Monday, March 7, 2011

Choices of degradable Plastic Films !!

Choice of degradable Plastic Film
When selecting a degradable plastic from various types of technologies, you have to pick the one that fits your needs. 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 trash can liners as there is no sunlight in the landfill’s quickly buried layers of trash.

Photodegradable Plastic Film
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 has to be stored away from any sun or UV rays. It cannot be recycled. The degradation process may not continue once the degraded plastics are tilled into the soil. Thus away from the light photodegradable plastic product is actually not biodegradable.

Thermal Based Technology for degradable Film
Thermal based plastic has an additive put into it as it is being extruded making it to degrade when exposed to high temperatures. This is the key to how it works. Without high temperatures, it might take longer for it to degrade. With variable temperatures in landfills, this needs to be considered. It could degrade when stored in hot garages or warehouses. It cannot be recycled.

Oxo Biodegradable plastic film
Oxo Biodegradable plastic is polyolefin plastic to which has been added very small (catalytic) amounts of metal salts. These catalyze the natural degradation process to speed it up so that the plastic will degrade when subject to environmental conditions to produce water, carbon dioxide and biomass. The process is shortened from hundreds of years to years and/or months for degradation and thereafter biodegradation depends on the micro-organisms in the environment.

Bio-based or Starch based Biodegradable Plastic
Bio-based or starch based plastic is made from corn, soy, and potatoes. This form of biodegradable film meets the ASTM standard for compost-ability as it degrades at least 60% within 180 days or less. The heat, moisture, and aeration in a compost pile are vital to this type of biodegradable film working well. Bio-based plastics have moisture problems. If you toss a half-empty cup of coffee into a can liner made with some starch-based products, you might have the bottom of the bag giving away! Landfills do not aerate the trash coming in and hence would take longer time degrading under conditions of limited access to oxygen, water, and during the winter or in colder climates. This technology is currently very costly. It cannot be recycled.

Anerobic Bio-degradable Film

Maverick Green is an additive-based biodegradable film that is formulated to degrade when buried or put into a landfill. 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 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. It can be recycled and reused in post consumer plastic.   

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