Bioplastics: From Corn to Corner Shop

With plastics causing more and more issues globally, new replacement materials are in greater demand than ever before. Typical plastics serve near infinite purposes and can take virtually any form, but are made from nasty petrochemicals that are toxic and pollute the environment. One clever solution to the plastic problem is using bioplastics instead. Bioplastics, which are derived from plant sources, promise a world of similar plastic items, but with the capacity to decompose instead of be recycled. They’re made from plants instead of petroleum!

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In order to better understand the benefits and drawbacks of bioplastics, it is important to distinguish between a few definitions. Here are the vital ones:

Biodegradable: technically, all materials are biodegradable. Everything breaks down naturally into smaller and smaller bits, like rocks into sand. Common plastics supposedly take hundreds to thousands of years to biodegrade, that is, to return completely to constituent elements like carbon and water, but we have no evidence to support these guesses. Items that are considered biodegradable can also leave behind toxic residues.

Compostable: capable of breaking down completely and into non-toxic compounds. In the case of compostable bioplastics, special facilities are needed to maintain the right conditions for items to fully breakdown.

Bioplastic: any plastic made from plant-based sources. They can be completely or only partially biomass sourced. Corn and sugarcane provide the raw materials (starch and cellulose) to craft bioplastics.

Typical plastics are synthesized from oil. Plastics not only consume millions of barrels of oil annually but also persist in the environment for hundreds of years. The current system is harmful for numerous reasons, but is deeply established and will be hard to replace.

We’re great at producing plastics, but awful at recycling them. For more info on this, read this blog.

It’s been known for decades (since Wallace Carothers discovered PLA in the 1920’s) that plastics can be made from natural sources, but nobody bothered to develop industrial production capacity for more expensive raw materials (like biomass, corn, and sugarcane) when oil was--and is--so cheap.

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Bioplastics are becoming more common and important today because their composition allows them to rot away. They also offer the same characteristics (rigid, light, capable of storing soda) as petrochemical plastics. The most common type of plant based plastic is Polylactic Acid (PLA). PLA is derived from plant starch and cellulose. It is completely compostable, and after ten to fourteen days at around 140ºF, only water, CO2, and heat will remain.

If a bioplastic is entirely compostable, it must be brought to a specialized site that maintains the proper conditions for complete decomposition. Bioplastics’ capacity to break down fairly quickly without any toxic residue make them ideal for replacing petroplastics.

It cannot all be so simple and obvious, unfortunately.

A worrisome attribute of bioplastics is that they have to be effectively collected, which has proven to be a problem with recyclables. If they aren’t collected and decomposed properly, they’ll sit around for decades. Additionally, if bioplastics are mixed into PET or other recyclable plastic bales, the whole bale can be unfit for reclamation and end up in a landfill. If bioplastics are only partially compostable, the compostable part cannot be separated from the rest (which is regular plastic), hence the whole item will be trashed.

Though bioplastics are a better alternative to standard plastics, they are far from perfect. The truth is, it’s unlikely that they’ll find their way to the proper composting facilities 100% of the time, just as recyclables don’t get recycled 100% of the time.

So what can you do?

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Identify your plastics! If you see this symbol , know that the item is compostable. Any other symbol or RIC number means the plastic is petroleum based and potentially recyclable.

Check online to see if your area has an industrial composting facility. If so, figure out where to deposit your compostables so they are collected properly. Never place PLA or other compostable bioplastics in the recycling!  

Know that you cannot simply toss a bioplastic and expect it to decompose. It needs specific conditions.

Otherwise, try to avoid plastics altogether. It’s hard, but there are ways to do it. Buy stuff packaged in glass or free of packaging completely.

The future of plastics is likely a combination of using more compostable bioplastics and reducing the overall inputs of all types of plastics into consumer markets. By reducing the amount produced, and properly managing the discarded plastics, be it recycling or composting, the tide of plastic waste will begin to slowly turn.

 

Clara von Dohlen