Biodegradable plastic bags

Abstract

Consulta en la Biblioteca ETSI Industriales (8752)

[EN] More than fifty years ago, natural materials started to be substituted by synthetic polymers, due to its better properties, use flexibility, manufacturability and processability, in addition to the huge cost effectiveness and longevity. Nowadays, in many areas, natural materials use has disappeared. The synthetic polymers had more stability and durability than the natural materials, and these properties have been improved along the time. Good news from the uses point of view, but not from the environmental one. Plastic is an inert material, what means that have strong resistance to biodegradation. Plastics are resistant to microbial attack, which cannot degraded them, and cannot design new enzymes to get it. Plastics do not break down in the environment easily; need many years to get an important degradation, what is not useful for the earth, due to the fact that each year human being throw tones of plastics, endangering the environment. One plastic bag needs four hundred years to be degraded. The largest compound in plastic wastes is low density polyethylene, at about twenty three percent, followed by polypropylene, at about eighteen percent. The next most found compound is high density polyethylene, almost seventeen percent. Polystyrene, polyvinyl chloride and polyethylene terephthalate, are found at about ten percent. These materials are used to manufacture plastic bags, which everyone can get in the markets. These plastic products have produced important damage to the environment, and the future does not look better, because every year plastic bags production increases. At the beginning, the attitude of the plastic industry was that plastic waste was a very small proportion of the human wastes. But since 1960 to 2000 the world production of plastic increased twenty-five fold. In landfills the problem is the huge volume needed for the plastic bags. Same landfills are almost full, have reached capacity, and there is an urgent need to find solution to this problem, new places where situate new landfills, but these are difficult to find.