Plastics are typically organic polymers of high molecular mass commonly derived from petrochemicals.
Plastics are usually classified by its structure, chemical process used in its synthesis, physical properties. However the most important classification is by the permanence or impermanence of their form namely Thermoplastics and Thermosets or thermosetting plastics.
Thermoplastics are the plastics that, when heated, do not undergo chemical change in their composition and so can be molded again and again. Examples include: polyethylene (PE), polypropylene (PP), polystyrene (PS) and polyvinyl chloride (PVC).Thermosets, or thermosetting polymers, can melt and take shape only once: after they have solidified, they stay solid. In the thermosetting process, a chemical reaction occurs that is irreversible. The vulcanization of rubber is an example of a thermosetting process: before heating with sulfur, the polyisoprene is a tacky, slightly runny material; after vulcanization, the product is rigid and non-tacky.
Plastic recycling is the process of recovering scrap or waste plastic and reprocessing the material into useful products. Since the vast majority of plastic is non-biodegradable, recycling is a part of global efforts to reduce plastic in the waste stream.
Single-use plastics, or disposable plastics, are used only once before they are thrown away and littered. These items are things like plastic carry bags, plastic flags, plastic sheets used for food wrapping, spreading on dining table etc, plastic plates, plastic coated tea cups and plastic tumblers, water pouches and packets, plastic straws irrespective of thickness.
Plastic chemicals (EX: phthalates, plasticizer, stearic acid etc.) have a tendency to get bio accumulated. They are hormone mimicking chemicals which may cause reduction in the fertility rate. Several chemicals such as styrene, plasticizers, anti-oxidants, acetaldehyde tend to migrate from the plastic containers into the food being carried by them.
The clogging of water ways prevents the flow of water into water bodies and stagnates resulting in breeding of mosquitoes and causing diseases of malaria, dengue etc. It prevents percolation of rain water into soil affecting ground water recharge. Also the single use plastics results in soil erosion, open burning leads to emission of toxic air pollutants etc
The theme of 2018 World Environment Day was “Beat Plastic Pollution” and India was the host country. The theme urges governments, industry, communities, and individuals to come together and explore sustainable alternatives and urgently reduce the production and excessive use of single-use plastic polluting our oceans, damaging marine life and threatening human health.