This work is aimed to study the diffusion process in oriented nanocomposites, characterized by the presence of permeable lamellar stacks, by FEM analysis. To this purpose, a geometrical model, based on a random distribution of non-interpenetrating stacks, was used to calculate the coefficient of diffusion. The main novelty of the developed analysis is that each nanofiller particle is made by a stack of individual platelets, separated by galleries of varying thickness. Consequently, the nanofiller particles are not considered to be completely impermeable to the diffusing species, thus allowing to account for mass transport between stacks, as well as within each stack. Simulations were run at different nanocomposites morphologies, varying nanofiller volume fraction, orientation angle, lamellar gallery thickness and number of platelets in each stack. An analytical model was developed, which is able to predict the evolution of coefficient of diffusion as a function of the four morphologic features of the nanocomposites. The developed model can account for the multi scale diffusion mechanism, showing a very good agreement with the simulation data. The developed analytical model was used to estimate the orientation angle of graphene stacks in epoxy matrix by comparison with experimental permeability data.
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