Investigation of curing kinetics of diglycidyl ether of bisphenol A and zinc (II) complexes using dynamic DSC technique

Abstract

Cure kinetics of the reaction of diglycidyl ether of bisphenol A with inorganic complexes based on zinc (II) chelate with diethylene triamine (Dien) as ligand were studied using non-isothermal differential scanning calorimetry (DSC). The complex curing agents were synthesized and characterized by elemental analysis, FT-IR, and ICP- Plasma techniques. Thermal dissociation behaviour of curing agents was also studied using thermogravimetric (TG) analysis in isolated form. The parameters of non-isothermal curing kinetics, activation energy (Ea), pre-exponential factor (A) and rate constant (K) were obtained according to Kissinger, Ozawa, and iso-conversion equations. The activation energy values for DGEBA/Zn(Dien)2Br2 and DGEBA/Zn(Dien)2(NO3)2 systems obtained by Kissinger method were 106.50 and 86.95, by Ozawa method were 108.63 and 91.12 kJ/mol and by iso-conversion equation were 107.67 and 92.66 kJ/mol, respectively. The values for pre-exponential factor (A) obtained for DGEBA/Zn(Dien)2Br2 and DGEBA/Zn(Dien)2(NO3)2 systems were 4.80 × 1011 and 4.44 × 107 s−1 with rate constants (K) of 0.90 and 0.12 s−1, respectively. The DSC thermograms of DGEBA with bromide complex showed two exothermic peaks, while DGEBA curing with nitrate complex displayed only one isolated peak.