Post AmJ12BmO41crQCPCaW by feld@friedcheese.us
 (DIR) More posts by feld@friedcheese.us
 (DIR) Post #AmJ129iPjpG91IX07M by Elucidating@mastodon.social
       2024-09-23T18:34:31Z
       
       0 likes, 0 repeats
       
       Quick reminder as you see the news float by today: most 3d printers tend to use specific non-industrial plastics made from agricultural byproducts. These have entirely different characteristics than the industrial plastics you see.Some 3d printing is done with other plastics, and you should try to avoid buying products made with PET or PETG, ASA, and ABS. These materials are not substantially better than PLA for non-industrial use (e.g., their glass transition is higher but not much).
       
 (DIR) Post #AmJ12AZaY7nHgDPT04 by Elucidating@mastodon.social
       2024-09-23T18:36:32Z
       
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       There are plastics that do not induce demand for oil, can break down in the environment, and have higher glass transition temperatures. But the demand for them is too low, and so they never leave the lab. (Please note: this refers to novel plastics, PLA is industrially compostable and has a better long term breakdown story than most thermoplastics, but is old tech)We can change that by demanding which plastics are used and rejecting the idea that recycling is a valid solution to the problem.
       
 (DIR) Post #AmJ12BASL3HhWYeuSu by feld@friedcheese.us
       2024-09-23T19:06:05.236989Z
       
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       @Elucidating > can break down in the environmentHighly skeptical. You mean the types that make nanoplastics instead of microplastics? Can you cite an example?edit: wait, you are talking about PLA it just wasn't clearbut PLA doesn't "break down in the environment". This makes it sound like it's harmless and biodegradable but it's not.e.g.,:PLA is compostable in industrial composting facilities, where they can con-trol the temperature, humidity and environment. The temperature must beat least 60 ℃ and the humidity high for hydrolysis to occur. After this thepolymers can be degraded by microorganism action [9]. In these conditionsthe plastic can be degraded within three months [10]. These conditions arenot likely to occur in the environment, especially not marine or other aque-ous environments. This means that in nature, PLA is not biodegradable andwill degrade through other mechanisms.These mechanisms are photo-, thermal, mechanical and chemical degra-dation. Through these mechanisms micro, and nanoplastics may be formedand released into the environment. One example of mechanical breakdownwould be plastic rubbing against sand on a beach.https://lup.lub.lu.se/luur/download?func=downloadFile&recordOId=9087081&fileOId=9087097
       
 (DIR) Post #AmJ12BmO41crQCPCaW by feld@friedcheese.us
       2024-09-23T19:43:55.318214Z
       
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       @Elucidating I'd be willing to be that PLA plastics are *worse* for the environment because it gets brittle over time and has lower thermal stability than ABS
       
 (DIR) Post #AmJ12CXtDPchnWd8d6 by Elucidating@mastodon.social
       2024-09-23T19:46:36Z
       
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       @feld No. That's ridiculous. What the actual fuck are you talking about?Edit: nevermind. I will post the link later. I'm going to take care of work and mute you becuse that's such an outrageously unsupportable position I never want to hear from you again.
       
 (DIR) Post #AmJ12CyTcYtH7z4N4S by feld@friedcheese.us
       2024-09-23T19:57:12.172482Z
       
       1 likes, 0 repeats
       
       @Elucidating maybe you should learn about how plastics are actually made before getting on the train of PLA because "no oil". We don't make oil to make plastics.> Although crude oil is a source of raw material (feedstock) for making plastics, it is not the major source of feedstock for plastics production in the United States. Plastics are produced from natural gas, feedstocks derived from natural gas processing, and feedstocks derived from crude oil refining.It is a free *byproduct* of refining that would otherwise have to be dealt with as industrial waste, but instead they figured out how to make it into plastic and sell it to us.https://www.eia.gov/tools/faqs/faq.php?id=34&t=6There is never going to be a plastic that is safe for the environment. PLA is derived from corn and you do NOT want to go down that road... we should not be growing fucking corn to make plastic. Like holy shit new levels of stupidity... Guess how they grow that corn? With tons and tons of synthetic fertilizerGuess where the fertilizer comes from? OIL AND GAS