Studies on Curing Reaction Kinetics of Epoxy Resin Cured by Silicon-containing Aromatic Diamines

Two diamino silicon-containing compounds 3,3'-(1,3-dimethyl-1, 3-divinyl-1,3-disiloxanediyl) bis (benzenarnine) (S1) and 4, 4'-(1, 3-dimethyl-1, 3-divinyl-1, 3-disiloxanediyl)-bis (benzenamine) (S2) were synthesized and used as the novel curing agents of DGEBA epoxy resin with an epoxy value of 0. 51 (E51). The curing kinetics were studied by non-isothermal differential scanning calorimetry (DSC) technology. Curing processes of the two systems were determined according to the change of characteristic temperature at different heating rates as 100 degrees C/1 h + 160 degrees C/2h + 190 degrees C/3h for E51/S1 and 110 degrees C/1 h + 170 degrees C/2h + 190 degrees C/3h for E51/S2. The curing parameters including activation energy AE, Arrhenius frequency factor A and reaction order n were analyzed by Kissinger equation, Crane equation and Arrhenius equation. AE is 50.65 kJ/mol, A is 1.83 x 10(5), n is 0.87 for E51/S1; AE is 51.39 kJ/mol, A is 1.44 x 10(5), n is 0.87 for E51/52. According to the value of AE and A, the reaction activity between E51 and S2 is higher than that of E51 and Si, in other words, it is easier for ring open reaction when -NH2 in the para position of benzene ring. The reaction orders of E-51/S1 and E-51/S2 are the same and both less than 1, implying that the curing reaction is complicated. And nth-order curing models of the curing systems were obtained based on the curing kinetics parameters.