Traditional shopping bag is usually made from polyethylene, which consists of long chains of ethylene monomers. Ethylene is derived from natural gas and petroleum. The polyethylene used in most plastic shopping bags is either low-density or more often is high-density. Plastic shopping bags are commonly manufactured by blown film extrusion. Each year millions of discarded plastic shopping bag ends up as litter in the environment when improperly disposed of. Due to their durability, plastic shopping bags can take up to 1000 years to decompose. Because this many country start to reduce and restrict use plastic shopping bags. And many kinds reusable shopping bag gradually became the theme. People begin have realize about the environmental. You can find many kinds reusable shopping bag begins more common in our life.