kjedevekstprosessen

The chain growth process, known in Norwegian as kjedevekstprosessen, is a fundamental mechanism in the synthesis of polymers. It describes a mode of polymerization where a growing macromolecular chain adds monomer units one at a time while a reactive centre migrates along the chain. Unlike step‑growth polymerization, chain‑growth reactions often require the presence of an initiator to generate the initial active species.

In radical chain‑growth polymerization, for example, an initiator such as a peroxide decomposes to produce free radicals. These radicals react with a monomer to form a new radical centre on the polymer chain. Successive additions of monomers repeat the process until the chain terminates through coupling or disproportionation of two radical chains.

Anionic and cationic polymerizations follow a similar sequence but involve nucleophilic or electrophilic initiators, respectively. In both cases, the active centre remains bound to the chain end, allowing it to continue intercepting additional monomer units. Termination can occur by reaction with a terminating agent or by chain transfer, whereby the active centre is transferred to another molecule.

Industrial applications of kjedevekstprosessen include the production of polyethylene, polypropylene, and polyesters, where control over the chain length and tacticity directly affects material properties. Through careful choice of initiator, temperature, and monomer concentration, manufacturers can tailor polymer characteristics to meet specific performance requirements.