Initiating efficiency of poly(ethylene glycol)-based initiators for transition metal mediated living radical polymerisation

The kinetics of the copper mediated living radical polymerisation of methyl methacrylate initiated by [poly(ethylene glycol) methyl ether]-based initiators (MeOPEG) of various molecular weights was followed by 1H NMR. The initiator efficiency of the macroinitiators was investigated. It was found that temperature and solvent have little effect on the reactivity of the macroinitiator, whilst chain length affects greatly the MeOPEG initiating efficiency. Steric hindrance is thought to be a main drawback, as difficult access of the monomer to the MeOPEG active chain-end and coordination of the copper catalyst to the MeOPEG chains can prevent the monomer to react with the macroinitiator.