CURING BEHAVIOR AND PROPERTIES OF EPOXY-RESINS CURED WITH THE DIAMINEHAVING THE QUINOXALINE OR TRIAZINE STRUCTURE

2,3-Bis(4-aminophenyl)quinoxaline (1a), 2,3-bis(4-aminophenyl)-6-methy lquinoxaline (1b), and ,6-bis(4-aminophenyl)-3-(2-pyridyl)-1,2,4-triaz ine (2) were studied as curing agents of epoxy resins. The exotherms o n differential scanning calorimetry thermograms of the mixtures of dig lycidyl ether of bisphenol A (DGEBA) with 1a, 1b, and 2 were observed at higher temperatures than that of the mixture of DGEBA with a commer cially used diamine, for example, 4,4'-diaminodiphenylsulfone (DDS). H owever, the epoxy resin cured with 1a (EP-1a) showed higher tensile st rength to stainless steel at 20 degrees C than that cured with DDS, an d the high tensile strength of EP-1a was maintained even at 180 degree s C. The epoxy resin cured with 1b or 2 also possessed higher tensile strength at 20 degrees C than that cured with DDS, but the high tensil e strength lowered somewhat at 120 degrees C. Using diamines 1a, 1b, a nd 2 as a curing agent improved heat distortion temperatures of the cu red epoxy resins. (C) 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69 : 1737-1741, 1998.