Polymerisation is a chemical reaction where small molecules called monomers join to form long‑chain molecules known as polymers.
A very large molecule made up of many smaller, repeating units called monomers joined in a chain‑like structure. Examples include plastics, rubber, and proteins.
A small, simple molecule that can join with other similar molecules to form a polymer. For example, glucose is a monomer for starch, and ethene is a monomer for polyethylene.
Monomers add together without losing any atoms. Involves repeated addition of monomers of the same type (usually unsaturated, e.g., ethene).
Example: n C₂H₄ → (C₂H₄)ₙ (polyethene)
Conditions: High temperature, high pressure, and a catalyst.
Monomers join and a small molecule (e.g., water) is released. Involves reaction of two different monomers.
Example: Carboxylic acid + Alkanol → Ester + Water
Examples: Nylon, Terylene (polyester)
Found in living organisms:
Manufactured in industries (plastics):
Soften when heated and harden into new shapes when cooled. Weak intermolecular forces; no cross‑links between chains.
Examples: Polythene, PVC, Polystyrene
Properties: Flexible, can be molded multiple times, easily recyclable.
Set hard and cannot be melted again after formation. Strongly held chains due to cross‑links.
Examples: Melamine, Formica, Bakelite
Properties: Rigid, break under tension, cannot be remolded, not recyclable.
Pipes, plastic bags, bottles, packaging, electrical insulation
Crates, bottles, ropes, artificial leather, water pipes
Insulation, packaging foam, radio cabinets, pot handles
Non-stick frying pans, iron soles
Glass substitute, lenses