Abstract Polymer melts are typical non-Newtonian fluids.When measuring the rheological properties of polymer melts using capillary rheometers,the shear rate of the fluid is often corrected for non-Newtonian behavior using the non-Newtonian index value.However,the traditional method for calculating the non-Newtonian index that has raised doubts among students.This paper introducesa new method for calculating the non-Newtonian index in detail and compares the results obtained using both the traditional and the new methods based on experimental data.The results show that the non-Newtonian indices derived from both methods are entirely consistent.Therefore,adopting the new calculation method not only simplifies the determination of the non-Newtonian index but also resolves students’ doubts about the traditional approach.
FAN Ji-Chang, GUO Fu-Quan. Calculation Methods for the Non-Newtonian Index of Polymer Melts[J]. Chinese Journal of Chemical Education, 2026, 47(4): 52-55.
