A polymer is a macromolecule composed of one or more molecules or molecular groups (structural units or monomers) bonded together by covalent bonds to form multiple repeating monomer units.
These molecules or groups of molecules are called "monomers," and a polymer may have branches or just be a straight line of molecules, with each one connected in the same way. Polymers have a range of different chemical and physical properties, but they generally have one thing in common: they are fairly stable molecules.
Polymers can be divided into carbon chain polymers, heterochain polymers and elemental organic polymers according to the elemental structure of the main chain of the molecule. The main chain of the macromolecule of carbon chain polymers is completely composed of carbon atoms, such as polyethylene, polystyrene, etc. In addition to carbon atoms, the main chain of the macromolecule of heterochain polymers also contains heteroatoms such as oxygen, nitrogen, and sulfur, such as polyether, polyester, polyamide, etc.
In addition, the characteristics of polymer materials include a wide variety, low density, high specific strength, good electrical insulation, good corrosion resistance, easy processing, etc. They can meet the requirements of a variety of special uses and are widely used in plastics, fibers, rubber, coatings, adhesives and other fields.
