Choosing the Right Biodegradable Plastic
When choosing the biodegradable plastic that you are going to use, you have to ask several questions in order to get the correct type of biodegradable plastic to suit your requirements:
- First of all and most importantly, how are you going to use the plastic?
- What is its function? Is it a mailer, a can liner, box liner, a bag for a compost pile?
- What are the conditions it will be exposed to and how will it be ultimately disposed?
- How is the plastic going to be stored and for how long?
Photodegradable Plastic Film
When selecting a biodegradable plastic from various types of technologies, you have to pick the one that fits your needs without any unwanted surprises. For example, if you wanted a plastic to degrade in the sun as you grow crops in the Sunbelt and want the plastic to degrade by the end of the growing cycle, then a photodegradable plastic would be your best choice. It would not be the best choice for a trash can liner as there is no sunlight in the landfill’s quickly buried layers of trash. The photodegradable plastic needs constant exposure to the sun in order to degrade. The downside to this technology is that while degrading, it begins to break apart and in some cases little pieces of plastic blow away. One has to closely monitor the degradation process and not let it go beyond the breaking apart level. It does have to be stored away from any sun or UV rays. It cannot be recycled. Also one has to question whether the degradation process continues once the degraded plastics are tilled into the soil and thus away from the light that would normally continue the process determining whether or not a photodegradable plastic product is actually a true biodegradable plastic.
Biobased or Starch based Biodegradable Plastic
Another biodegradable plastic is biobased or starch based. It is made from corn, soy, and potatoes. This form of biodegradable film meets the ASTM standard for compostability as it degrades at least 60% within 180 days or less. Anyone who uses compost piles or sends their compost to municipal compost should definitely use this technology. The heat, moisture, and aeration one gets in a compost pile are vital to this type of biodegradable film working well. One does have to be careful of some biobased plastics that have moisture problems. If you were to toss a half-empty cup of coffee into a can liner made with some starch-based products, you might have any angry janitor when the bottom gives out of the bag as he picks it up to throw it away. Landfills do not aerate the trash coming in; so biobased would have a harder time degrading under conditions of limited access to oxygen, water, and during the winter or in colder climates. This technology is currently very costly and it cannot be recycled.
Thermal Based Technology for Biodegradable Film
A third type of biodegradable plastic is thermal based. This is a plastic that has had an additive put into it as it is being extruded making it degrade when exposed to high temperatures. This is the key to how it works. Without high temperatures, it might take longer for it degrade. Thus with variable temperatures in landfills, one has to take this into consideration. This plastic meets ASTM 6400 standards for compostability and is excellent for compost bags or bags used for compost going to a local compost pile. However, usually comes with expiration dates and it could degrade when stored in hot garages or warehouses. It cannot be recycled.
Maverick Green - Anerobic and Aerobic Biodegradable Film
Maverick Green is an additive-based biodegradable film that is formulated to degrade when buried or put into a landfill. This is Maverick Green Film. It interacts with the biota in the landfill, which in turn enables it to degrade. These microorganisms metabolize the molecular structure of the plastic, breaking it down into humus and then into either carbon dioxide and water or methane and water. This process is done both aerobically (with oxygen) and anaerobically (without oxygen). This ability sets it apart from other biodegradable plastics that require oxygen. In the layers of garbage, oxygen would be in limited supply. This product does not produce or leave any toxic residue harmful to living organisms in land or water. Basically an additive is put into the plastic while it is being made, thus making it biodegradable. It looks and performs like a normal plastic with no moisture, heat, or water issues. In comparison to the other technologies, it usually is the most user friendly and least expensive. Any polyethylene or polypropylene product can be made with this product. This technology is being used in bags by our troops in Iraq. However, it does not meet the ASTM 6400 standard for compostability, as it does not degrade 60% within 180 days or less. Instead, under those conditions, it would take approximately 9 to 18 months. It can be recycled and reused in post consumer plastic. The advanages of Maverick Green are:
Longer shelf life than most biodegradable films
Longer working life
Can be custom manufactured in a variety of styles and resin types
More versatile and suitable for a broader range of applications