Structure property correlation of epoxy resins under the influence of moisture; and comparison of diffusion coefficient with MD-simulations

The properties of epoxy based materials alter, when exposed to humid environment and temperature. To better understand the failure mechanisms on microelectronic packaging we examine these epoxies (aromatic epoxy: l,3-Bis-(2,3-epoxypropyl)-benzene and amine hardener: 1,2-Diaminoethan ) under different initial conditions of temperature (300-400 K) & humidity (85,100 RH) and change systematically the structure (stoichiometry & molecular weight). By applying the previous conditions we perform mechanical characterization (glass transition temperature-Tg & coefficient of thermal expansion - CTE), make diffusion experiments to obtain the diffusion coefficient D , the water uptake-wt%, the hygroscopic strain epsiv and do molecular dynamics-(MD) simulations to calculate the D and compare them with experiment. Diffusion coefficients are calculated under NVT - thermodynamic boundary conditions by using a classical force-field MD. It was found that changing the free-volume and/or polarity of the structure does influence the properties and molecular dynamics predicted qualitatively the influence of structure on D.