Askelpolymeroituminen

Askelpolymeroituminen, also known as step-growth polymerization, is a polymerization technique where monomers, typically with two or more functional groups, react with each other to form dimers, trimers, and longer oligomers. These oligomers then react further to form high molecular weight polymers. This process occurs in a stepwise manner, meaning that at any point during the reaction, the mixture contains a wide range of molecular weights, from monomers to the final polymer.

Key characteristics of askelpolymeroituminen include the requirement for monomers to have at least two reactive functional groups, such as hydroxyl, carboxyl, or amine groups. The reaction typically proceeds by the elimination of a small molecule, like water or methanol, for each bond formed between monomers. This type of polymerization is often reversible under certain conditions. Common examples of polymers formed by askelpolymeroituminen include polyesters, polyamides (like nylon), polyurethanes, and polycarbonates. The molecular weight distribution in askelpolymeroituminen is often described by Flory-Schulz distribution. The rate of polymerization is generally slow and can be influenced by catalyst concentration and temperature. The degree of polymerization is directly related to the extent of reaction.