The Scoop on Bioplastics

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The bioplastics industry has seen tremendous growth in the last few years, especially with the surge in oil prices. From plastic bottles to mobile phones, bioplastics are being used to create products typically made from petroleum-based plastics.

But with this new material comes plenty of questions.

  1. Can you eat the bottle after the liquid inside is gone? (Ok, maybe this isn’t the most serious question. But just in case you were wondering – the answer is “no!”)
  2. What number does it fall under in the plastic recycling chart?
  3. How do these plastics hold up in comparison with their petroleum pals?

Let’s answer these and dive a bit deeper with a quick bio on bioplastics.

How They’re Made

Bioplastics are made of biopolymers, derived from renewable biomass sources such as vegetable oil and corn starch. Made from naturally derived ingredients, bioplastics are essentially biodegradable, a major selling point separating them from petroleum-based plastics.

According to the Freedonia Group, a business researcher, the demand for biodegradable plastic in the U.S. is expected to expand nearly 16 percent annually to 720 million pounds in 2012. However, the industry will admit there is some work to be done. One major area to consider is recycling and composting.

How They’re Handled

Bioplastics often take the place of Polyethylene terephthalate (PET), but they aren’t compatible with this plastic resin when it comes to recycling. Bioplastics are often categorized as #7 plastic, which applies to anything that has a mixture of plastic resins.

It might seem only natural to add these bottles to your PET collection, which is accepted by many curbside programs. However, the recycling industry has had concerns that biopolymers might contaminate the PET stream. Additionally, the main issue comes in the correct identification and sorting of the plastics in the recycling process.

Because bioplastics are made of organic material, composting is another option. However, before you toss these bottles in your compost bin at home, be advised that these bottles may be difficult to compost in that environment. However, some commercial composters will accept them.

Since these plastics are biodegradable, a third option is to put them with the rest of your garbage and let them decompose in a landfill. The issue here is that landfills do not allow adequate light and oxygen for normal decomposition, so it’s unclear how long this will actually take.

Sorting Technology

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Bioplastics are being used to create an array of products, from gift cards to clamshell packaging. Photo:

A number of companies have developed systems to effectively identify and sort bioplastics so they won’t contaminate petroleum-derived plastics during recycling. The systems use near-infrared sorting to identify different polymers, as well as ultraviolet, x-ray, laser, polarized light, fluorescent light, electrostatic, melt point and other sorting techniques.

According to a mixed plastics recycling study conducted by Waste & Resources Action Programme (WRAP), Domestic Mixed Plastics Packaging Waste Options, “NIR (near-infrared) systems can effectively remove PLA bioplastic and carton board from a mixed packaging stream.”

NatureWorks LLC recently released the findings of its bioplastics recycling study, concluding that automated systems currently being used in the recycling industry are capable of sorting natural plastic bottles from petroleum-based plastic bottles with an accuracy of nearly 100 percent.

“Demonstrating that natural plastic bottles can be brought seamlessly into the recycling stream through the use of automated sorting equipment available today is a major finding and another step towards greater sustainability,” said Steve Davies, NatureWorks’ director of communications and public affairs.

The study, conducted over the past two years, surveyed equipment manufacturers that have systems able to sort biopolymers from other plastics, such as PET, HDPE, PVC and PS.

“Accurate sorting is at the heart of making recycling an economically viable business, because the recycling operation must be able to separate materials into pure streams- aluminum separated from steel or PET and HDPE plastics from other polymers,” said Davies.

Lori Brown and Trey Granger contributed to this story.

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