But then how will we maintain the ocean breeze scent?
It dissolves into salt water.

Except it doesn't dissolve, this is not the term they should be using, you can't just dry out the water and get the plastic back. It breaks down into other things. I'm pretty sure an ocean full of dissolved plastic would be a way worse ecological disaster than the current microplastic problem...

I've seen like 3-4 articles about this now and they all use the term dissolve and it's pissing me off.

Does it actually break down? Or does it just melt into a cloud of microplastics?

The perfect material for Tesla’s new cyberboat

I have a name for that boat: Cybersunk
- Thats very fitting, I would also accept CyberD (cyber dissolved)
Perfect since he's being invited to Russia now. They can share their know-how of sinking ships.

~~I feel like soluble plastic can't be a good thing actually~~

Edit: the plastic chemically decomposes in water, it does not dissolve

Looks like it's not an issue fortunately.

Aida said the new material is as strong as petroleum-based plastics but breaks down into its original components when exposed to salt. Those components can then be further processed by naturally occurring bacteria, thereby avoiding generating microplastics that can harm aquatic life and enter the food chain.
- Yeah I reacted to the title and then read the article and edited lol
- So using this for frozen foods, or takeaway containers isn’t advised. Those are basically all sodium.

It dissolves...but into what? Sounds like a recipe for a petroleum salt water mix that's probably just as toxic as melted plastic, unless all the petroleum is removed.

Instant micro plastics: just add seawater!
It doesn’t seem to be based on petroleum, since they’re explicitly comparing it to petroleum-based plastics…

There also are other non-petroleum based plastics that dissolve in water. This part is not new. E.g. polyvinyl alcohol is used widely.

What’s new about this one is that it specifically needs salt to dissolve and they claim it’s otherwise relatively sturdy. So maybe it could be used instead of pet bottles for drinks? Or maybe they’re not quite there yet but it’s a new step in that direction…
- For anyone wondering about where, just as an example, polyvinyl is: Polyvinyl acetate (i.e. PVA) is the stuff that wood glue is typically made out of. It's also the binder used for those bird seed bells.
  
  ...It does indeed dissolve in the water. In the rain, certainly, which any owner of a bird seed bell could tell you.
- There's a lot of sodium in most fizzy drinks, wonder if that rules them out for this. Or does it have to be sodium chloride specifically?
It's a bit of a stretch calling it a plastic, as it's not petroleum based from what I've read.
- Is that necessary for plastic? The name comes from the Greek for "to mould". For me, anything that makes long chain mouldable polymers is a plastic. Milk makes Casein or Galalith plastic, PLA is commonly made of corn. There's a ton of bamboo fabrics that are essentially nylon made from cellulose.

And are we gonna start using this on a mainstream scale?

We use plenty of biodegradable plastics. They’re not always the correct solution. You wouldn’t want an airplane biodegrading, for example.
- I’d love that actually. While I’m flying preferably
- they might not be even biodegradable, not unless they separated which is impossible to do

Let’s build a ship out of it.

"Oil tanker spills 60,000 tons of crude into the Pacific after hull biodegrades, more at 6"
And then tow it outside the environment.

I think some of y'all are missing a lot of packaging use cases other than food. But even in the food sector, there are dry things like pasta, beans, and rice that don't have salt in them. If it really is as strong as a petroleum plastic for these items, it could eliminate tons of micro plastic.

I've seen rice sold just in the cardboard box already.
- Yes, and flour comes in a paper bag. It doesn't stop manufacturers from trying to protect their product from incidental moisture contact.
  
  A company who already packs their product in plastic is going to have a much easier time switching to something like this than changing their whole packing line out for box packing machines.

Aida said the new material is as strong as petroleum-based plastics but breaks down into its original components when exposed to salt.

If this means that it does not break down when exposed to just water, that's a pretty big deal. Water solubility has been the major issue making biodegradable plastics useless for food packaging (typically you want to either keep the food wet and water in, or dry and water out - either way water permeability is a problem).

Of course most foods also contain salt, so... I guess that's why the article talks about coatings. If the material has to be coated to keep it from breaking down too fast, what is the point? either the coating will prevent it from breaking down, or it just moves the problem to the coating not breaking down.

Food is not the only thing that gets packaged. The worst example that comes to my mind is the way they package microSD cards.
- What, you don't think 1cm² of product should be packaged in a 7×10 cm doubled-up plastic sheet?
- Food is a reasonable target for biodegradable packaging because you don't really expect the food to sit around for more than a year (for long-term food packaging you just wouldn't use a biodegradable material).
  
  Packaging products that might have a long shelf life is more problematic. If the material breaks down in saltwater then it will start breaking down if someone picks it up with sweaty or recently washed hands.
It's cool we'll just slap some PFAS on there and fix 'er right up
Plastic coated cardboard containers exist already, and are being widely used for food.
- Well right, and coating them with plastic means that they leave plastic residue behind if they break down in an uncontrolled environment, and increases the cost and complexity of recycling:
  
  If the paper has a plastic or aluminum coating, it can be recycled, but it is much more expensive and complicated.
  
  Some plastic coatings can be separated from paper during the recycling process. Still, it is often cheaper and easier to use virgin materials to create new products than recycling paper coated with plastic.
  
  Paper coated with plastic isn’t suitable for composting, and most times, such products are incinerated for heat or landfilled rather than recycled.
  
  https://www.almostzerowaste.com/non-recyclable-paper/
  
  Yes they already exist. They are not really better than pure plastic, they're kind of a form of greenwashing because they appear to be environmentally friendly.
If the material has to be coated to keep it from breaking down too fast, what is the point?

Presumably you could only coat certain faces of the material (like ones touching food). Or maybe the coating could degrade in another more time-known fashion. So if the coating would be expected to last no more then 3 years then after the plastic could start to degrade.

You see the thing is, the point of plastic is that it doesn’t dissolve easily. I can see this having some niche applications, but this won’t be replacing most plastics any time soon.

To be fair, this was originally the point of plastic. The primary point of plastic today is that it is an extremely cheap material that you can mould into pretty much any shape.

Need a bag to carry stuff? Plastic.

Packaging for toothpicks? Plastic.

Spacers inside an electric circuit? Plastic.

Packaging for clothes? Plastic.

Fake plant? Plastic.

Part of the problem is that we're using a wonder-material that lasts forever (plastic) for a bunch of mundane shit where we don't need it, because that wonder-material turns out to be the cheapest material around as well.
- Yeah, fair enough. That’s a great point. I will update my opinion of this advancement.
Its specifically sensitive to salt, so you can use it for anything with little or no salt without issue. Also it would be perfect for basically all packaging applications that dont involve food but do require an airtight seal. So you could probably replace the majority of all single use plastic packaging/containers with it.
Ah but imagine the eager faces of Logitech's execs when they realize they could make their mice dissolve under your fingers and offer a subscription for replacements.
Well let’s stop putting plastic into seawater and we won’t have to worry about it dissolving.

I hope they can tune it to react only to a very specific type of salt water range or else it will not be applicable very often.

And I love this. More if this please

Or we can, you know, have waxed paper?

Also, I thought we've already mainstreamed starch-based plastics.

Last but not least, we've had cellophane pretty much since the industrial revoltion. The current issue has been the productionlike containing toxic materials, but the end product itself is biodegradable. Perhaps we can improve on that.

So then what can it be used for, other than being decomposed? Doesn't almost all food contain salt, and human sweat as well? It's not really useful on earth then, is it? Maybe for unmanned spacecrafts?

Well, the dream material would be some that is stable during use and then immediately falls apart when disposed. But that's not how things usually work, so anything that decomposes fairly quickly cannot be used to store food for example, as it would just mix with the food. And anything that is stable enough to store food does not decompose in a hundred years or so.

I guess that's part of the reason they're exploring coatings - something to slow down the degradation during regular usage.
- Then you can just used coated cardboard
Sounds great for non-food packages, such as small electronics, toys, etc. Anything that currently comes in a blister pack.
- Depends on how much the salt content in the air at coastal places affect it. But if it doesn't that much, then sure, sounds good. Of course, also the intermediate products of decomposition should be nontoxic in that case.
Product packaging for non-foods

huh. happy to know we'll never hear from this again! thanks capitalism!

Nice!