THE EFFECT OF COPPER OXIDES ON THE CURING OF BROMINATED EPOXY-RESINS

The kinetics of the curing of the brominated epoxy resin/dicyandiamide (DICY) system in the presence of copper oxides was investigated by is othermal differential scanning calorimetry (DSC). In essence, the heat of curing of brominated epoxy resins increases with increasing temper ature as a result of the decrease in unreacted residual DICY at high t emperature. The addition of small amounts of CuO and Cu2O to the resin s results in an increase in unreacted DICY left in the cured resins. P referential adsorption of DICY on copper oxides is responsible for thi s difference. However, the amounts of unreacted DICY can be decreased by adding 2-methylimidazole (2-MI) to the resins. From large differenc es in enthalpy values and reaction orders but relatively unchanged T(g ) values among various specimens obtained during curing of brominated epoxy/DICY/2-MI, it can be established that the system during curing c ould involve complex competing reaction mechanisms which cannot be des cribed with a simple mathematical expression.