How to turn waste polyethylene into something useful

https://www.economist.com/science-and-technology/2022/09/29/how-to-turn-waste-polyethylene-into-something-useful

by helsinkiandrew • 4 years ago

19 7 4 years ago

economist.com

helsinkiandrew• 4 years ago

https://archive.ph/APj04

apple314159• 4 years ago

A better link is https://www.science.org/doi/10.1126/science.add1088

BMc2020• 4 years ago

I saw it being done at a hackerspace (it's the plastic in the clear part of a two liter bottle). Basically melt it into whatever shape you want (you'll be building tooling, frames, extruders, what have you.

On caveat is you need clean polypro, not used 2 liter bottles. It's not hard to get for free though, hospitals discard mountains of it.

namibj• 4 years ago

No, the normal bottle are PET, not PE. PE is somewhat waxy, while PET is more glassy.

walterbell• 4 years ago

Plastic is not cheap when you need it, e.g. coroplast sheets ($15 for 24"x36") or 4# closed-cell polyethylene foam ($20 for 12"x24"x0.5").

benj111• 4 years ago

That's true for a lot of things.

See how much a cardboard box costs when you want to buy one, even though they give them away at the supermarket.

westurner• 4 years ago

From "Argonne invents reusable sponge that soaks up oil, could revolutionize oil spill and diesel cleanup" (2017) https://www.anl.gov/article/argonne-invents-reusable-sponge-... :

[...] The scientists started out with common polyurethane foam, used in everything from furniture cushions to home insulation. This foam has lots of nooks and crannies, like an English muffin, which could provide ample surface area to grab oil; but they needed to give the foam a new surface chemistry in order to firmly attach the oil-loving molecules.
Previously, Darling and fellow Argonne chemist Jeff Elam had developed a technique called sequential infiltration synthesis, or SIS, which can be used to infuse hard metal oxide atoms within complicated nanostructures.
After some trial and error, they found a way to adapt the technique to grow an extremely thin layer of metal oxide “primer” near the foam’s interior surfaces. This serves as the perfect glue for attaching the oil-loving molecules, which are deposited in a second step; they hold onto the metal oxide layer with one end and reach out to grab oil molecules with the other.
The result is Oleo Sponge, a block of foam that easily adsorbs oil from the water. The material, which looks a bit like an outdoor seat cushion, can be wrung out to be reused—and the oil itself recovered.
At tests at a giant seawater tank in New Jersey called Ohmsett, the National Oil Spill Response Research & Renewable Energy Test Facility, the Oleo Sponge successfully collected diesel and crude oil from both below and on the water surface.

From "Reusable Sponge for Mitigating Oil Spills" https://www.energy.gov/science/bes/articles/reusable-sponge-... :

A new foam called the Oleo Sponge was invented that not only easily adsorbs oil from water but is also reusable and can pull dispersed oil from an entire water column, not just the surface. Many materials can grab oil, but there hasn't been a way, until now, to permanently bind them into a useful structure. The scientists developed a technique to create a thin layer of metal oxide "primer" within the interior surfaces of polyurethane foam. Scientists then bound oil-loving molecules to the primer. The resulting block of foam can be wrung out to be used, and the oil itself recovered.

How to turn waste polyethylene into something useful

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