The stigma of bio-degradable plastics

The stigma of bio-degradable plastics

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In the event that our society creates more trash and contamination, scientist get hands on with a  solution to convert the open cycled system us humans have created (cradle-to-grave), into a closed cycled-system designed by nature (cradle-to-cradle). In order to achieve what nature does we need to watch, listen and understand biology in all aspects of its evolution.

History of plastics
Plastics have been under studies since 1862, when Mr. Alexandre Parks demonstrated it in the Great International Exhibition of London calling is Parkesine, a material derived from cellulose (found in nature’s green plants) and the most abundant polymer on earth. As it is insoluble in water, it is more crystalline than starch, although this last one becomes amorphous in water. 1868, John Wesley Hyatt created a derivate from cellulose called celluloid, which when mixed with camphor (obtained from laurel trees) could be molded with heat and pressure. This discovery resulted in the invention of billiard balls and photographic films. In 1899, Arthur Smith obtained a patent of a nearly plastic for chalkboard leading to casein plastic mixing milk protein with formaldehyde, the phenol-formaldehyde used for electrical insulation. In 1907 the reaction was improved by Hendrik Baekeland obtaining a patent with a material called Bakelite, combination of Carbon Acid and phenolic formaldehyde, which resulted into a synthetic resin, the plastics haunting us today, which degrade in 450 years and are not considered today biodegradable of course.

Commonly people realize that if you eat with plastic utensils, it means that you have to discard it once you’re done, which is practical. Consequently, this material ends in a landfill if it is not addressed as some of us try to do today: recycle.

Eco-plastics

Dissolving tray by Plantic

Dissolving tray by Plantic

For this situation to be addressed, scientists are developing new solutions. At Plantic, they have invented a new plastic called Eco-Plastic: a biodegradable material based on a derivative from corn-starch, which is a natural occurring carbohydrate stored in many plants such as the mentioned corn. The magic of this product resides on its deforming capacity when confronted to water, an action provided by starch.

When starch is heated, the crystalline structure is disrupted and upon cooling, typically recrystallizes in a process called retrogradation. This is commonly known as staling, similar to a loaf of bread hardening several days after being baked. To prevent this from occuring in Plantic products, the high amylose starch (…) undergoes a chemical modification process called hydroxypropylation prior to the manufacture of Plantic. This process retards retrogradation and effectively plasticizesthe starch, making it behave like a thermoplastic and proving a shelf life of many years. “

Starch in the end! Mr. Alexander Parks was so near to almost achieving this natural biodegradable plastic! Too bad we ended up with a contaminant!

Now back to this super plastic, what calls the attention here is that similarly to mycelium, this plastic can be thrown away on the dirt and in several days, it will be degraded and digested by other organisms, although fabrication is totally different and much more chemical. Mycelium is not capable of being crystalline.
In the next video, this biodegradability is demonstrated on a bed of worms. Watch the results.

Pine sap plastic

Pine sap close up. Image by Closeuppicsofeveryday.com

Pine sap close up. Image by Closeuppicsofeveryday.com

Another variation of renewable biodegradable plastic is being developed by scientists at the University of South Carolina since 2013. With use of the sap obtained from evergreens as a natural resin, they obtain a rich hydrocarbon which will later on suffer a polymerization process to become biodegradable. The idea that Chuanbing Tang is working on, surpases the use of petroleum based polymers into a more natural and organic based product. He establishes:

With a polymer framework derived from renewable resources, we’re able to make materials that should break down more readily in the environment.”

But as a basic stigma of this type of bio-plastics or bio-polymers: how long will it take to biodegrade? That would be a question answered when this product is finally patented but surely needs to be addressed. When a plastic is stigmatized as “biodegradable” sometimes it is not clearly stated the conditions on which this material has to be, in order to breakdown and degrade. If its environment isn’t according to the lab process, it will take years for degration.
By now, Plantic seems to prove a 10 day degradability and water soluble polymer, although mycelium plastics are on the top of the list at least for other than bottle making; but remember, this doesn’t mean that we will go ahead and throw all bio-degradable plastics outside to see it happening, we have to make it happen. Exactly as people at Plantic say:
“Everything that is compostable is biodegradable, but not everything that is biodegradable is compostable. In other words, composting is a specific set of conditions in which biodegradation occurs.”

References

www.plantic.com.au
www.sciencedaily.com/releases/2013/02/130220170631.htm

 

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Mabelle Plasencia

Founder and Editor at INmatteria©
• Architect | LEED AP BD+C, with an intense passion for materiality, innovation, technology and science. • Arquitecta | LEED AP BD+C apasionada por la materialidad, innovación, tecnología y ciencia.