additionpolymerisation

Addition polymerisation is a type of polymerisation reaction in which monomer molecules add to one another in such a way that the polymer contains all the atoms of the monomer. This process typically occurs through a chain reaction mechanism, involving initiation, propagation, and termination steps. Monomers involved in addition polymerisation are usually unsaturated hydrocarbons, meaning they contain double or triple bonds. Common examples include alkenes such as ethene, which polymerises to form polyethylene, and propene, which forms polypropylene. Other monomers like vinyl chloride and styrene also undergo addition polymerisation to produce polyvinyl chloride (PVC) and polystyrene, respectively. The key characteristic of addition polymerisation is that no small molecules, such as water or ammonia, are eliminated as byproducts during the reaction. This distinguishes it from condensation polymerisation. The molecular weight of the resulting polymer is a multiple of the molecular weight of the monomer. The process can be initiated by free radicals, cations, or anions, depending on the specific monomer and reaction conditions. This method is widely used in the production of many common plastics and synthetic materials.