Synthetic polymers and their applications

Introduction

              Use of man-made synthetic polymeric meterials plays a huge effect on our everyday life. A large number of industries (e.g. packaging, textile, automobile, paper etc ) are based on synthetic polymers (poly = many ; mer = Parts ) such as polyethylene (PE), poly (vinyl chloride) (PVC), polyesters, nylon etc. and natural polymers such as rubber, cellulose, etc These natural polymers have been used for a long time, for example natural rubber was discovered in 1492 by columbus when he was in south america.

              Synthetic polymers can be classified according to their response to heat. A thermoplastic polymer is one that can be softened by heating and then formed into desired shapes by applying pressure (moulding). In contrast, thermosetting polymers are permanently hard at elevated temperatures and pressures. They cannot be softened and remoulded. Polymers can be divided mainly into four types depending on their properties - plastics (e.g. PVC) , fibres (e.g. polyamides), elastomers (e.g rubber) and adhesives (e.g. resins). One of the most interesting uses of polymers  (e.g. biomedical polymers) has beer as replacements for diseased, worn out or missing parts of the human body such as leg , arm, lung, heart, liver, kidney, arteries, teeth , knee joints and hip joints. Synthetic polymers could pose a serious threat to environment unless we make them biodegradable. 

             All polymers are macromolecules with the same repeating unit but all macromolecules are not polymers. For example, proteins and nucleic acids (DNA and RNA) are macromolecules but they do not have the same repeating unit. Natural polymers and macromolecules such as polysaccharides (e.g. Cellulose, starch, etc) and nucleic acids (responsible for heredity) based on sugars and phosphates are discussed in session.

            When naming homopolymers (i.e polymers with one monomer unit), the name of the monomer is written after the prefix poly, e.g polyethylene. If the name of the monomer is not a one word the name of the monomer is written within brackets, e.g. poly (vinyl chloride).