Toughening of trifunctional epoxy system. V. Structure-property relationships of neat resin

This work presents an investigation into the structure-property relationships of a cured highly crosslinked epoxy/amine resin system. The mechanical, physical, and thermal properties of the cured and postcured networks were measured and compared to the chemical structures. Crosslink density was shown to be dependent upon secondary amine conversion and it determined the glass transition temperatures, water uptake, density, toughness, and compressive strength. Other properties such as compressive modulus and yield stress were determined by more short-range molecular motions. Curing at a temperature of 150 °C was shown to be the minimum temperature required to `completely' cure the network and achieve optimum mechanical, physical, and thermal properties.