(i) A polymer is composed of many simple molecules that are repeating structural units called monomers. A single polymer molecule may consist of hundreds to a million monomers and may have a linear, branched, or network structure.
The four basic polymer structures are linear, branched, crosslinked, and networked.
(ii) Synthesis:
- Natural polymers: Polymers which are found in nature i.e., in plants and animals are called natural polymers. For example: proteins, cellulose, starch, some resins, rubber etc.
- Semi-synthetic polymers: Polymers which are mostly derived from naturally occurring polymers by chemical modifications are called semi-synthetic polymers. For example, in cellulose on acetylation with acetic anhydride presence of concentrated sulphuric acid yields cellulose diacetate which is used for making theards of acetate rayon and other substances like films, glasses etc.
- Synthetic polymers: A variety of synthetic polymers as plastics (polythene, polypropene), synthetic fibres (nylon, polyester) and synthetic rubbers (neoprene, polystyrene) are examples of man made polymers extensively used in daily life as well as in industry.
(iii) A polymer is composed of many simple molecules that are repeating structural units called monomers. A single polymer molecule may consist of hundreds to a million monomers and may have a linear, branched, or network structure.
