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> The technique involves heating ordinary plastics such as bottles or shopping bags and then putting them into an ordinary cotton candy machine (also known as a
by vanderZwan 6y ago
> The technique involves heating ordinary plastics such as bottles or shopping bags and then putting them into an ordinary cotton candy machine (also known as a candy floss machine). The machine spins the plastic into a material that is similar to cotton candy (a mesh), which is also electrocharged by the spinning.
I'm always sceptical of these kind upcycling plastic narratives that involve melting them, since apparently a lot of plastics only are labeld safe under the assumption that they don't get heated until the melting point. After that they may start leaking chemicals, a bit like the whole non-stick coating story.
But if the source of plastic is reliable then this sounds pretty good.
- prvc 6y agoI think they just meant that bottles and shopping bags are made from "ordinary plastics".
- abdullahkhalids 6y agoFrom the abstract > The input polymer is polypropylene or polystyrene, and can include discarded plastic containers of these materials, ... https://royalsocietypublishing.org/doi/full/10.1098/rspa.2020.0469 https://royalsocietypublishing.org/doi/full/10.1098/rspa.202...
- kps 6y agoMarked and respectively. Edit: U+2677 and and U+2678. Obviously no one would ever want to write about plastics on HN, so it's totally OK to strip those symbols.
- _Microft 6y agoBefore you spend time looking this up, this is it: U+2677 is the recycling symbol type 5 (polypropylene/"PP") and U+2678 is recycling material type 6 (polystyrene/"PS"). https://en.wikipedia.org/wiki/Recycling_codes#List_of_resin_identification_codes_(RIC)_and_codes_defined_by_the_European_Commission https://en.wikipedia.org/wiki/Recycling_codes#List_of_resin_...
- maxerickson 6y agoThere are different sorts of plastics. Thermoplastics can melt without undergoing any chemical changes: https://en.wikipedia.org/wiki/Plastic#Thermoplastics_and_thermosetting_polymers https://en.wikipedia.org/wiki/Plastic#Thermoplastics_and_the... Most packaging is thermoplastic.
- kube-system 6y agoSome thermoplastics have additives, not chemically part of the base material, which can leach out.
- vanderZwan 6y agoYeah, this is what I meant. For example the paint in colored plastics. Which is why all those colorful "upcycled" food bowls from plastic fantastic kind of worry me. To be clear: I don't know if the paint in plastic is dangerous, the problem is that I also don't know if they're not. It feels like the kind of area where even without bad intentions/incentives, the people who made the plastics or who set up the regulations for them might have assumed there is no real risk, because nobody planned for this type of plastic recycling.
- awakeasleep 6y agoPlastic (the noun) isn't plastic (the adjective) Pure 'plastic' polymer- be it nylon, polyethylene terephthalate, Acrylonitrile Butadiene, pvc- anything! Is generally a brittle, almost powdery material, that is of no use to anyone. I'd say they range in texture from something like . What we think of as 'plastic' - what we experience and use as a product or a material, is a cocktail of polymer, 'plasticizers', chain extenders, cross linkers, and other chemicals. Trying to come up with an analogy, I'd almost say polymers:flour::plastic::cake
- adrianmonk 6y agoCould still be useful in poor countries where the pandemic is a greater risk.