Coarse-grained Field Parameters Calibration of CNT/PI Composites Based on Constant Strain Method.

A coarse-grained mapping scheme of polyimide (PI) and carbon nanotube (CNT) was designed, and the coarse-grained field parameters of CNT/PI-based composites were obtained by the constant strain method based on the conservation of the total strain energy. The accuracy of coarse-grained field parameters is verified by comparing the matching degree between the simulation results of all-atom and coarse-grain. The tensile stiffness of CNT and PI molecular chains, the interface interaction between CNT and PI matrix, and the Young's modulus of CNT/PI composite were simulated by field parameters. The results showed that the coarse-grained field parameters obtained by the constant strain method could accurately reflect the mechanical properties of nanocomposites. The effects of the equilibrium distance (r₀) and well parameters (D₀) of Van Der Waals potential function on the density of the model, the interface interaction between CNT and PI matrix, and the Young's modulus of the nanocomposite were discussed. The results showed that the increase of r₀ reduce the density of the model. The interfacial interaction between CNT and PI matrix and the Young's modulus of nanocomposites could improve when D₀ increased. [ABSTRACT FROM AUTHOR]