As is know to us, plastic is very difficult to biodegrade. Usually it takes at least 50years to decomposition. You can find many plastic products such as belt hangers, plastic bags in our daily life.

Avoiding plastic biodegradable problem, everyone had better reduce to use belt hangers, plastic bags. Also if necessary, plastic products should be recycled. Biodegradable plastics break down (degrade) upon exposure to sunlight (e.g., ultra-violet radiation), water or dampness, bacteria, enzymes, wind abrasion, and in some instances, rodent, pest, or insect attack are also included as forms of biodegradation or environmental degradation. Some modes of degradation require that the plastic be exposed at the surface, whereas other modes will only be effective if certain conditions exist in landfill or composting systems. Starch powder has been mixed with plastic as a filler to allow it to degrade more easily, but it still does not lead to complete breakdown of the plastic. Some researchers have actually genetically engineered bacteria that synthesize a completely biodegradable plastic, but this material, such as Biopol, is expensive at present. The German chemical company BASF makes Ecoflex, a fully biodegradable polyester for food packaging applications. Companies have made biodegradable additives to enhance the biodegradation of plastics.

Most plastics are produced from petrochemicals. Motivated by the finiteness of petrochemical reserves and possibility of global warming, bio-plastics are being developed. Bio-plastics are made substantially from renewable plant materials such as cellulose and starch. Nowadays, many belt hangers makers buy such bio-plastic for production. In comparison to the global consumption of all flexible packaging, estimated at 12.3 million tons per year, estimates put global production capacity at 327,000 tons per year for related bio-derived materials.

Some plastics are partially crystalline and partially amorphous in molecular structure, giving them both a melting point, the temperature at which the attractive intermolecular forces are overcome and one or more glass transitions, temperatures above which the extent of localized molecular flexibility is substantially increased. The so-called semi-crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride), polyamides (nylons), polyesters and some polyurethanes.