additiopolymeerejä

Additiopolymeerejä, often translated as addition polymers, are a major class of polymers formed through an addition polymerization reaction. This process involves the sequential addition of monomer units to a growing polymer chain without the loss of any atoms or byproducts. The monomers typically contain double or triple bonds, which break to form single bonds and allow the monomers to link together.

The most common type of addition polymerization is free-radical polymerization, but other mechanisms such as anionic, cationic, and coordination polymerization also exist. In free-radical polymerization, an initiator molecule generates free radicals, which then attack the double bond of a monomer, creating a new radical on the monomer. This radical propagates by adding more monomers, extending the polymer chain. The process continues until the chain terminates, often through combination or disproportionation of two growing chains.

Examples of common addition polymers include polyethylene, polypropylene, polyvinyl chloride (PVC), and polystyrene. These polymers are widely used in various applications, from packaging and textiles to construction and automotive parts, due to their diverse properties such as flexibility, strength, and chemical resistance, which can be tailored by selecting different monomers and polymerization conditions. The structure of the repeating unit in an addition polymer is identical to that of the monomer, differing only in the absence of the double or triple bond.