Polymerization of alkenes is the process in which many small alkene molecules, called monomers, join together to form a very large molecule called a polymer. The important feature of alkenes is their carbon–carbon double bond, which can break to allow the monomers to link together.
There are two main types of polymerization for alkenes:
- Addition (chain-growth) polymerization – This is the most common type for simple alkenes. The double bond in each alkene opens up, allowing monomers to add one after another, forming a long chain without producing any by-products.
- Condensation (step-growth) polymerization – Less common for simple alkenes, this involves monomers combining and releasing a small molecule like water or hydrogen chloride.
Examples of polymers made from alkenes:
- Ethene forms polyethylene, used in plastic bags and bottles.
- Propene forms polypropylene, used in containers and ropes.
- Vinyl chloride forms PVC, used in pipes and flooring.
- Styrene forms polystyrene, used in packaging and disposable cups.
Importance:
Polymerization of alkenes is the foundation for making many plastics and synthetic materials that are used in everyday life.