Oxygen Tolerance Study of
Photoinduced Electron Transfer–Reversible
Addition–Fragmentation Chain Transfer (PET-RAFT) Polymerization
Mediated by Ru(bpy)<sub>3</sub>Cl<sub>2</sub>
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Abstract
This
study reports a highly efficient photoredox catalyst, Ru(bpy)<sub>3</sub>Cl<sub>2</sub>, capable of controlling the polymerization
of methacrylates, acrylates, and acrylamides in the presence of thiocarbonylthio
compounds via a photoinduced electron transfer–reversible addition–fragmentation
chain (PET-RAFT) process. This polymerization technique was performed
in a closed vessel in the presence or absence of air. Online Fourier
transform near-infrared spectroscopy (FTNIR) was employed to monitor
the monomer conversions of methyl methacrylate, methyl acrylate, and <i><i><i>N,N</i></i></i>′-dimethylacrylamide
in the presence or absence of air. Interestingly, after an induction
period, the polymerization proceeded in the presence of air to yield
well-defined polymers (PDI < 1.20). The polymers were characterized
by <sup>1</sup>H NMR, UV–vis spectroscopy, and gel permeation
chromatography. Excellent end-group retention was also demonstrated
by NMR, UV–vis, and successive chain extensions of the resulting
homopolymers to yield diblock and multiblock copolymers (decablock
copolymers)