In such liquids the time delay needed for the viscosity to change suggests that a certain amount of time is needed to re-arrange or align the structural components that results in decrease in the viscosity of the test material. Put in another way, the material shows thinning behaviour with time when it is sheared at a constant rate. Another type of viscous behaviour exhibited by fluid foods and polymer systems is thixtropy which is again shear-thinning of the material with increasing rates of shear, but is also dependent on the duration of shear. This is referred to as time independent (steady state) flow and materials showing this type of behaviour are called pseudoplastic. The viscosity of some fluids is dependent on the rate used to shear the material, a high rate of shear making the fluid thinner compared with the fluid that was sheared more slowly.

If this is not observed then the liquid is non-Newtonian. An easy way to demonstrate Newtonian behaviour is to double the shear stress during a viscosity test and this should result in doubling of the shear rate. Contact Associated Polymer Labs, Inc.Newtonian behaviour is displayed by simple liquids consisting of small molecules that do not interact or form any connected structure. However, it must be pointed out that long chain polymers at low concentration can also show Newtonian behaviour.

The purpose of this specific testing is for product consistency and knowing quality is there.īatch to batch consistency and quality control. ASTM D4889-Standard Test methods for polyurethane raw materials: determination of viscosity of crude or modified isocyanates.īrookfield viscosity of water, solutions, coating materials, liquid/gel adhesives, cosmetics, lotions, and liquid detergents.ASTM D2196-Test methods for rheological properties on non-newtonian materials by rotational Brookfield Viscometer.ASTM D2393-Test methods for viscosity for epoxy resins and related components.ASTM D1824-Test method for apparent viscosity of plastisols and organosols at low shear rates by Brookfield Viscometer.to continually assess their products and keep the quality the best! These companies depend on Associated Polymer Labs, Inc. Example: High Viscosity liquid requires more power to pump than a low viscosity liquidĬompanies depend on Quality of their products and to file Patent claims.Brookfield Viscometer- Viscosity studies are a direct assessment of processibility.

Testing viscosity