The polymerization mechanism and kinetics of DGEBA with BF3-EDA

The diglycidyl ether of bisphenol-A (DGEBA) and boron trifluoride ethylene diamine complex (BF3-EDA) were used to identify the species responsible for initiating epoxy polymerization. Experiments using the dynamic technique of differential scanning calorimeter (DSC) showed the results that the BF3-EDA complex breaks down rapidly into active species at 100 degrees C and above. The active species, HBF4, complexes with the epoxy groups, producing an activated oligomer that reacts with epoxy in a polymerization reaction. It has been shown that the complex formation reaction can be resolved from the epoxy/epoxy polymerization reaction. The activation energies for the complex formation reaction is 74 kJ/mol and for polymerization reaction is 175 kJ/mol. The amine alone (EDA) cures DGEBA with a maximum peak of 100 degrees C in 14 min while its complex with BF3 cures DGEBA with a maximum peak of 200 degrees C in 20 min under the same conditions. (C) 1998 Elsevier Science Ltd. All rights reserved.