Investigation of the ATRP process through simulations - predicting the limit of control
(English)Manuscript (preprint) (Other academic)
The limit for when a well controlled atom transfer radical polymerization (ATRP) system can be obtained is described based on the results from kinetic simulations where the ATRP equilibrium constant, KATRP, is varied and the rates and degree of control in different ATRP systems are evaluated. The apparent rate constant, kpapp, increases with increasing KATRP, but a maximum is reached where after kpapp decreases as the result of a large degree of initial terminations due to the strong shift of the equilibrium towards the active species. Before the maximum is reached as KATRP is increased, the limit of control is passed, i.e. when KATRP is increased further, apparent first order kinetics and well controlled molecular weights will no longer be obtained. The equilibrium constant at which the limit of control is reached varies linearly with the propagation rate constant. This enables the design of well controlled ATRP systems based on the knowledge of the propagation rate constant and KATRP. The influence of the conversion and chain length dependence of the termination rate constant on the simulation results is also discussed. The kpapp – KATRP trend shown in the simulations is confirmed by comparing with previous experimental results.
atom transfer radical polymerization, catalysis, simulations, kinetics
IdentifiersURN: urn:nbn:se:kth:diva-32103OAI: oai:DiVA.org:kth-32103DiVA: diva2:408878
FunderSwedish Research Council, 621-2005-6190