A new biodegradable plastic with no microplastics!
It's not clear that this will make major in roads against non-biodegradable plastics without a carbon tax or some other form of help. It will likely stay a niche product if it can be scaled up for widespread commercial use.
A compatible second polymer was found by trial and error. The researchers found a safe crosslinking agent made from positively charged polyethylene-imine guanidinium ions. When the cellulose and guanidinium ions were mixed in room temperature water, the negatively and positively charged molecules attracted each other and formed the cross-linked network that makes the plastic strong. In the presence of salt water, the salt bridges holding the polymers together broke as would be expected.
EurekAlert! reports about the new plastic in an article, The perfect plastic? Plant-based, fully saltwater degradable, zero microplastics. Researchers led by Takuzo Aida at the RIKEN Center for Emergent Matter Science (CEMS) in Japan published the discovery of their new plastic in the Journal of the American Chemical Society. The plastic is made from two polymers, charged polyethylene‑imine guanidinium ions and carboxymethyl cellulose or plant cellulose. Cellulose the world’s most abundant organic compound. Nature makes about a trillion tons of it per year in all kinds of plants. The new plastic is strong, flexible, and it rapidly decomposes in natural environments. No other "biodegradable" plastic so far has this property.
A compatible second polymer was found by trial and error. The researchers found a safe crosslinking agent made from positively charged polyethylene-imine guanidinium ions. When the cellulose and guanidinium ions were mixed in room temperature water, the negatively and positively charged molecules attracted each other and formed the cross-linked network that makes the plastic strong. In the presence of salt water, the salt bridges holding the polymers together broke as would be expected.
To make the plastic more flexible and thus useful in real world applications, the researchers eventually found that choline chloride worked. Choline chloride (CC) is an FDA-approved food additive. By adding varying amounts of CC to the plastic, the researchers fine-tuned exactly how flexible the plastic would be. Depending on the amount of CC in the mix, the plastic can range from being hard and glass-like to being so elastic that it can be stretched up to 130% of its original length. It can be made into a strong thin film with a thickness of 0.07 mm. This video shows a bag with little tomaters (I think) in it made from the biodegradable plastic. The bag is disintegrating and dissolving in salt water. There's lots of salt water on Earth.
Dancing tomatoes in
a little CMCSP bag
The new carboxymethyl cellulose plastic, called CMCSP, is as strong as current oil-based plastics. Its mechanical properties can be adjusted as needed without spoiling its intrinsic transparency, processability, seawater dissociability, or close-loop recyclability. The plastic's ingredients are common and inexpensive FDA-approved biodegradable compounds.
This is a very nifty little chemistry trick! Very cool. I approve.
Yay, go chemistry!
By Germaine: Opposed to microplastics in our bodies, brains, blood, fetuses, eyeballs, ear lobes, etc.
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