SYNTHESIS AND CHARACTERIZATION OF NOVEL POLY(ARYL ETHER PYRIDYLTRIAZINE)S

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 degrees 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 degrees C, significantly higher than the glass transition temperatures of the parent benzil polymers (167-242 degrees C). The thermooxidative stability of the polymers prepared was excellent; 5% weight loss in air occurred in the range 420-447 degrees C. Some of the polymers were both solution and melt processable, and all formed tough clear creasable films.