Catalyst effects on the ring-opening polymerization of 1,3-benzoxazine and on the polymer structure

The effect of various catalysts on the ring-opening polymerization of a simple model of 1,3-benzoxazine has been examined in order to compare their catalytic activities and the catalyst effects on the structure of the final polymer. The catalytic activity has been estimated by the conversion of p-cresol-aniline-based benzoxazine and dynamic Differential Scanning Calorimetry analysis of the curing process. The ratio of phenolic to phenoxy structures (which is representative of the rate of phenoxy-phenolic rearrangement), in each case has been determined by 1H NMR analysis of the corresponding cured mixture. Analysis of the 1H NMR spectra of the phenolic final polymer has been also performed, thus establishing the effects of the used catalyst on the structure of the final phenolic polymer.