Test EquipmentDevelopment of a pressure-driven micro-rheometer

A pressure-driven micro-rheometer was developed. It uses 80 mg of material to measure the viscosity of polymer melts at shear rates ranging from 10 to several thousands s−1. The maximum shear rate can be extended to several 104 s−1 with 200 mg of sample. The main part of the rheometer consists of two sample reservoirs connected through a slit channel (H=0.1 mm, W=1 mm, L=5 mm) and two pistons. The double piston arrangement enables one to use the same material repeatedly by the reciprocating flow of the polymer melt from one reservoir to the other. In addition, by using a very thin slit channel, the viscosity of polymer melts can be measured over a wide range of shear rates whilst using only a small quantity of material. Measured viscosity was in good agreement with that by a capillary rheometer, and it was found that slip was negligible in the slit die used in this study.