Modeling and characterization of viscoelasticity of PI/SiO2 nanocomposite films under constant and fatigue loading

In this paper, the viscoelastic behavior of PI/SiO2 nanocomposite thin films under constant and fatigue tensile loading was studied. The cyclic hardening and viscous dissipation of PI/SiO2 nanocomposite thin films during the fatigue process were experimentally investigated and analyzed by storage modulus, loss modulus and phase lag. The time-dependent deformation under constant and fatigue loading was simulated based on two viscoelastic models known as Burger model and Findley power law. Standard parameter analysis methodology was employed to interpret the structure–property relationship and deformation mechanisms of this kind of nanocomposites. In addition, the effects of nano-silica content, stress level and loading pattern (constant or fatigue loading) on the creep resistance of materials were discussed as well.