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Disclaimer: So I have a PhD in mtls science, and I studied a bit of plastics thermo. However I never worked on the recycling problem. Plastics, or polymers th

Disclaimer: So I have a PhD in mtls science, and I studied a bit of plastics thermo. However I never worked on the recycling problem. Plastics, or polymers that aren’t cross linked, are in a sense easy to recycle - Just melt them and recast the part. 3D printing hobbyists even recycle their filament. The problem is that any melted plastic doesn’t mix with any plastic other than itself. So if you have 99% polyethylene and 1% polypropylene and melt them together they won’t mix. But they won’t separate perfectly either (so you can’t skim the PP put). Instead you get inter-penetrating phases (a spinodal). These phases have surfaces that don’t stick well together so the end result is that any parts made of this are exceptionally weak. So this is the dilemma: if you have even 1% of different polymer in your mix, the plastic will suck. But we use at least 4 or 5 different plastics in everyday life all chucked into the same bins, all looking more less the same. Solutions? 1. One solution is to heat all the plastics so that they break apart and therefore use them for feedstock. But this is very expensive, and the feedstocks aren’t very pure. 2 Make cat fuel. Cheaper then above, since the purity requirements aren’t as strong, but it’s basically the same as number 1. This doesnt increase CO2 emissions since the plastic is displacing oil 3. Burn it for energy. This needs far less strict requirements than 2 and lower CO2 emissions (since you don’t have to waste energy getting oil out). However, you’d have to basically ban public use of perfluorinated polymers or make them very expensive, or make them easy to identify (Teflon, gore-Tex.) Frankly I’d ban perfluorinates except for use in critical industries. That chemistry is ecologically nasty. 4. Force companies to color their containers according to plastic type. I.e no more clear Pepsi or Coke bottles - all PE products are color, say green. All PP colors are red, etc.

tesseract 6y ago
This is likely a dumb outsider viewpoint but: is just burying plastics all that bad? The fact that they stay intact over geologic timescales would seem to make them an ideal carbon sink, which is something we could actually use more of - provided that feedstocks can come out of the carbon cycle (e.g. agricultural) rather than relying on petrochemicals.
- throwmtlsPhD 6y ago
  I like your comment and the honest answer is I don’t know, but I see no problems with dumping plastic on the ground, vs in the ocean. But some observations on your comment. Is plastic, that was never in the atmosphere (for millions of years anyway), really a carbon sink? It seems that trough its entire lifecycle it never goes into the atmosphere. Also, if you burn plastic you’re displacing oil that wouldn’t otherwise be burned. Oil that is never extracted. And don’t forget that it takes a lot of energy to extract oil, so burning plastic reduces CO2 emissions globally somewhat. Also, I’m skeptical about the practicality of using landfills to create geological treasures for mankind 100k years from now. The problem with it is that I feel that it is wishful thinking that placates our conscience. It’s easy to imagine yourself living “sustainably” in geological time scales. It’s hard to live sustainably in 1000 year timescales.
  - lupire 6y ago
    The problem with burying plastic is that there's no room to do that locally, so you have to send it somewhere. Burning is the only thing that makes sense, and that's OK if thebtotalt amount is "not too much", where current fossil fuel usage is "too much".
    - deleted 6y ago
      [deleted]
- WheelsAtLarge 6y ago
  Waste plastic has a negative value, right now. I think that burying it is even more expensive than to just dump it where ever it's possible, in some places. It may not be legal but as always if people can make a buck then they will. Laws or no laws. It turns out that a lot of the plastic in the ocean is there because there are countries where people are just dumping trash in the ocean. It can be less expensive than transporting it to a dump and dealing with it there. The answer has to include making waste plastic have enough value so that people find it advantageous to recycle it or at least to bury it.
- HDMI_Cable 6y ago
justinpombrio 6y ago
This is a great comment. > 4. Force companies to color their containers according to plastic type. I.e no more clear Pepsi or Coke bottles - all PE products are color, say green. All PP colors are red, etc. Humans don't have to sort the plastics, machines could. Is there a machine-readable but human-invisible marking we could give them? Like coloring them in a way that would be distinctive under a UV camera or UV light?
- lupire 6y ago
  If it's transparent, you've lost "color" control. But maybe some kind of radar/sonar-type response signature could work
  - throwmtlsPhD 6y ago
    It can be transparent in the visible spectrum. But ya, the UV dyes are probably not very stable
- spreadsheetuser 6y ago
  In my not-so-professional opinion, IR and Raman spectrography could give us something. Or density, depending on how selectively the industrialized mechanical processes are at resolving small changes in physical properties.
- Dolores12 6y ago
  RFID chip maybe?
  - labawi 6y ago
    Convert plastic waste into e-waste?
    - efreak 6y ago
      From Wikipedia: > Hitachi holds the record for the smallest RFID chip, at 0.05 mm × 0.05 mm......These dust-sized chips can store 38-digit numbers using 128-bit Read Only Memory (ROM). A major challenge is the attachment of antennas, thus limiting read range to only millimeters. Sounds to me like RFID chips can be small enough to not worry about. Even at 1mm^3, you can likely just let it fall out while melting down plastic, and collect it later. Not that I'm advocating for doing so, I think enforcing a visible symbol indicating the contents is a far better idea.
merb 6y ago
> 4. Force companies to color their containers according to plastic type. I.e no more clear Pepsi or Coke bottles - all PE products are color, say green. All PP colors are red, etc. well I'm no expert in this topic, just a little bit more engaged with the topic. the biggest problem is that companies save tons of money not from different colors, but from different components. most cheese products for example have different types of plastic (MA/MH packaging, compound structure plastics are just cheap and easy to do), and most people do not know that if you don't separate them that it is way harder to recycle (some also just don't care). it's a hard topic and I've seen countries like sweden who tackle that problem by teaching everybody how to recycle plastics (they have multiple containers), but I do not thing that this is feasible worldwide. I mean I live in germany and my governement does not tackle the problem, they do not invenst, they do not regulate, all they do is calling itself "world champion of recycling", but what do they do? they declare burning waste as recycling (called thermetic recycling, point 3. but it's not recycling and we do not care about the emission when it comes to burning) or better, we declare it as recycled but ship it to africa / asia and don't look what they do with the waste at all. waste management is something that most countries don't feel pressured to change something. mostly because you would need to change multiple industries, the packaging industry and the waste management industry. > Frankly I’d ban perfluorinates except for use in critical industries. That chemistry is ecologically nasty. well a lot of things are nasty, but as long as they print money. it won't be banned/changed that fast.
- throwmtlsPhD 6y ago
  Excellent point about the multiple components in products. Ppl don’t realize that there’s a plastic liner on their can of Coke (of course, that just gets burned off when the Al gets recycled) About Germany’s “recycling” I despise it when “experts” talk down at ppl saying “white lies” because we’re too stupid to understand (Dr. Fauci, I’m looking at you buddy). Burning plastic isn’t recycling and Germany’s neologism is sophistry. But it is a decent solution short of significantly increasing the price of plastic. That’s assuming you burn it correctly. And correctly burning it requires very high temperatures to get rid of dioxins. It means making sure to reduce as much as possible Chlorine sulphuric and Fluorine in the feedstock. It means having excellent NOx filters. It means having super tough monitoring of the emissions
WheelsAtLarge 6y ago
What's cat fuel? Getting rid of waste plastic in the environment is not impossible. The big problem is that manufactures only pay for the creation of the product. We need to have them pay for the disposal too. In time they will find the least expensive way to recycle it.
- throwmtlsPhD 6y ago
  Typo, car. And for some reason I can’t push edits on my comments
  - jamiek88 6y ago
    Yeah edit ability times out quickly.
    - hilbert42 6y ago
      Yeah, HN's short timeouts are a damn nuisance especially if one's as prolix as me (I've been caught out many times). That said, HN's edit duration is still considerably longer than say The Register's one of only ten minutes. Of course, one should never be one's own editor as one always misses something - that is until one reads it the next day and sees one's glaring typos! But that's impractical. It seems to me that a partial solution would be to allow small/limited edits after the normal timeout and or highlight the changes in some way. This would negate the problem of a subsequent poster's reply comment sounding ridiculous if the original post was altered too much.
  - WheelsAtLarge 6y ago
    Thx, I should have known. For a minute there I thought that it was short for a special type of fuel for machines.
    - samatman 6y ago
      I assumed "cat fuel" was some shorthand for "catalytically cracked fuel" which I simply hadn't heard before. Which actually works, because that's exactly what you'd have to do! https://en.wikipedia.org/wiki/Fluid_catalytic_cracking https://en.wikipedia.org/wiki/Fluid_catalytic_cracking
2muchcoffeeman 6y ago
Why can’t we force containers to be made of the same plastic? Or use a better material, eg aluminium. I’ve seen aluminium bottles with aluminium caps. I realise the lining is plastic, but that little bit of plastic has to be better than a plastic bottle.
xorcist 6y ago
> polymers that aren’t cross linked, are in a sense easy to recycle The way to do big changes is one small step at a time, and the reasonable way is to start with the low hanging fruit. So the the interesting question isn't why we're being lied to by Big Recycling, but why the easiest steps aren't being taken. It's almost fruitless to discuss these issues on online forums because otherwise intelligent people insists on explaining how hard the problem of universal polymer recycling really is, as if that would make all recycling of plastics (sometimes even all recycling, full stop) impossible. Meanwhile countries such as Norway recycles 95% av all PET bottles while the US is stuck on 30%. Yet every discussion that remotely touches on recycling has to iterate that it's all a big lie.

tesseract 6y ago

This is likely a dumb outsider viewpoint but: is just burying plastics all that bad? The fact that they stay intact over geologic timescales would seem to make them an ideal carbon sink, which is something we could actually use more of - provided that feedstocks can come out of the carbon cycle (e.g. agricultural) rather than relying on petrochemicals.

throwmtlsPhD 6y ago
I like your comment and the honest answer is I don’t know, but I see no problems with dumping plastic on the ground, vs in the ocean. But some observations on your comment. Is plastic, that was never in the atmosphere (for millions of years anyway), really a carbon sink? It seems that trough its entire lifecycle it never goes into the atmosphere. Also, if you burn plastic you’re displacing oil that wouldn’t otherwise be burned. Oil that is never extracted. And don’t forget that it takes a lot of energy to extract oil, so burning plastic reduces CO2 emissions globally somewhat. Also, I’m skeptical about the practicality of using landfills to create geological treasures for mankind 100k years from now. The problem with it is that I feel that it is wishful thinking that placates our conscience. It’s easy to imagine yourself living “sustainably” in geological time scales. It’s hard to live sustainably in 1000 year timescales.
- lupire 6y ago
  The problem with burying plastic is that there's no room to do that locally, so you have to send it somewhere. Burning is the only thing that makes sense, and that's OK if thebtotalt amount is "not too much", where current fossil fuel usage is "too much".
  - deleted 6y ago
    [deleted]
WheelsAtLarge 6y ago
Waste plastic has a negative value, right now. I think that burying it is even more expensive than to just dump it where ever it's possible, in some places. It may not be legal but as always if people can make a buck then they will. Laws or no laws. It turns out that a lot of the plastic in the ocean is there because there are countries where people are just dumping trash in the ocean. It can be less expensive than transporting it to a dump and dealing with it there. The answer has to include making waste plastic have enough value so that people find it advantageous to recycle it or at least to bury it.
HDMI_Cable 6y ago

justinpombrio 6y ago

This is a great comment. > 4. Force companies to color their containers according to plastic type. I.e no more clear Pepsi or Coke bottles - all PE products are color, say green. All PP colors are red, etc. Humans don't have to sort the plastics, machines could. Is there a machine-readable but human-invisible marking we could give them? Like coloring them in a way that would be distinctive under a UV camera or UV light?

lupire 6y ago
If it's transparent, you've lost "color" control. But maybe some kind of radar/sonar-type response signature could work
- throwmtlsPhD 6y ago
  It can be transparent in the visible spectrum. But ya, the UV dyes are probably not very stable
spreadsheetuser 6y ago
In my not-so-professional opinion, IR and Raman spectrography could give us something. Or density, depending on how selectively the industrialized mechanical processes are at resolving small changes in physical properties.
Dolores12 6y ago
RFID chip maybe?
- labawi 6y ago
  Convert plastic waste into e-waste?
  - efreak 6y ago
    From Wikipedia: > Hitachi holds the record for the smallest RFID chip, at 0.05 mm × 0.05 mm......These dust-sized chips can store 38-digit numbers using 128-bit Read Only Memory (ROM). A major challenge is the attachment of antennas, thus limiting read range to only millimeters. Sounds to me like RFID chips can be small enough to not worry about. Even at 1mm^3, you can likely just let it fall out while melting down plastic, and collect it later. Not that I'm advocating for doing so, I think enforcing a visible symbol indicating the contents is a far better idea.

merb 6y ago

> 4. Force companies to color their containers according to plastic type. I.e no more clear Pepsi or Coke bottles - all PE products are color, say green. All PP colors are red, etc. well I'm no expert in this topic, just a little bit more engaged with the topic. the biggest problem is that companies save tons of money not from different colors, but from different components. most cheese products for example have different types of plastic (MA/MH packaging, compound structure plastics are just cheap and easy to do), and most people do not know that if you don't separate them that it is way harder to recycle (some also just don't care). it's a hard topic and I've seen countries like sweden who tackle that problem by teaching everybody how to recycle plastics (they have multiple containers), but I do not thing that this is feasible worldwide. I mean I live in germany and my governement does not tackle the problem, they do not invenst, they do not regulate, all they do is calling itself "world champion of recycling", but what do they do? they declare burning waste as recycling (called thermetic recycling, point 3. but it's not recycling and we do not care about the emission when it comes to burning) or better, we declare it as recycled but ship it to africa / asia and don't look what they do with the waste at all. waste management is something that most countries don't feel pressured to change something. mostly because you would need to change multiple industries, the packaging industry and the waste management industry. > Frankly I’d ban perfluorinates except for use in critical industries. That chemistry is ecologically nasty. well a lot of things are nasty, but as long as they print money. it won't be banned/changed that fast.

throwmtlsPhD 6y ago
Excellent point about the multiple components in products. Ppl don’t realize that there’s a plastic liner on their can of Coke (of course, that just gets burned off when the Al gets recycled) About Germany’s “recycling” I despise it when “experts” talk down at ppl saying “white lies” because we’re too stupid to understand (Dr. Fauci, I’m looking at you buddy). Burning plastic isn’t recycling and Germany’s neologism is sophistry. But it is a decent solution short of significantly increasing the price of plastic. That’s assuming you burn it correctly. And correctly burning it requires very high temperatures to get rid of dioxins. It means making sure to reduce as much as possible Chlorine sulphuric and Fluorine in the feedstock. It means having excellent NOx filters. It means having super tough monitoring of the emissions

WheelsAtLarge 6y ago

What's cat fuel? Getting rid of waste plastic in the environment is not impossible. The big problem is that manufactures only pay for the creation of the product. We need to have them pay for the disposal too. In time they will find the least expensive way to recycle it.

throwmtlsPhD 6y ago
Typo, car. And for some reason I can’t push edits on my comments
- jamiek88 6y ago
  Yeah edit ability times out quickly.
  - hilbert42 6y ago
    Yeah, HN's short timeouts are a damn nuisance especially if one's as prolix as me (I've been caught out many times). That said, HN's edit duration is still considerably longer than say The Register's one of only ten minutes. Of course, one should never be one's own editor as one always misses something - that is until one reads it the next day and sees one's glaring typos! But that's impractical. It seems to me that a partial solution would be to allow small/limited edits after the normal timeout and or highlight the changes in some way. This would negate the problem of a subsequent poster's reply comment sounding ridiculous if the original post was altered too much.
- WheelsAtLarge 6y ago
  Thx, I should have known. For a minute there I thought that it was short for a special type of fuel for machines.
  - samatman 6y ago
    I assumed "cat fuel" was some shorthand for "catalytically cracked fuel" which I simply hadn't heard before. Which actually works, because that's exactly what you'd have to do! https://en.wikipedia.org/wiki/Fluid_catalytic_cracking https://en.wikipedia.org/wiki/Fluid_catalytic_cracking

2muchcoffeeman 6y ago

Why can’t we force containers to be made of the same plastic? Or use a better material, eg aluminium. I’ve seen aluminium bottles with aluminium caps. I realise the lining is plastic, but that little bit of plastic has to be better than a plastic bottle.

xorcist 6y ago

> polymers that aren’t cross linked, are in a sense easy to recycle The way to do big changes is one small step at a time, and the reasonable way is to start with the low hanging fruit. So the the interesting question isn't why we're being lied to by Big Recycling, but why the easiest steps aren't being taken. It's almost fruitless to discuss these issues on online forums because otherwise intelligent people insists on explaining how hard the problem of universal polymer recycling really is, as if that would make all recycling of plastics (sometimes even all recycling, full stop) impossible. Meanwhile countries such as Norway recycles 95% av all PET bottles while the US is stuck on 30%. Yet every discussion that remotely touches on recycling has to iterate that it's all a big lie.