Koordinasjonspolymerisering

Koordinasjonspolymerisering is a type of chain-growth polymerization mechanism that relies on a coordination complex, typically a transition metal compound, to catalyze the process. In this mechanism, the monomer coordinates to the active site of the catalyst before insertion into the growing polymer chain. This coordination step is crucial and dictates the stereochemistry of the resulting polymer, leading to highly controlled structures.

Key to coordination polymerization is the ability of the catalyst to activate the monomer through coordination, forming a metal-monomer complex. This complex then undergoes a migratory insertion reaction, where the monomer adds to the metal-carbon bond of the growing chain. The catalyst then re-establishes its coordination site, ready to accept the next monomer. This cycle repeats, leading to chain growth.

This method is particularly important for the synthesis of stereoregular polymers, such as isotactic polypropylene and cis-1,4-polyisoprene. The nature of the catalyst and its ligands plays a significant role in controlling the stereoregularity, molecular weight, and tacticity of the polymer. Ziegler-Natta catalysts and metallocene catalysts are prominent examples of systems used in coordination polymerization, enabling the production of a wide range of polyolefins with tailored properties.