Rheological and thermal behaviour of DGEBA/EA and DGEHQ/EA epoxy systems crosslinked with TETA

Isothermal variation of the viscosity has been investigated in the temperat ure range 20-60 degreesC for diglycidyl ether of bisphenol A/epoxy aniline/ triethylenetetrlunine (DGEBA/EA/TETA) and diglycidyl ether of hydroquinone/ epoxy aniline triethylenetetramine (DGEHQ/EA/TETA) systems. The variation o f the viscosity versus time and temperature has been determined using a 'Rh eotest 2.1' viscometer equipped with cone and plate geometry (36 mm diamete r and 0.3 degrees angle) at a shear rate of 1 s(-1). The cure kinetics were studied using the DSC technique. The thermal behaviour of cured products w as investigated by thermogravimetric analysis using a MOM Budapest derivato graph. The activation energies for the curing reaction calculated from the gel time have values between 18.78 kJ mol(-1) for the DGEBA/EA/TETA and 60. 93 kJ mol(-1) for the DGEHQ/EA/TETA system. The cured products present good thermal stability, the activation energies of decomposition have values of 96.46 kJ mol(-1) for the DGEBA/EA/TETA and 93.70 kJ mol(-1) for the DGEHQ/ EA/TETA system. (C) 2001 Elsevier Science Ltd. All rights reserved.