Biodegradable Plastic

After last week’s article on the Garbage Patch, it seemed necessary to look into biodegradable plastic options. Not only is plastic non-biodegradable, it also continues the US dependence on oil. Plastic consumes around 331 million barrels of oil a year, accounting for about 4.6% of the US petroleum consumption [Source: Energy Information Administration]. In order to slowly ween ourselves off of oil, more biodegradable options made from different materials have been created. Currently there are some biodegradable plastics made from: corn, feather and hemp.

Corn
Plastic made from corn has been in production since 1989, but hasn’t had industry success until the past four years. NatureWorks, one of the largest lactic acid plants in the world, is also one of the first companies producing the resin polyactic acid (PLA) from corn. This resin is formed into pellets, much like petroleum-based plastic, to create either injection molded objects (forks, packaging) or films (saran wrap, trash bags). While corn-based plastics are biodegradable, they can only biodegrade quickly in controlled compositing facilities. These buildings allow compost to reach 140 degrees fahrenheit for ten straight days to spur on the process of biodegradation. There are currently only 113 identified facilities in the US that can compost PLA plastics. For areas that do not have mandatory composting, like San Francisco, or composting facilities, it may very well be impossible to compost these plastics as most consumers cannot reproduce the environment in these facilities. PLA left in a normal backyard compost may not biodegrade at all [Source: Smithsonian Magazine]. Other issues with PLA plastic include recycling problems. Consumers often toss in PLA with PET and when recycled together can cause contamination and render the final product useless. PLA also faces the same problem as biodiesel derived from corn. Recent estimates state that there isn’t enough land to grow enough corn for PLA to match current plastic consumption [Source: Treehugger].

Feathers
The creation of plastic made from feathers is relatively recent. Walter Schmidt and Justin Barone from the Agricultural Research Service (ARS) have patented a way to convert chicken feathers into plastic. US poultry farms discard a total of 4 billion tons of chicken feathers a year. These feathers are a major source of agricultural waste. Creating this plastic requires half the amount of heat and pressure necessary for traditional plastic. The process breaks down the sulfur-sulfur bonds in the keratin, and when the plastic solidifies so does the keratin [Source: Pieces]. This makes the plastic very durable and adaptable. And because keratin biodegrades, the plastic does as well. In fact, scientists can determine how quickly the plastic degrades, ranging from several months for flower pots to several years for automotive parts. Unfortunately, the product is still in development though flower pots made from this material are slated for release in 2011 [Source: VOA News].

Hemp
Companies have known that hemp could be made into plastic for awhile. In fact, Henry Ford demonstrated the durability of plastic made from hemp when he created the “hemp car” in 1941. Sixty-some odd years later, a British company called Hemp Plastics, has rediscovered this amazing plant. The company has created a 100% hemp feedstock plastic and produces cd/dvd cases, spice grinder, kitchen scale and even musical instruments. [Source:Treehugger]. European automotive companies have also jumped on the hemp bandwagon and have replaced fiberglass with biodegradable plastic/hemp composites [Source: Sustainable Life Media]. One of the many reasons that hemp is an attractive replacement for oil is its high yield. Hemp grown for seed and biomass a yield of 3.5 tons/acre. Though this is lower than the yield for corn, hemp farms do not have to produce any foodstuffs. This allows for the entire yield being used for plastic, oil, clothes, etc.

The technology to create biodegradable plastics has been around for decades, but traditional plastic continues to litter the oceans and overflow in landfills. While two microbes have been isolated as agents that degrade plastic (Sphingomonas bacteria and Pseudomonas), there hasn’t been any research into what the plastic actually degrades to and proper disposal methods [Source: The Record]. Biodegradable plastic is not a panacea but if used in conjunction with better recycling habits it could slow down landfill growth.

Treehugger
Jasmine Greene

131 comments

Carolt M.
Past Member 2 years ago

Thank you so much for your all great explanation, I liked reading this.
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Jack R.
Jack Roberts5 years ago

While their are multiple easy solutions to this mess PLA is not one of them corn based plastics are full of GMO and are a problem. We need to focus on plastic technologies that don't support modifying our food supply.

This Technology seems to make Biodegradable Plastic without that modification.

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Biosphere P.
Biosphere P.5 years ago

Lots of technologies in the BioPlastic realm, www.biosphereplastic.com is one of them. PLA and the rest of the gang of bioresins won't be able to even convert PS and PET resin types, so I am not sure why there is a plastic bottle on the top of this post :p

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Adam K.
Douglas K6 years ago

This is great news! A lot of firms are making bioplastics. I want all plastic firms ordered by the government to only make biodegradable plastic. Else the gyres, the ocean garbage patches, the water consists of 10 parts plastic and one part plankton, according to the movie documentary Addicted To Plastic.

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chiari l.
Chiari L7 years ago

better than the alternative.

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April I D.
April I D7 years ago

I hihgly recommend the story of Stuff for any people who want to know more. The plastics industry has misled us into believing that because some of their products can be recycled, they are not harmful. They are, and there are better ways to store things, buy food at the grocery store, etc. Ways that do not endanger the viability of the oceans and the future of this planet.

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Beng Kiat Low
low beng kiat7 years ago

thanks.

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Kelly c.
Kelly c7 years ago

Very good article on sustainability of plastics! But do take note that recycleable plastics do not necessarily mean they are safe.

Bio-plastics may contain chemical additives used in modern but destructive industrial agriculture system (eg. genetically modified corn). You can find more details in this PDF document: http://www.healthybuilding.net/bioplastics/SustBioplasticGuide.pdf

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valerie g.
valerie g.7 years ago

this is a great example of human intelligence providing a viable solution! there will be better ones yet down the road, but this is absolutely a great start! much of recycling is energy inefficient, but recycle we must. we're doing the best we can to figure out better and better ways. but to only consume and not look at the mess we're leaving is no longer tenable.

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James C.
James C.7 years ago

The trouble with PLA apart from 5 times the cost is the resources used to make it, 14,200 kg of crops needed to make 1,000kg of PLA, then due to waste only 600kg of workable product. Not the answer.

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