Straw Based Filament?

Straw Based Filament

PLA (polyactic acid) is often toted as one of the most environmentally friendly and safe filaments for consumer printing, since it is derived from corn products — not fossil fuels. But there’s a new contender on the market, and that is a type of straw-based plastic filament — which also promises to cost around half as much!

Designed by a Chinese company called Jinghe, the material is made by grinding up various dried crops like wheat, rice, and cotton, which in China is typically burned to get dispose of. The sawdust is then mixed with additives like polypropylene, silane coupling agent, and ethylene bis(stearamide). It is then extruded into a pellets of uniform size to allow for easier processing. From there it can be used for injection molding (melting temperature between 160-180°C), or further extruded into filament form. The filament  and resulting prints are a woody color with an interesting fiber-like surface finish, with decent part strength.

The company has signed a $320,000 USD contract with the Shantou city government to produce this type of plastic for toys in the European market — If production ramps up, it could well become one of the cheapest filaments available!

We like to cover all these alternative filaments as they come out, and there is becoming quite a selection! If you hear of any new materials used for printing, don’t forget to send them in to the tips line!

[Via 3ders.org]

Comments

  1. Parko says:

    Next stop; hemp based filament aka the stuff used to make car panels pre prohibition

    • qwertyuiop says:

      When’s that piratebay island finally going to materialize? :D

      • srgjkop says:

        Hemp based printing is an awesome idea! You could 3D-print joints in any shape imaginable. You could even print with hashish.

        • Professr says:

          Another wonderful individual who does not understand the difference between hemp (can’t get you high) and marijuana (can get you high)

          • Ren says:

            It is only a semantic difference created by pro-pots to ease the mind of the uneducated populace.

          • Dax says:

            No it isn’t. The hemp producing variants are selectively bred to produce fiber, which is antagonist for the cannabinoid production.

            Meanwhile the strains that are bred to produce the drug are rather poor at producing useful fibers because they’re bred to produce the resin that contains the cannabinoids.

        • Blue Footed Booby says:

          @Ren
          Actually the opposite. You get high from the buds. You make hemp from the stalks, which have trivial amounts of THC by any honest measure. Opposition to hemp is basically entirely an outgrowth of puritanical anti-drug zealotry and the ignorance caused by it.

          I say this as someone who has never used marijuana, has no interest in ever doing so, and honestly doesn’t think too much of most regular users encountered thus far.

          • Ren says:

            I’m accepting your correction, my comment should’ve said (as you’ve stated)
            It’s the SAME plant!
            It is a smoke and mirrors thing foisted on the public
            Hemp = good
            MaryJane != good
            so we’ll tell everyone that we just want to raise hemp.

          • Dax says:

            It’s the same plant, but different breed. Especially in the northern climates, Cannabis Ruderalis had been used as a source of fiber because the other variants don’t grow as well there, whereas the drug version comes from the south and is called Cannabis Sativa or Indica.

            None of the three variants make very much cannabinoids in the wild, and Ruderalis makes so little even under optimal conditions that it’s not worth the bother to grow it as a drug. It’s been crossbred with Sativa and Indica though to create autoflowering versions that are short and stout and produce tons of cannabinoids to be grown in people’s closets and attics etc.

  2. Andrew says:

    PLA is ‘polylactic acid’.

    And this “…which in China is typically burned to get dispose of.” makes no sense.

    • Tony says:

      It’s not PLA, or if it is then it’s made from a cheaper source material. So rather than use corn, they use the corn stalks instead (which is waste).

      And that’s what they’re burning, the stuff left over after you pick the corn. Or whatever (wheat, sugar, etc).

      Most readers here know that HAD and editing are a foreign concept, and as written they’re saying the Chinese usually burn the crops (which yeah kinda defeats the purpose) but TFA does get it right (burning the crop waste).

      • Ren says:

        Even then, burning biomass adds to atmospheric CO2, and it could just as well be composed.

        • Jimbo whales says:

          Actually no, during composting, the bulk of the carbon is broken down into methane and carbon dioxide. Even material taken up by organisms will ultimately exit and enter the air via the carbon cycle, just a bit slower. Now if you converted all the waste to charcoal pellets and then buried them for good, that would work.

          • Dax says:

            Turning biomass into charcoal and then burying it is called Terra Preta, and it’s a known soil improvement method because the charcoal retains nutrients and water better than the inorganic dirt and it isn’t subject to biological decomposition because microbes can’t eat straight up carbon.

            It’s been hypothesized that most of our fertile topsoil is actually a product of frequent forest fires.

        • Luke says:

          Burned crop mass produces no net CO2, since the next crop grown re-absorbs the CO2. I assume you mean “composted” – that also produces CO2 (also zero net).

          Burning, however, produces soot and other pollutants, which is not a great idea.

          • Dax says:

            Burning biomass does shift the carbon balance from biomass to the atmosphere because the carbon spends less time as a plant or plant remains, and more time as free CO2 gas in the air.

        • Tony says:

          Yes, but the point is they’ll stop burning it and turn it into plastic instead.

          Now we can sequester carbon into millions of rolls of filament hidden under nerds desks: “we’ll, I’ll build that 3D printer one day…”

  3. daid303 says:

    The price of filament is not in the raw material costs, pellets of PLA only cost around 5 euro per kg, while filament costs between 30 and 40 euro per kg.

  4. yosh says:

    I wonder how it would fare in production of hats?

  5. Ren says:

    Okay actual or armchair chemists…
    So the corn/oats/straw/whatever easily decomposes, but what about the binder chemicals?

    • rj says:

      Polypropylene isn’t particularly biodegradable, but it’s a very nice plastic.
      Ethylene bis(stearamide) is a long nonpolar molecule with a highly polar core, and is not so different from soap.
      A “silane coupling agent” would be the part that concerns me the most; silanes are not particularly nice chemicals. There is a readily-findable article from Gelest about how they’re used in plastics: it’s the first google hit.

      So, in summary, I don’t see this as a plastic that was ever intended to be biodegradable. But my understanding is that usually people don’t print with PLA because it’s biodegradable, but rather because its softening temperature and cost are very convenient for filament.

      In any case, “fine powders mixed into plastic” is something that the plastics industry has been researching for decades now, because it’s a good way to change the mechanical and optical properties more cheaply than using other monomers.

  6. efahrenholz says:

    Decomposing toys…use it or lose it!

  7. Rick says:

    sticky rice to get real sticky!

    trying to find that link of a temple in China that was unearthed where the supports were made of bowls glued together with rice paste. Strong as adobe or cement.

  8. JRDM says:

    It deals with a waste plant product, but binds it in materials that aren’t bio-friendly, so I don’t think it is a clear improvement over PLA, if earth-friendliness is a concern. It might be interesting material to work with though.

    On the cost of filament, pellets can be had in bulk for much less than quoted above. I don’t think commercial filament will get much cheaper unless the production volume goes up a lot. I think the answer is large maker groups building their own extruder & winder is the only short term way to push costs down, and you have to watch your costs in parts, time, & electricity. I think it takes roughly 20 spool’s worth of filament to pay back for the machine, assuming you get usable filament that compares in quality.

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