Molecular dynamics simulation of reinforcement of mechanical properties of nitrile rubber by adding nano-zirconia

Abstract

The molecular model of nano-zirconia reinforced nitrile rubber （NBR） composite was established by molecular dynamics simulation. The reinforcement effects of three forms of nano-zirconia, namely, external filling, in-situ filling, and in-situ filling and coupling treatment on mechanical pro-perties of NBR were compared and analyzed, internal reinforcement mechanism of the mechanical properties of stator rubber was discussed from atomic level. The results showed that compared with pure NBR, the mechanical properties of NBR were significantly improved by introduction of three forms of nano-zirconia. The surface hydroxyl of in-situ filled nano-zirconia interacted with NBR to form hydrogen bond type dipole interaction. The addition of surfactant coupling agent bis-（3-triethoxysilane propyl） tetrasulfide further provided a chemical bridge with the rubber matrix, thus greatly improving the mechanical properties of NBR matrix. Compared with pure NBR system, the nano-zirconia filled in situ and treated by coupling had the best performance in enhancing the mechanical properties of NBR, and the young's mo-dulus, volume modulus and shear modulus of the composite system were improved the most. The conclusion that the addition of nano-zirconia improved the mechanical properties of stator rubber was verified by calculating the interface binding energy, non-bond energy, mean square displacement and diffusion coefficients.

Keywords

• nitrile rubber
• nano-zirconia
• mechanical property
• molecular dynamics simulation