Study On Certified Reference Materials System Of Non-Newtonian Fluid Viscosity

Non-Newtonian fluid exist in nature widely.The flow of polymer solution,suspension colloid and most of biological fluid presents non-Newtonian behavior.The viscosity measurement of non-Newtonian fluid is of great significance in industrial production.Because the viscosity value changes with the shear rate,rotational viscometers or rheometers are usually used to measure the viscosity of non-Newtonian fluid.The principle of rotational viscosity measurement is more complex than that of capillary viscometer.There are many parameters to be controlled and many factors that may introduce uncertainty components.At present,the complete non-Newtonian viscosity traceability chains have not been established over the world.Several countries,including China and Germany,have carried out research on the technology of rotaional rheometer/viscometer traceability and the development of non-Newtonian certified reference materials(CRMs).The shear rate of the rheometer can be traced to the national standard of rotational speed,and the shear stress can also be traced to the standard torque device by combination of a special pulley block and weights.Compared with the Newtonian fluid CRMs,the accuracy of the viscosity value of the rotational rheometer has been confirmed.Therefore,the traceability of rotational rheometer has been solved by the above means in our laboratory.The development of non-Newtonian CRMs is an important part of the establishment of a complete metrological traceability chain for non-Newtonian fluid viscosity measurement in China.Non-Newtonian CRMs could be used to delivery values from standard to routine testers of viscosity of non-Newtonian samples,and a guarantee for the measurement value unification of non-Newtonian fluid viscosity measurement in China.In this paper,polyisobutylene/white oil system,dimethylsilicone oil systevm,polyethylene oxide aqueous solution,dextran aqueous solution and polyacrylamide aqueous solution system were measured and analysed by a stress-controlled rotational rheometer,a series of CRM ingredients with behavior of non-Newtonian flow has been obtained,including water-based solution with low viscosity and oil-based system with high viscosity.These non-Newtonian CRMs could cover a huge range of viscosity,and have obvious characteristic of non-Newtonian fluids.This study has important reference value for the determination of non-Newtonian fluid viscosity standard candidate.