Curing kinetics of diglycidyl ether of Bisphenol-A epoxy system using a tertiary amine, through the study of its rheometric characteristics

The curing reaction of the epoxy system “diglycidyl ether of bisphenol-A” (DGEBA) and the tertiary amine “2-[(2-dimethyl-amino)-ethoxy] ethanol” (DMAE), with different DMAE concentrations was studied by means of rheometric analysis using the Rubber Process Analyzer (RPA). A novel simple technique was introduced in order to allow the use of the RPA instrument in measuring the curing studies of quasi liquid reactants. It was found that the crosslinking degree; as measured by: a)- the maximum torque in the RPA analysis as well as by b)- the estimated molecular weight between crosslinks (Mc); increased with the DMAE concentration. Also, it was found that the curing reaction rate, increased with the DMAE concentration; greatly decreasing the time to gel point as well as the time to maximum torque. The degree of crosslinking, as taken from the crosslink density or by the molecular weight between crosslinks, increases roughly seven times as the tertiary amine (DMAE) concentration increases from 3 to 10 wt%. The activation energy of the crosslinking reaction was determined by plotting as an Arrhenius type equation, the log(Geltime) -vs- the inverse temperature, and it was found to be around 42.9 kJ/mol.