Traditional plastic is made from petroleum products. The production of petroleum-based plastics involves all kinds of chemicals, some of which have raised health concerns among consumers. The other problem is that these type of plastics do not biodegrade and they are made with a non-renewable resource: petroleum. There are just lots of environmental and health concerns associated with conventional plastics.
Thankfully, plastics technology has come a long way. There are now biocompostable plastics made from renewable, biodegradable corn starch. In fact, you’ve probably already seen them. Have you ever used a plastic cup and noticed the text made from corn? Then, you’ve used corn start biocompostables!
How Are Corn Starch Biocompostables Made?
As the name implies, corn starch biocompostables are made from corn starch. The starch is converted into a polymer, the main ingredient in materials that have a plastic-like feel. The plastics can be clear or opaque, soft or hard. A kind of acid called polylactic acid (PLA) is made from the corn starch. This is why corn starch biocompostables are sometimes called PLA plastics.
PLA plastics are molded the same way conventional plastic is. They can be molded, extruded, or shaped by heating and cooling (thermal shaping).
Biocompostable Means More than Biodegradable
Biocompostable plastics are called so because they are a step beyond just biodegradable. For a plastic to be considered biocompostable, it must meet certain criteria. For instance, it must decompose at the same rate as paper, and it must break down into harmless material such as water, carbon dioxide, or biomass (organic matter).
Biocompostable plastic must not produce any toxic substances as it decomposes. It must also break down to the point that it cannot be discerned or filtered out of the surrounding compost. PLA plastics cannot be recycled. They must be composted.
The Benefits of Corn Starch Biocompostables
- No toxic chemicals associated with conventional plastic (such as polyvinyl chloride or dioxin)
- Can be disposed of in your home compost pile
- Eco-friendly (made from a renewable resource and less wasteful)
- Especially well-suited for cold applications, such as in the freezer (this is good news, since chemicals from conventional plastic tend to leach into food when frozen)
- Corn allergies are not an issue since the allergen, profilin, is destroyed in the manufacturing process.
The Disadvantages of Corn Starch Biocompostables
- May not be as heat resistant
- Not microwave safe
- Can’t be thrown in the garbage or recycled; must be composted at home or in a commercial facility
- Thicker, harder items such as cutlery can takes up to 180 days to break down
Common Types of Biocompostable Items Made from Corn Starch
There are all sorts of items that can be made with PLA plastic. Here are some of the most common biocompostable plastic items:
- Cups (hot and cold)
- Water bottles
- Food storage containers (including “clamshell” containers used by take-out restaurants)