Plastic bags are used in grocery, clothing stores and specialty stores often. In order to help the environment, many of people choose to use reusable bags or recycling old plastic bags when people go shopping. And stores try to lessen their impact on the earth by providing biodegradable plastic bags to their customers. Biodegradable bags are bags that are able to disintigrate into their base components, regardless of what those components are, under specified conditions of light, moisture, and oxygen. They are classified by the polymers they are made of.

Biodegradable Polymers
Biodegradable polymers primarily biodegrade using microorganisms to break down enzymes after the plastic reacts with oxygen. Biodegradable polymers decompose into water, methane, carbon dioxide or inorganic compounds.

Oxo-biodegradable Polymers
Oxo-biodegradable polymer plastic is made by adding a pro-degrading agent to plastic while it is in the extrusion process. This additive triggers an accelerated oxidative degrading process when the bag is exposed to UV rays or mechanical stress. Once disposed, Oxo-biodegradable polymers will degrade in about 12 months. Oxo-biodegradable plastic has no difference in texture, quality or strength to non-biodegradable plastic.

Photodegradable Polymers
Photodegradable polymers is made by adding UV-sensitive additives to plastic. Once disposed of, the polymers are broken down photochemically into smaller pieces. The small pieces are further broken down with microbial degradation.

Compostable Polymers
Compostable polymers work with the composting process to be broken down into total mineralization. Compostable polymers break down quickly using bacteria, algae or fungi into water, methane, carbon dioxide or inorganic biomass.

Water-soluable Polymers
Water-soluable polymers are designed to break down when in put in contact with water. The polymers only break down at a certain temperature and are fully biodegrade using microorganisms.

Starch-based Polymers
Starch-based polymers are made primarily of renewable sources. Thermoplastic starch-based polymers contain 90 percent of corn, wheat or potato. Star-polyester blends mix renewable sources with hydrocarbons. Starch-based plastic bags break down in 180 days or less, depending on environmental conditions.

AS we all known, there is only one earth. What we have done to the environment will pay back to our sons finally. In the sake of our descendant, it is necessary to protect the environment, lessen the harms to the environment and beautify the environment.