Stepcondensation

Stepcondensation refers to a type of chemical reaction where two or more molecules combine to form a larger molecule, typically with the loss of a small molecule like water or methanol. This process is characterized by a series of sequential steps, rather than a single concerted reaction. In each step, a reactive intermediate is formed, which then reacts with another molecule to extend the polymer chain. This contrasts with some other polymerization mechanisms that might involve simultaneous addition of monomers.

The term "stepcondensation" is often used interchangeably with "step-growth polymerization" when referring to the formation of polymers. In this context, monomers with functional groups react with each other to form dimer, trimer, and eventually longer polymer chains. The small molecule is eliminated at each condensation step. For example, the formation of polyesters involves the reaction between dicarboxylic acids and diols, with the elimination of water. Similarly, polyamides are formed from dicarboxylic acids and diamines, also eliminating water. The rate of polymerization in stepcondensation is generally dependent on the concentration of functional groups. As the reaction progresses, the concentration of these functional groups decreases, leading to a slower rate of chain growth. This type of polymerization can be initiated by various catalysts, depending on the specific monomers and functional groups involved.