In the present work, the flexibility of an epoxy adhesive containing diglycidylether of bisphenol-A (DGEBA) and diethylenetriamine (DETA) as curing agent was changed by the addition of a second component containing mercaptan groups (CAPCURE). The addition of asbestos as a filler in the adhesive containing CAPCURE was also evaluated. Epoxy-amine and epoxy-mercaptan reactions were studied in NIR and MIR spectral regions. The filler addition did not cause influence on the cure reactions and spectrometric changes of cure reactions could be better observed by FT-NIR than FT-MIR analysis. The cure reaction time was monitored by DSC experiments and it was observed that the introduction of CAPCURE accelerated the cure reaction. The activation energies (Ea) of curing reactions were obtained using Barrett and Borchardt-Daniels methods. The adhesives containing CAPCURE showed Ea around 30 kJ.mol-1, while DGEBA/DETA adhesive presented Ea of 46 kJ.mol-1 calculated by Barrett method.
Adhesive; epoxy; mecaptan; MIR; NIR; DSC
