Investigation of the Living Cationic Ring-Opening Polymerization of 2-Methyl-,2-Ethyl-,2-Nonyl-,and 2-Phenyl-2-oxazoline in a Single-Mode Microwave Reactor

摘要

The living cationic ring-opening polymerizations of 2-methyl-,2-ethyl-,2-nonyl-,and 2-phenyl-2-oxazoline were performed in acetonitrile at high temperatures of up to 200 deg C in a single-mode microwave reactor.Upon enhancing the reaction rates by factors of up to 400 in the range from 80 to 200 deg C,the first-order kinetics of the monomer consumption and the livingness of the polymerization were maintained.As a consequence of the fast,direct,and noncontact heating by the microwave irradiation,the polymerizations could be carried out in highly concentrated solutions or even from bulk conditions,yielding well-defined polymers(PDI < 1.20).Under the conditions applied in this study,a maximum number of 300 monomers(100 in the case of 2-methyl-and 2-nonyl-2-oxazoline)could be incorporated into the polymer chains under the premise that the average molecular weight distributions remained narrow(PDI < 1.20).