Abstract
The purpose of this work is syntheses of poly (amide-imides) oligomers soluble in epoxy resin, and investigation of curing mechanism of epoxy resin with the oligomers.
Methylester of poly (amide-imides) oligomer (AI-Me) that is soluble in the bisphenol A epoxy resin is synthesized for the use of epoxy resin hardener. The AI-Me has reactive trimellitic acid anhydide end group (Table 1). When the AI-Me and the epoxy resin are heated with 1-cyanoethyl-2-imidazole as catalyst at 200°C for 3 hrs, the cured resin is obtained. In the infrared spectrum of the resin, both the 1650cm-1 band (amide C=O stretching) and the 910cm-1 band for the epoxy groups decreased in intensity and an intense ester band at 1720cm-1 appears (Fig. 4). According to the results of infrared spectroscopy and an investigation on model reaction with epoxy groups and amide groups (Fig. 5), it is found that, in addition the curing between epoxy groups and carboxylic acid groups, another curing takes place through the insertion reaction of epoxy groups to the amide groups.
