Tailoring the viscoelasticity of epoxy thermosets

This research work is aimed to understand the effect of epoxy resin chemistry on the viscoelasticity of the cured epoxy thermosets. In this article, two model systems are selected based on epoxy-amine reactants. In the model Systems I, the functionality of the epoxy is varied. In model System II, the pendant (side) chain length in the amine is varied. It is found that by varying the initial properties (e.g., functionality, pendant chain length, mixing ratio (r), aromaticity, etc.) the network properties (crosslink density and flexibility) of the cured (or hardened) epoxy changed. The changes (or shift) in the viscoelastic properties (or viscoelasticity) of the cured epoxy is mainly due the changes in the network properties. Further, to study the time and temperature effects the viscoelastic master curves for the two model systems are generated using Time-Temperature-Superposition (TTS) principle. The shift in the viscoelastic master curves is modeled with a simple Kohlrausch-Williams-Watts (KWW) fit function. (c) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013