Microwave-assisted synthesis and properties of a series of poly(2-alkyl-2-oxazoline)s

Microwave-assisted organic synthesis is a quickly expanding field of research. The fast non-contact (super)heating of the reaction mixtures has already resulted in many examples of increased reaction rates and improved yields. However, the number of investigations focusing on microwave-assisted polymerizations, and especially living/controlled polymerizations, is still limited. Following our recent success in accelerating the cationic ring-opening polymerization of 2-oxazolines, we report here our studies on the cationic polymerization of a series of linear 2-alkyl-2-oxazolines under microwave irradiation. The effect of chain length on the polymerization kinetics was investigated. Moreover, the microwave polymerization of 2-ethyl-2-oxazoline was further investigated by 1H-NMR spectroscopy to determine the active species during the polymerization. Besides the microwave polymerization of the linear 2-alkyl-2-oxazoline monomers, the thermal and surface properties of the resulting polymers were investigated by DSC and contact-angle measurements to study the effect of side-chain length on the polymer properties.