chain transfer

(redirected from Chain transfer agent)

chain transfer

[′chān ‚tranz·fər]
(organic chemistry)
The abstraction of an atom from another molecule (initiator, monomer, polymer, or solvent) by the radical end of a growing (addition) polymer, which simultaneously terminates the polymer chain and creates a new radical capable of chain polymerization; also occurs in cationic polymerization.
References in periodicals archive ?
the reversible chain transfer agent is generated in situ in the reaction mixture, thus avoiding the problems of synthesis and storage.
4,4'-azo-bis(4-cianopentanoic) acid, which enables the length of the polymeric chains formed during recording to be controlled, is used as chain transfer agent.
The molecular weight of the model thickeners was controlled by the amount of chain transfer agent (CTA) added during polymerization.
In this method, a sulfide control agent or a multifunctional chain transfer agent is used to control the high-speed radical reaction.
But because the new iodine-carbon bonds have almost exactly the same energy as that of the original perfluoroalkyl reagent, the newly iodocapped polymer chain will serve as a chain transfer agent itself.
The copolymer is prepared by polymerization of 10%-90% by weight of at least one macromonomer (1) having a terminal olefinic unsaturation in the presence of cobalt chain transfer agent, and 90%-10% by weight of a mixture of olefinically unsaturated monomers (2), wherein the percent by weight are based on the total amount of the copolymer and add up to 100% by weight, and wherein the at least one macromonomer (1) is comprised of la) 5%-100% by weight of at least one polymerized acid functional unsaturated monomer, lb) optionally at least one polymerized hydroxy functional unsaturated monomer, 1c) and optionally at least one polymerized olefinically unsaturated monomer different from monomers la) and lb), and wherein the mixture of olefinically unsaturated monomers (2) is comprised of 2a) .
3c and d, respectively), however this can be counteracted, if so desired, by the addition of chain transfer agent.
The model was used to determine the set-point trajectories of the monomers and chain transfer agent that are used as manipulated variables in the control strategy.
A more effective way to control MW and MWD is to use a chain transfer agent (CTA).
The kinetic mechanism used to describe the emulsion copolymerization of XSBR latexes is based on the classical free radical polymerization model, comprising the usual reaction steps: initiation, propagation, chain transfer to monomer, chain transfer to a chain transfer agent, chain transfer to dead polymer chains, and termination by disproportionation and combination (22).
6] developed an iterative dynamic programming to find optimal monomer and chain transfer agent (CTA) feed profiles to produce polymer with specific copolymer composition and MWD.