A DSC KINETIC-STUDY ON THE EFFECT OF FILLER CONCENTRATION ON CROSS-LINKING OF DIGLYCIDYLETHER OF BISPHENOL-A WITH 4,4'-DIAMINODIPHENYL METHANE

The kinetics of formation of epoxy resin composites was studied using an epoxy matrix of diglycidylether of bisphenol-A (DGEBA) and 4,4'-dia minodiphenylmethane (DDM) as curing agent in the presence of quartz fl our as filler. The curing reactions of these systems were kinetically followed by differential scanning calorimetry (d.s.c.) at different sc anning rates. The activation energies of the curing reactions were obt ained using non-isothermal methods: the single scanning rate method of Barrett as well as the multiple scanning rate methods of Kissinger, O sawa and half-width. The crosslinking process is characterized by an a verage activation energy of 54.2-62.7 kJ mol(-1) despite different met hods or filler concentrations being used to obtain it. The reaction ra te for the systems with filler concentrations higher than 10 wt% showe d a considerable decreasing at higher temperatures at conversions high er than 50%. (C) 1997 Elsevier Science Ltd.