Atom-transfer radical polymerization
(ATRP) has been studied up to 2500 bar via online
VIS/NIR-spectroscopy to monitor the evolution of both CuII
concentration and monomer conversion. ATRP-equilibrium constants
have been determined under polymerization conditions (KATRP) and in
monomer-free model systems (Kmodel) for several combinations of
ligands and initiators. Two branched and two linear ligands have
been used. Initiators have been chosen to mimic the structure of a
bromine-capped chain-end which occurs during ATRP of styrene,
methyl methacrylate (MMA) or n-butyl acrylate (n-BA) with chain
length unity.
Applying pressure significantly enhances the Kmodel which is
adequately represented by the reaction volume, ΔVR, model. The
obtained values range from ‒16 cm^3
