The age of plastics: Demand for materials like plastics is continually growing and will not be abated. The magnitude of the plastics industry, however, is itself a cause for concern.
Today, 200 billion pounds (100 million tons) of plastics are produced worldwide every year.
The total volume of plastics produced worldwide has surpassed that of steel and continues to increase. Without a doubt, we have entered the Age of Plastics.
Some common plastic items include: sunglasses, tooth brushes, super glue, paint brushes, tennis shoes, Frisbees, 2-liter bottles, Honda CRX's, Astroturf, photographs, street signs, pens, automobile paint, video tapes, rubber bands, balloons, bicycle tires, umbrellas, guitar strings, carpeting, shower doors, hearing aids, Scotch Tape, fishing lines, trash bags, and toilet seats. Plastic can be found in everything from clothing to machinery.
Traditional plastics fail on all three of these points.
- Renewability: how quickly are the ingredients that go into making the plastic created in the environment?
- Degradability: how quickly can the plastic be re-integrated into the environment after it is no longer being used?
- Production: how much pollution or waste is created during the process of actually making the plastic?
In order to help clear up some of the confusion regarding what is and what isn't Green, we will define some terms which are used in describing some of the products on the market today.
Bagasse: The biomass remaining after sugarcane stalks are crushed and the juice extracted which is then ground up and made into paper pulp for dinnerware and various containers.
Biodegradable: Any product that is capable of decaying over time through the action of living organisms or bacteria.
Compostable: Any product that is capable of decaying over time through the action of living organisms and a combination of heat and humidity. Ideal composting conditions are 150? F and 90% humidity.
PLA: Acronym for Poly Lactic Acid which is a biodegradable thermoplastic resin derived from natural renewable resources like corn or sugar cane.
Recyclable: Any product capable of being used again after being treated or processed to make it suitable for reuse.
Renewable Resource: A natural resource that can be replenished at a rate comparable to its rate of consumption. In other words, we use less than what grows or occurs naturally. Sugarcane takes one year to maturity versus a tree which takes thirty years!
The usual range for biodegradability lies between 60-90% decomposition within two to three months in standard composting environments.
The polymer molecules of conventional plastics are too large and their underlying chemical bonds too tight to be broken apart by microbes. Biodegradable plastics that are easily decomposed by microorganisms persist for much shorter time in nature, and they may provide viable alternatives.
The chemical bonds of biodegradable compounds are easily destroyed by a variety of bacteria over a small period of time that facilitates their decomposition.
Compared to starch polymers the environmental benefits of poly (lactic acid), currently accounting for 10-15% of production, and of biodegradable polymers made from nonrenewable resources; accounting for approximately 10% of production, seem to be smaller, but still greater than conventional polymers. For microbial polyesters, which currently make up a very small part of total green plastics production, the environmental advantage seems to be small (or perhaps nonexistent), but the fermentation technologies for producing them are among the most recently developed, and both the production method and the scale of production can influence evaluations of the overall environmental balance.