porrasreaktiopolymeroinnista

Porrasreaktiopolymerointi, often translated as step-growth polymerization, is a type of polymerization mechanism where monomers containing two or more reactive functional groups react with each other to form larger molecules. This process occurs in discrete steps, with each step involving the reaction between functional groups of existing monomers or oligomers, leading to the formation of dimers, trimers, and eventually long polymer chains. Unlike chain-growth polymerization, where a reactive species propagates by adding monomers to a growing chain end, step-growth polymerization involves the reaction of any two species that have appropriate functional groups, regardless of their size.

The rate of polymerization in step-growth processes is generally slow and can be influenced by the concentration of the reactive functional groups. The molecular weight of the polymer increases gradually throughout the reaction. High molecular weights are typically achieved only when the reaction has proceeded to a very high conversion. Common examples of polymers formed through step-growth polymerization include polyesters, polyamides (like nylon), polyurethanes, and polycarbonates. The choice of monomers with specific functional groups dictates the type of polymer formed and its properties. This polymerization method is crucial in the synthesis of many industrially important materials.