Abstract: During the measurement of melt viscosity, the pressure would change throughout the process, and the accuracy of shear viscosity was affected. The filtering algorithm was chosen to adapt the changes of system to filter the pressure and the temperature through experiments and theoretical analysis. The digital filter was done to improve the final accuracy of polymer melt viscosity. Through the use of recursive average algorithm, the measurement accuracy of polymer melt shear viscosity was significantly improved.

Key words: shear viscosity, digital filter technology, online rheometer, signal processing, measurement accuracy, polymer