Japanese scientists create new plastic that dissolves in saltwater overnight

Science article also has some test apparatus images, heat processed finished plastic images, and images of the plastic under attack by several different solvents (hexane, CH2Cl2, THF, Acetone, MeOH, DMF).

Also has stress-strain curves of the material, and behavior when used in glued together boxes for packaging.

Generally, if it actually gets made in quantity, seems like it would be an improvement for somewhere like Japan. Last time I read about Japan on this type of subject, it was examining the outlets of metropolitan streams, and the huge quantities of trash that people just wash down to the oceans. (Notably, from the perspective of considerate people trying to figure out ways to keep the beaches clean and deal with the upstream polluters).

Your remark hints at the fundamental problem with plastics: lifespan and chemical resistance. We worked so hard to develop plastics which have a long lifespan and high chemical resistance which makes them extremely versatile for containers and structures we don’t want to fall apart on their own.

At the same time, it’s these exact same properties of plastics which make them non-biodegradable and resistant to being broken down by the human body’s immune system and waste removal processes. The advantages we developed them for are also the disadvantages we’re trying to replace them for.

In the end, what we truly want is a product that lasts as long as we want and no longer. Something that’s indestructible while it’s in use but can be decomposed and recycled instantly with the push of a button. This is a paradox!

> There’s one major hurdle with any degradable plastic material of course: what if it comes into contact with the catalyst for its destruction before you want it to? A plastic cup is no good if certain liquids can dissolve it, after all.

> In this case, the team found that applying hydrophobic coatings prevented any early breaking down of the material. When you eventually want to dispose of it, a simple scratch on the surface was enough to let the saltwater back in, allowing the material to dissolve just as quickly as the non-coated sheets.

The primary mechanism for this to work is similar to “paper” straws

The product is coated in hydrophobic forever chemicals which protect the material ‘long enough’ before the core is compromised.

It would at least be useful for food delivery, since the packaging on that doesn't need to last more than a few hours tops.

Also human hand sweat has both salt and water so anything that requires a human to carry them might not be suitable.

Plastic should not be used as food packaging.

If an alternative is more expensive, it seems like we should at least consider whether it’s also wasting more resources? I would want to see the comparison done well, rather than simply assuming that plastic must be worse.

> If a solution like this can reduce global hard plastic usage by even 1%, that would be a massive impact.

I would understand if it reduces plastic pollution, but how could it reduce usage?

That's because this news is reported the same way that new battery breakthroughs are reported.

Creating a material in a lab is far from mass production and field testing.

> Dissolving overnight would probably be way too fast.

They addressed that issue, it's in the article.

Simply wrap it in a protective plastic packaging.

> medical equipment

This will be perfect for IV bags!

Making plastics out of sodium, phosphorus, and guanidinium ions [1] which the link characterizes as a "strong organic base", which is designed to break down and so will do so not just in the ocean, suggests to me that there are enough engineering disadvantages the article is not talking about that we'll probably never see this in real life.

It's chemically quite distant from traditional plastics.

The ocean may not care about some extra sodium and phosphorus... and then again, if we made enough, maybe it would... but I'll graciously assume for now it wouldn't, but the other places this would inevitably end up breaking down would probably not appreciate the resulting mess. I have to imagine any quantity of this in a fire near humans would be a fairly substantial problem of some sort. I don't know exactly what would pop out but it's got some awfully "exciting" feedstock going in to it with that sodium and phosphorus.

[1]: https://pubchem.ncbi.nlm.nih.gov/compound/guanidinium#sectio...

The guys marketing these things are really hoping that you have forgotten the law of conservation of mass.

The ultimate problem with these dissolving plastics is that they are still plastic after they dissolve, it's just that they are invisible microplastics instead of visible objects. They largely aren't captured at WWTP and end up in the water supply.

Realistically? Taxes and tax enforcement. That’s really the only consistent and persistent way to change the incentives of the world’s economies. In most developed economies, the ultra wealthy are able to avoid paying their fair share, and the same goes for large corporations as well.

Without fairness, there’s really no easy way to talk about strategy.

I dunno, I am sure the plastic industry would be thrilled to be able to get around environment concerns.

Probably the same thing that kills everything- cost and/or durability/usability.

This isn't game changing? We ALREADY have biodegradable containers that degrade in salt water overnight and can be prevented from degrading with a coating that can then be breached by a scratch:

It's called paper. I've used paper products with a hydrophobic coating (which means plastic, consumers don't like wax coatings that much) for decades. They don't solve the problem, because the plastic coating still fills us with microplastics.

Maybe it cuts down on how much plastic is produced and thrown away, but we could have done this 20 years ago!

There's no conspiracy thwarting "game changing" research to maintain some status quo, though there ARE often political factions who push for maintenance of the status quo.

This is marketing. The people who write this stuff are marketers and they usually don't understand the research in the first place!

This is why, despite everyone insisting that there are hundreds of "This will revolutionize batteries" that everyone complains never materialize, we have actually seen them materialize as lithium batteries like doubling in capacity over a decade. The marketing material overpromised, though the research was fruitful.

Because it's marketing.