Ahelpolümeeriseerumise

Ahelpolümeeriseerumine is a type of chain-growth polymerization where monomers add sequentially to an active growing chain. This process typically involves initiation, propagation, and termination steps. In the initiation step, an active center is formed, often by the addition of an initiator molecule to a monomer. This active center, which can be a radical, anion, or cation, then attacks another monomer molecule, extending the chain. The propagation step is the repetitive addition of monomers to the growing active chain end. This process continues rapidly, leading to the formation of long polymer chains. Finally, the termination step ends the growth of a polymer chain. This can occur through various mechanisms, such as radical combination or disproportionation, or by reaction with impurities. The molecular weight of the polymer is influenced by the relative rates of propagation and termination. Ahelpolümeeriseerumine is a fundamental polymerization mechanism responsible for the production of many common plastics and synthetic materials. Examples include the polymerization of ethylene to polyethylene, propylene to polypropylene, and vinyl chloride to polyvinyl chloride. The specific type of active center dictates the subclass of ahelpolümeeriseerumine, such as free-radical polymerization, anionic polymerization, or cationic polymerization, each with its own unique characteristics and applications. Understanding this mechanism is crucial for controlling polymer properties like molecular weight, tacticity, and branching.