Effect of initial imbibed moisture content on flexural fatigue behavior of polyamide 66/hectorite nanocomposites at laboratory condition

Imbibed moisture affects the mechanical properties of polymers and influences the performance of products made out of them during service. Flexural fatigue tests were conducted under deflection control mode using a custom built, table-top flexural fatigue test rig at laboratory condition on PA66/hectorite nanocomposites (PA66CN). Dynamic mechanical analysis studies of PA66CN revealed significant plasticization effect of water on moduli and damping factor with increase in imbibed moisture content. A decrease in induced flexural stress amplitude and rise in temperature of specimen with increase in moisture content result in increased fatigue life at a constant cyclic end deflection. The microstructure of failed flexural fatigue specimens manifested a rubbery behavior. The extent of rubberiness is directly related to the difference between specimen temperature at cyclic steady state and glass transition temperature.