Synthesis and Characterization of Novel Poly(aryl ether pyridyltriazine)s

Abstract

Poly(aryl ether pyridyltriazine)s were synthesized by two approaches. In the first approach novel pyridyltriazine-containing monomers, 3-(2′-pyridyl)-5,6-bis(4′-fluorophenyl)-1,2,4-triazine and 3-(2′-pyridyl)-5,6-bis(4′-hydroxyphenyl)-1,2,4-triazine, were prepared and reacted with various bisphenols and activated aromatic difluorides, respectively, via a nucleophilic aromatic substitution reaction. A conventional potassium carbonate/dipolar aprotic solvent reaction procedure was employed with the exception of higher temperatures (195–235 °C) and a higher boiling solvent (i.e., N-methylcaprolactam). High molecular weight polymers were achieved in reactions with 3-(2′-pyridyl)-5,6-bis(4′-hydroxyphenyl)-1,2,4-triazine. However, for polymers prepared with 3-(2′-pyridyl)-5,6-bis(4′-fluorophenyl)-1,2,4-triazine, evidence of cross-linking accompanying the linear polymerization was detected. The second synthetic approach involved preparing poly(aryl ether benzil)s and then reacting them with (2-pyridyl)hydrazidine to form poly(aryl ether pyridyltriazine)s. The polymer modification reaction was quantitative and proceeded with no detectable backbone cleavage. From a synthetic viewpoint, the latter approach proved to be more advantageous, since difficulties associated with either the stability or reactivity of heterocyclic (e.g., triazine) monomers could be bypassed. All of the poly (aryl ether pyridyltriazine)s were amorphous and exhibited glass transition temperatures in the range 202–277 °C, significantly higher than the glass transition temperatures of the parent benzil polymers (167–242 °C). The thermooxidative stability of the polymers prepared was excellent; 5% weight loss in air occurred in the range 420–447 °C. Some of the polymers were both solution and melt processable, and all formed tough clear creasable films. © 1994, American Chemical Society. All rights reserved.