Corn Straw: Break It Down!
By Wesley Joseph • Jun 6th, 2008 • Category: Recycling
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Busting yet another move with the compostable products commentary, has anyone seen corn-based biodegradable plastics? I have seen some plastic items made of corn product, and it feels just like normal, petroleum-based plastic.
In fact, I have acquired some corn-based drinking straws. They’re all labeled, “compostable,” but while I don’t doubt the fact that they break down, I gotta know how quickly they decompose.
So, first, I wanted to know what they’re really made out of so that I might be able to guess at this. It seems, after some simple research, that this is just a process of fermenting the starches in corn. The sugars in the starch ferment into a substance called, “poly lactic acid,” from which pellets can be made to put into molds for making plastic products.
Interesting. But how long before it breaks down? Well, we’re going to find that out. I am going to put one into my compost bin, one into water, one into white vinegar, and who knows — maybe something off-the-wall. I’ll report back periodically to let you know how it’s going.
I’m betting that the straw in vinegar will decompose the fastest, but who knows? My compost pile is young, and not yet that active, but in an active compost bin, the process may be faster.
Look forward to other products being tested for biodegradability, also!
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Wesley Joseph is the primary editor for EHI. He comes from a strong political science background and is interested in the effect humans' actions have on the environment, how in turn the environment affects humans, and how environmental policy at large and personal actions can both change into positive envirohuman impacts.
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You might be waiting more than a year for them to degrade in home composting systems - but go for it!
Ali,
Thanks for your input! Good to have an expectation going in to the process. At least that is much faster than any petro-based plastic. I’m planning on trying a bamboo plate, bowl, or clamshell product, as well as perhaps having comparison of breakdown time for a traditional paper cup with petroleum-based wax versus a paper cup labeled as, “compostable,” that has plant-based resin keeping the liquid inside.
If anyone has other composting experiments or tests that should be included, let me know!
You’ll be waiting a lot longer than a year. Though no one including the company that makes the resin goes out of their way to clear up the misperception, PLA will only decompose in commercial composting facilities not your bakyard compost pile. The issue is heat. I believe the target heat needed is in the 145 - 155 degree F range. So don’t hold your breath and forget the water treatment. PLA ’s degradability is just like so much of the unscientific ideas and perceptions floating around about what is really good for the environment. Until real science not junk science is used to make decisions on what is or is not best for the environment all that is going to happen is a bunch of greenwashing.
Bryant, thanks for the information!
It’s disappointing when you think you have found a useful, “green,” product, only to find that it doesn’t quite make the grade.
So if people using these straws instead of plastic straws, or maybe a better example is corn-based packaging otherwise, were to actively participate in commercial composting programs (not that they’re at all abundant at this point), do you think that they would be a better alternative to petroleum-based plastic? Of course, waste reduction and recycling are the best options, but I would love to hear Bryant’s and others’ thoughts and opinions.
Also, on the subject of greenwashing, what other examples do you (our readers) see as examples of this happening today? It’s a subject we plan to devote more coverage to and we definitely welcome readers’ input for ideas!
PLA will degrade in a home composter - it just takes a lot lot longer and so it’s not practical for large amounts of waste. Bamboo stuff will be a good experiement! Keep us updated!