Cross-linking of bisepoxide with divalent metal salts of p-aminobenzoic acid and anhydride

Cross-linking of bisepoxide with divalent metal salts of p-aminobenzoic acid and dicarboxylic acid anhydride was investigated. As the bisepoxide, bisphenol A diglycidyl ether was used and hexahydrophthalic anhydride was the anhydride used. As the divalent metal, Mg and Ca were selected. In the cross-linking reactions, the metal salts showed catalytic activities. In this case, the salt containing Mg exhibited higher catalytic activities than that containing Ca. The cross-linking reaction was supposed to proceed via a complex mechanism. The cured resins obtained contained amide and ester groups and ionic linkages. As for the physical properties of the novel metal-containing cured resins, tensile and flexural strengths decreased with an increase in the metal content. However, Rockwell hardness was not affected by the metal content. There was a good correlation between heat distortion temperature and Tg determined by dynamic mechanical properties. Against boiling water, the resins exhibited low weight gain, low change in dimension, and no change in external appearance. In addition, thermal decomposition was accelerated by the incorporated metal.