• TheObviousSolution@lemm.ee
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    4 months ago

    How is it difficult to recycle? The temperatures requires to do so are less than metal, the 3D printing communities has people that recycle them into filaments all the time. I don’t think the problem is the plastic so much as it is how it is still treated as a disposable container and that neither companies nor governments pay for or provide reclamation means like recycling machines that pay for each bottle collected. In other words, the problem is more cultural than material.

    • Eranziel@lemmy.world
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      4 months ago

      Others have pointed out the degradation issue, but you’re also assuming that all plastics are thermoplastics. They are not. There’s huge variation in chemical composition and material properties between different plastics, and most of them can’t be melted and reformed.

      • TheObviousSolution@lemm.ee
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        4 months ago

        But then the problem isn’t with all plastics, it’s with certain plastics, and around 70% of global plastic production are concentrated around commodity plastics, all of which are thermoplastic. The greatest degradation issue occurs with biodegradable plastics, which is perceived as a good thing for them, though even biodegradable PLA has toxicity concerns.

    • HereIAm@lemmy.world
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      4 months ago

      And how many times do they recycle the filament until it’s too degraded to use?

      • TheObviousSolution@lemm.ee
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        4 months ago

        Depends on what you consider degraded, the only reason it would stop being recyclable is if it became too contaminated with foreign substances or exposure, which applies to anything.

        • cynar@lemmy.world
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          4 months ago

          Repeating plastics tends to damage them on a chemical level. The polymer chains break and shorten. This ends with the plastic being more brittle. Since 3d printed parts have already been remelted once, they have even more degradation than injection moulded parts.

          I believe the recommended amount of recycled plastic is around 30% for PLA. Any more and the parts lose significant strength.

          I personally would prefer us to accept that plastics aren’t really recyclable. It’s better to move towards renewable plastics like PLA, and treat the waste as biomass (either composted or burnt for energy.

          • TheObviousSolution@lemm.ee
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            4 months ago

            I personally would prefer us to accept that plastics aren’t really recyclable. It’s better to move towards renewable plastics

            Err … getting mixed signals …

            What you are describing is exposure. There are plenty of build with 100% recycled plastic, so not sure where you are getting that 30%. I think you are perhaps thinking of the marketing material of PLA filaments that sell themselves as particularly ecofriendly because they include recycled materials, while I’m talking about builds made entirely out of things like recycled water bottles, which are made out of PET. PLA is more susceptible to exposure to sunlight, heat, and moisture, so rather than using it to hold beverages at that point you might want to skip plastic entirely. PLA itself is not recycled that much, but it is more biodegradable.

            • cynar@lemmy.world
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              3 months ago

              Exposure can cause similar effects. However, the act of heating the plastic to the temperatures needed to melt it and defirming it also damages the structure. It’s particularly obvious with pla, but all plastics suffer from it, to an extent.