ESA - Greener polyurethanes for space and beyond

[southwestforests]

Perhaps of related interest?
https://www.esa.int/Enabling_Support/Sp ... and_beyond

Have you heard of polyurethanes? As you read this, you’re undoubtedly close to some, or maybe sitting on them: this versatile class of chemicals is used for everything from padding your couch to insulating your windows, packaging food to carpet underlay, electronics casings to skateboard wheels. They also have vital uses in space, triggering a new ESA Clean Space project aiming to manufacture them in a greener way.

The space sector relies on them for coating and securing (or ‘potting’) electronic components, limiting their ‘outgassing’ of potentially harmful vapours in the vacuum of space and stopping any damage during launch. And every launcher to lift off carries a few kilograms of polyurethanes in the form of foam used to insulate cryogenic propellant tanks.

[Cralis]

Definitely interesting. Removing toxic chemicals from a process is always important because it makes manufacturing cheaper and faster by reducing overhead in the form of safety equipment and cleanup. Though I noticed that the article was very careful to say that the results are "chemically nearly identical" without making any kind of comparison on actual effectiveness...

But definitely interesting.

[southwestforests]

Definitely interesting. Removing toxic chemicals from a process is always important because it makes manufacturing cheaper and faster by reducing overhead in the form of safety equipment and cleanup.

Not having been much involved in manufacturing during my working years, I hadn't thought of that.

Which is kind of interesting since I did work in health care, hobby retail, art supply retail, automobile retail, and ALL of those involve the usage or selling of, and the potential cleanup of, hazardous materials & we had to have and know about supplies for that cleanup.

[Cralis]

A good personal example of this was a battery that I tested when I was in the service. It was a zinc-air battery... apparently something widely used these days. This specific one was lighter (though physically larger), had a much higher energy density, and had to be blown apart to stop working. If you got it wet, you let it dry and it kept working (try that with lithium-ion, go ahead, I'll wait). It was completely non-toxic, so it didn't require special storage or cost to dispose.

I always wondered if my old unit ever started using them. Seemed like a pretty good deal to me.

[southwestforests]

A good personal example of this was a battery that I tested when I was in the service. It was a zinc-air battery... apparently something widely used these days.

Though widely used it is outside of what my life comes across and I was not familiar with that battery type so I went Googling.

Hmm ...

https://science.sciencemag.org/content/371/6524/46

Research Article
A rechargeable zinc-air battery based on zinc peroxide chemistry

View ORCID Profile Wei Sun1, View ORCID Profile Fei Wang2,*, View ORCID Profile Bao Zhang3, View ORCID Profile Mengyi Zhang1, View ORCID Profile Verena Küpers1, View ORCID Profile Xiao Ji4, View ORCID Profile Claudia Theile1, View ORCID Profile Peter Bieker1, View ORCID Profile Kang Xu5,*, View ORCID Profile Chunsheng Wang4,6,*, View ORCID Profile Martin Winter1,7,*

See all authors and affiliations
Science 01 Jan 2021:
Vol. 371, Issue 6524, pp. 46-51
DOI: 10.1126/science.abb9554

When two is better than four

Batteries based on the reaction of zinc and oxygen have been used for more than a century, but these have been primary (that is, nonrechargeable) cells. These batteries use an alkaline electrolyte and require a four-electron reduction of oxygen to water, which is a slow process. Sun et al. show that with the right choice of nonalkaline electrolyte, the battery can operate using a two-electron zinc-oxygen/zinc peroxide chemistry that is far more reversible. By making the electrolyte hydrophobic, water is excluded from the near surface of the cathode, thus preventing the four-electron reduction. These batteries also show higher energy density and better cycling stability.

Science, this issue p. 46

[Cralis]

Huh, didn't know there were rechargeable versions. The ones we used were not... it didn't matter because they could be thrown out in a trash can (we didn't, we recycled them, but the point about non-toxicity stands).