The understanding of inter-diffusion between fiber sizing and a matrix is an important mechanism governing interphase formation during composite processing. Diffusion governs the concentration gradients, interphase thickness and the resulting atomic structure and properties of the interphase. Epoxy film former and Jeffamine curing agents are two main constituents of the matrix and sizing phases, respectively. In this study, the inter-diffusion between an Epoxy film former (Epon) and Jeffamine curing agents are investigated by performing a series of molecular dynamic simulations using general AMBER force field (GAFF) classical interatomic potential. In the simulations, Epon and Jeffamine phases are initially combined to form a discrete boundary followed by relaxation, tracking of molecules and the creation of concentration profiles. All simulations are performed over a wide range of temperatures. Simulation results indicate that inter-diffusion is Fickian type and temperature dependent inter-diffusion follows Arrhenius law. Inter-diffusion coefficients at room temperature are on the order of 10~(-8) cm~2/s. The use of short term data to predict long time scale diffusion and interphase morphology is assessed.
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