Polyadditiopolymerointi

Polyadditiopolymerointi, also known as addition polymerization, is a fundamental process in polymer chemistry. It involves the stepwise joining of monomers, typically containing double or triple bonds, to form long polymer chains. Unlike condensation polymerization, addition polymerization does not release any small byproduct molecules, such as water or HCl. The process typically proceeds through a chain reaction mechanism, which can be initiated by various species, including free radicals, cations, or anions.

The initiation step involves the formation of a reactive species from the initiator molecule. This reactive species then attacks a monomer, opening its double or triple bond and creating a new reactive center on the monomer. This process is then propagated as the reactive center adds more monomer units, extending the polymer chain. The chain growth continues until termination occurs, which can happen through several mechanisms, such as combination or disproportionation of two growing chains, or by reaction with an inhibitor.

Common monomers that undergo addition polymerization include alkenes like ethylene and propylene, styrene, vinyl chloride, and acrylates. The resulting polymers, such as polyethylene, polypropylene, polystyrene, and polyvinyl chloride, are ubiquitous in modern life, finding applications in packaging, textiles, construction, and electronics. The control over molecular weight and polymer architecture can be achieved by manipulating reaction conditions, initiator concentration, and temperature.