Measurement of pressure dependence on the shear viscosity of polymer melts

We built a rheometer which has a simple structure and can measure the pressure dependence of the viscosity consuming small amount of sample. Main part of the rheometer consists of two sample chambers connected through a slit channel in which two pressure transducers and a pressure adjusting valve are mounted. The double piston arrangement enables to use the materials over and over by the reciprocating flow of the polymer melts from one chamber to the other chamber. The viscosity of polymer melts can be measured at wide range of shear rate and pressure with only about 3 g sample. The pressure coefficients of various polymers are measured by the designed equipment. Measured values are compared to reported values and provide a good agreement.