 |
The viscosity of an aqueous Walocel® M solution is defined by the frictional resistance of a fluid to shear forces or to compressive stress, hence to flow. The viscosity is determined using, for instance, rotary viscometers, Höppler viscometers or Brookfield viscometers and is stated Pas or mPa·s. Depending on the method applied, the viscosity stated may vary considerably. A viscosity of 70000 mPa·s measured in a 2% aqueous solution at 20°C and a shear rate of 2.55 1/s using a rotary viscometer corresponds to approx. 300000 mPa·s when measured with a Höppler viscometer even though the concentration and temperature is the same. On request we are pleased to send you the Walocel® M Visco-Navigator.
Within the various product categories, Walocel® methyl cellulose is available in wide selection of mean viscosity ranging from 400 mPa·s to the high-viscosity grades of 70000 mPa·s. Our products with a mean viscosity above 1000 mPa·s are measured with Haake Rotovisko RV 100 viscometers at a constant shear rate of D = 2.55 1/s at 20°C in a 2% solution. Walocel® M grades with a viscosity of less than 1000 mPa·s are measured using Höppler viscometers (2% solution).
The properties of Walocel® M are essentially based on the specific behaviour of Walocel® M solutions in water. The Walocel® M solutions are pseudoplastic and - at higher concentration levels - thixotropic.
The pseudoplastic (non-Newtonian) flow properties of Walocel® M in solution regulate the rheology of building material systems and therefore their consistency and workability. Even by using very small quantities of methyl cellulose, it is possible to selectively control crucial quality features.
| |
