Cyclohexanone/P-aminophenol/formaldehyde resins as hardener of epoxy resins

Cyclohexanone, p-aminophenol and formaldehyde in varying molar ratios were condensed under base catalysis. The resins thus obtained were characterized by spectroscopic methods and used as hardener for epoxy resins. The curing behaviour of diglycidyl ether of bisphenol A (DGEBA), diglycidyl ether of hydroquinone (DGEHQ) and diglycidyl of aniline (DGAN) was investigated using cyclohexanone/p-aminophenol/formaldehyde resin as curing agent. The curing and temperature behaviours of the cured products were studied by DSC and TGA techniques. The activation energies for the curing reaction calculated by the Ozawa and Kissinger methods are observed to be in the range of 69.0-184.0 kJ/mol, depending on epoxy systems. The activation energy for the decomposition reaction of the cured products have values situated in the range of 48.0-74.0 kJ/mol.