Prediction of loss factor (tan δ) for polymer nanocomposites as a function of yield tress, relaxation time and the width of transition region between Newtonian and power-law behaviors.

Abstract

This article develops a simple model for loss or damping factor (tan δ) in polymer blends and nanocomposites as a function of yield tress, relaxation time, power-law index and the width of transition region between Newtonian and power-law behavior. The predictions of the developed model are compared to the experimental results of loss factor for the blends and nanocomposites containing poly (lactic acid) (PLA), poly (ethylene oxide) (PEO) and carbon nanotubes (CNT). Moreover, the significances of all parameters on the loss factor are justified to confirm the developed model. The calculations of developed model properly agree with the experimental results at all frequency ranges and the model's parameters reasonably change in blends and nanocomposites. A poor yield stress, short relaxation time, low power-law index and large transition region between Newtonian and power-law behavior grow the loss factor. The rational roles of these parameters in the loss factor validate the developed model.