Investigation of the flow behaviors of carbon nanotubes dispersed epoxy resin with modified bi-mode FENE dumbbell simulation

In this study, a modified bi-mode finitely extensible non-linear elastic (FENE) dumbbell model was introduced to investigate the concentration-dependent and shear-rate-dependent viscosity of carbon nanotubes (CNTs) dispersed polymer solutions. It is called bi-mode because the aggregated CNTs and free CNTs are considered as two different types of CNTs with different mobility. The diffusion coefficient was simulated by classical molecular dynamics (MD) simulation and input into the FENE models. For the steady shear flow, the coupled Fokker–Planck equations and the corresponding stress tensors were solved numerically. The influence of CNT diameter and CNT mass on the shear viscosity was discussed. In addition, the bi-mode FENE dumbbell simulation can be applied to investigate the shear viscosity under different shear rates and increase of shear viscosity with time evolution. With the model, the influence of the anisotropy parameter, finite extensibility parameter was investigated. The shear-rate-dependent viscosity profile of resin solutions with different CNT concentrations was also predicted and validated with experimental rheological behavior. The simulation model can provide qualitative prediction of rheological behavior of CNTs dispersed resin.