Learning about novel amine-adduct curing agents for epoxy resins: Butyl-glycidylether-modified poly(propyleneimine) dendrimers

Novel butyl-glycidylether-modified poly(propyleneimine) dendrimers (PPIs) are prepared by reacting butyl glycidylether with PPI, which turn out to be able to cure bisphenol-A epoxy resin to an acceptable reaction extent. The nonisothermal reactions, dynamic mechanical properties and thermal stabilities of their cured epoxy resin are comparatively investigated with DSC, DMA and TGA, respectively. The model-fitting kinetic study demonstrates that Šesták–Berggren model can generally well simulate the reaction rates, and the isoconversional kinetic analysis with the Vyazovkin method indicates the curing agents, particularly their setric hindrance and the number of the –OH groups attached, greatly affect reaction kinetic schemes. Increasing the number of the BGE substituents attached to PPIs decreases the reactivity, glass- and beta-relaxation temperatures and thermal stability of the resulting epoxy systems, yet the intensity and width of the glass relaxation increase. This work offers a unique way of preparing modified-aliphatic-polyamine curing agents, and provides an opportunity to better learn about the amine-adduct curing agents which are widely used in room-temperature-cure epoxy coatings and adhesives from these good model compounds.