What are polymers, and how are they classified?
Polymers are large molecules made up of repeating structural units called monomers, which are covalently bonded. They can be classified based on several criteria:
1. Nature of Monomers: Homopolymers (made from one type of monomer) and copolymers (made from two or more types of monomers).
2. Structure: Linear, branched, or cross-linked polymers.
3. Source: Natural polymers (like proteins and cellulose) and synthetic polymers (like nylon and polyester).
4. Thermal behavior: Thermoplastics (which can be melted and reshaped) and thermosetting polymers (which do not melt on reheating).