What’s the deal with Bioplastics?

Lately I have been hearing a lot about biodegradable plastics or bioplastics. So, what are bioplastics and what are their pros and cons?

Well, bioplastics are often used in packaging materials and dinnerware as an eco-friendly alternative to petroleum-based plastics. They are made from renewable plant sources, such as corn starch, pea starch, sugar cane, or vegetable oil. Some of these bioplastics are made to decompose in a a commercial composting facility and some simply reap the benefits of being made from a renewable material, that is, they do not use petroleum in their manufacturing process.

Plant-based biodegradable drink cup

So, what are the main benefits of biodegradable plastics made from plant based materials? This new eco-friendly plastic has several things going for it:

(1) It is made from renewable sources and does not have to use the estimated 200,000 barrels of oil a day in the US that is used to make conventional plastic packaging. This also means that it will not leach chemicals into our compost piles or landfills.

(2) Under certain conditions its principle component, polylactic acid (PLA), can break down (decompose) into harmless natural compounds. Since approximately 1/4 of our landfills are taken up by plastics, this could decrease the amount of plastic-based garbage filling up our landfills. In addition, producing PLA uses 65 percent less energy than producing conventional plastics.

(3) With the rising oil prices, using corn to make plastic may be a cheaper alternative.

Now this sounds like it is too good to be true… a perfect plastic that is made from renewable resources, that can decompose, and that doesn’t leach chemicals. Well, there are some drawbacks to these biodegradable plastics that haven’t received the same amount of press.

When I first heard of these biodegradable corn-based plastics I thought “Awesome, I’m going to throw this biodegradable plastic fork into my vermi-compost bin and see what happens.” But before I did this, I did a little research and found out that these biodegradable plastics are not so biodegradable after all. According to the Smithsonian online magazine article “Corn Plastic to the Rescue”, PLA is said to decompose in a “controlled composting environment” in fewer than 90 days. So what does this mean? It means that PLA will only decompose in a large facility where the compost is digested by microbes in a container that reaches 140 degrees for ten consecutive days. In other words, bioplastics will not decompose in your vermi-compost or outdoor compost bins, or in a landfill. They could end up sticking around as long as conventional plastics… which can be as long as 100 to 1,000 years.

Also, make sure you don’t mix bioplastics into your regular plastic recycling bin. Drink bottles and milk jugs are typically made of polyethylene terephthalate (PET); however some companies are beginning to make them out of PLA plastic. When drink bottles are recycled they are sent through plastic processors that break down the plastic into pellets or flakes, which are then made into new products. However, PET and PLA plastics mix about as well as oil and water… which makes PLA a contaminant in PET plastic recycling. This means that plastic processing facilities have to pay to sort it out and have to pay a second time to dispose of it.

President of the Grassroots Recycling Network and a proponent of the Zero Waste movement, Eric Lombardi explains that while there are problems with PLA and biodegradable plastic we shouldn’t “kill the good in pursuit of the perfect.” Using PLA-based plastics instead of petroleum-based ones utilizes renewable materials, saves oil and generates far less air pollution. But where do we take them to be recycled? Will they have a better chance of ending up in a landfill because they can’t be recycled with conventional plastics?

In the end, is using biodegradable plastics the way to go? What do you think?




Brie Bennett
Green Guerrilla Sustainability




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