INVESTIGATIONS OF 2-ETHYL-2-OXAZOLINE POLYMERIZATIONS IN CHLOROBENZENE

Polymerizations of 2-ethyl-2-oxazoline initiated by alkyl iodides in chlorobenzene have been investigated with regard to their living character, mechanisms, and kinetics. The rate-determining step was found to be an ''initial propagation reaction'' for the case of benzyl iodide as the initiator and initiation in the case of the less reactive 1-iodobutane as initiator. Conversion of active covalent species to ionic species during the course of polymerization was observed in both cases. Absolute number-average molecular weights and molecular weight distributions were analyzed using gel permeation chromatography with universal calibration in a solvent mixture (THF/MeOH). Consistent with the living nature of the systems, the number-average molecular weights of the polymers increased proportionally to monomer conversion. However, the molecular weight distributions of these polymers were found to be broader than a Poisson distribution.