Propagation and termination kinetics of PEGylated methacrylate radical polymerizations
- Propagation and chain-length averaged termination rate coefficients, k(p) and <k(t)>, for radical polymerizations of methacrylates carrying poly(ethylene glycol) (PEG) units are reported. kp derived from pulsed laser initiated polymerizations in bulk, in organic solvents, and in ionic liquids follows the methacrylate-type family behavior. Contrary, diffusion controlled k(t) values obtained from chemically initiated polymerizations with in-line FT- NIR monitoring of monomer conversion are strongly affected by the PEG units in the ester group. Compared to alkyl methacrylates <k(t)> is unexpectedly high. Moreover, <k(t)> of poly(ethylene glycol) ethyl ether methacrylate shows a significant reduction in k(t) already at 15% conversion, whereas dodecyl methacrylate <k(t)> is constant up to at least 70% conversion.
