Poly(ethylene glycol) as a 'green solvent' for the RAFT polymerization of methyl methacrylate

We demonstrate the use of a range of poly(ethylene glycol)s (PEGs) to control the polymerization of methyl methacrylate (MMA) using reversible addition-fragmentation chain transfer (RAFT) polymerization. The use of PEG as the solvent (Mn = 4600 g mol−1) resulted in an increase in the rate of the reaction over that of other solvents by a factor of 5 at 60 °C, allowing MMA to be polymerized to high conversions with a DP of 100 much more rapidly than in standard solvents, while maintaining control over the molecular weight with polydispersities as low as 1.05. Interestingly, whilst the same rate increase is seen when polymerizing to a DP of 500, PEG appears to limit the achievable molecular weight to differing degrees depending on its chain length. Advantages of using PEG include its very low toxicity and other environmentally friendly aspects of its nature that allow it to be classed as a 'green' solvent.