Effect of molecular packing and hydrogen bonding on the properties of epoxy-amido amine systems

Molecular packing and hydrogen bonding have been hypothesized to affect a number of properties of epoxy-amido amine thermosets. However, these correlations have not been verified extensively and a molecular level rationale for the hypotheses is lacking. In the present work, molecular dynamics simulation is used to explore correlations relating void fractions, volume fractions and hydrogen bonding to the properties of epoxy-amido amine thermosets of varying alkyl chain compositions. Properties considered here include density, thermal expansion coefficients, glass transition temperature, Young's modulus, solubility, diffusivity and permeability of water. Simulation results indicate that void fraction has no direct bearing on these properties. The hydrogen bonding in these thermosets has been shown to correlate with solubility, diffusivity and permeability of water but however does not affect the density, glass transition temperature, Young's modulus or the thermal expansion coefficients. The reasoning for the correlations reported herein provide a fundamental understanding of the relationship between the properties and the molecular structure of the thermoset.