ABSTRACT
Polymers are molecular materials in which individual molecules or units are chemically bonded in a chain-like structure. The word polymer comes from the Greek roots poly (many) and meros (parts); these parts are known as monomers. Monomers are made up of organic materials in which atoms of carbon are joined in covalent bonds with other atoms of hydrogen, oxygen, nitrogen, silicon, chlorine, ¨ uorine, or sulfur. Natural polymers such as silk, shellac, wood, rubber, and cellulose were available to the ancient man. However, synthetic or semisynthetic polymers, manufactured as industrial products, are recently developed materials. The term “plastics” is a general common name given to most synthetically developed polymers that may contain other constituents to improve performance and/or reduce product cost. Again, “plastic” is derived from the Greek plastikos, which means, •t for molding. It refers to the malleability or plasticity of these polymers during manufacturing that allows them to be cast, pressed, or extruded into a variety of shapes, such as lms, bers, plates, tubes, bottles, boxes, and much more.
