A novel theoretical strategy for modeling viscosity of polymer melts: Modified friction theory with PC-SAFT

Abstract

Despite its importance, the role of pressure in the viscosity of polymer melts is little known. A modified friction theory (f-theory) combined with perturbed-chain statistical association fluid theory (PC-SAFT) was proposed to model the dynamic viscosity of polymer melts under high pressure and shear rate. Viscosity data points were collected from literature and analyzed. Different estimation strategies for PC-SAFT parameters for polymers were assessed from the perspective of molecular weight. The resulted appropriate parameters were used to calculate the attractive and repulsive pressures of the polymers, and the pressures were then used as inputs of both linear friction model and modified f-theory for viscosity modeling. The parameters of two models were obtained by fitting to the experimental viscosity data. The overall average absolute relative deviation (AARD) of the modified f-theory for viscosity modeling is 4.42%, which indicates the good modeling performance of the modified f-theory.