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In terms of mechanism, an ideal RAFT polymerization has several features. The pre-equilibrium and re-initiation steps are completed very early in the polymerization meaning that the major product of the reaction (the RAFT polymer chains, RAFT-P n), all start growing at approximately the same time. The forward and reverse reactions of the main ...
In polymer chemistry, polymerization (American English), or polymerisation (British English), is a process of reacting monomer molecules together in a chemical reaction to form polymer chains or three-dimensional networks.
Therefore, to terminate the polymerization, a quenching agent must be added, such as a strong acid to protonate the polymer, or a nucleophile to add an end cap the polymer. If the π-complex is too weakly bound, termination of polymer chains can occur before a quenching agent is added, causing lower molecular weight polymers to form.
Radicals can be formed by a number of different mechanisms, usually involving separate initiator molecules. Following its generation, the initiating radical adds (nonradical) monomer units, thereby growing the polymer chain. Radical polymerization is a key synthesis route for obtaining a wide variety of different polymers and materials ...
Living polymerization: A chain polymerization from which chain transfer and chain termination are absent.. Note: In many cases, the rate of chain initiation is fast compared with the rate of chain propagation, so that the number of kinetic-chain carriers is essentially constant throughout the polymerization.
Mechanisms and thermodynamics of ring-opening polymerization were established in the 1950s. [15] [16] The first high-molecular weight polymers (M n up to 10 5) with a repeating unit were prepared by ROP as early as in 1976. [17] [18]
The halogen remaining at the end of the polymer chain after polymerization allows for facile post-polymerization chain-end modification into different reactive functional groups. The use of multi-functional initiators facilitates the synthesis of lower-arm star polymers and telechelic polymers. External visible light stimulation ATRP has a high ...
This work provided the foundations for the synthesis of polymers with improved control over molecular weight, molecular weight distribution, and the architecture. [7] The use of alkali metals to initiate polymerization of 1,3-dienes led to the discovery by Stavely and co-workers at Firestone Tire and Rubber company of cis-1,4-polyisoprene. [8]