A non-Newtonian fluid model with finite stretch and rotational recovery

• We provide a non-Newtonian fluid model with finite stretch and rotational recovery.
• All model parameters are linked to corresponding physical processes.
• The model simultaneously predicts shear thinning and extensional thickening.
• Model predication shows excellent agreement with experimental data.

Recently, we proposed a non-Newtonian fluid model containing two separate relaxation processes to treat straining ad material rotation and demonstrated good fitting to realistic rheological functions of polymeric flow. The model described in the present paper is an extension and improvement of the previous model. Particularly, a different approach is adopted to handle the effects of finite stretch on the basis of finite chain dynamics. The resulting model shows excellent fitting to experimental results with fewer model parameters than the previous model. All model parameters are linked to corresponding physical processes and can be readily determined from standard rheological plots. This study also revealed several interesting relations between rheological functions that are worth further investigations.