Nonisothermal reaction, thermal stability and dynamic mechanical properties of epoxy system with novel nonlinear multifunctional polyamine hardener

N,N,N′,N′-tetra(3-aminopropyl)-1,6-diaminohexane (TADH), a nonlinear multifunctional polyamine, was prepared and employed as a novel hardener for diglycidyl ether of bisphenol A (DGEBA). Nonisothermal reactions of DGEBA/TADH were systematically investigated with differential scanning calorimetry (DSC). According to the Málek method, the two-parameter Šesták–Berggren model was selected to simulate the reaction rate with a good match achieved, and a correlation of effective activation energies Eα with fractional conversion α was determined with the mode-free isoconversional Vyazovkin method. As α rose, Eα reduced quickly from ∼65 to 57 kJ/mol up to α ≈ 15%, then decreased slowly to ∼50 kJ/mol till α ≈ 75%, and finally dropped to ∼30 kJ/mol at full conversion. In addition, analysis of thermal stability of the cured DGEBA/TADH with thermogravimetric analysis (TGA) revealed that it possessed quite good thermal stability and increased residual char content at 600 °C in nitrogen. Furthermore, dynamic mechanical analysis (DMA) of the DGEBA/TADH network showed its relaxations were characterized by localized motions of hydroxyl ether segments (β relaxation) and cooperative motions of whole network chains (glass relaxation) at different temperature regions.