Exilva Microfibrillated Cellulose vs. Fumed silica: anti-settling benefits from effective yield stress
Ole Martin Kristiansen | June 11, 2019
Exilva microfibrillated cellulose and fumed silica are both used for controlling the rheology of liquid systems, such as anti-settling and anti-sedimentation. But when we are comparing the two technologies, we also see differences. In this article, we will show you how the microfibrillated cellulose and fumed silica builds yield stress, and how they consequently can give good anti-settling and anti-sedimentation benefits.
Yield stress as an indicator of anti-settling and anti-sedimentation benefits
Exilva microfibrillated Cellulose and fumed silica are both used for anti-settling and anti-sedimentation. When we compare the two technologies for this functionality, we need to define the yield stress of the materials.
Table 1: Yield stress values for a TiO2 pigment dispersions with 0.5% active material.
Type of Additive
Yield Stress (Pa)
Exilva F 01-V
Commercially available fumed silica
In the table above you can find the example of exactly this, where the yield stress of the two materials are shown in the same dispersion, indicating the potential of the materials on the anti-sag properties as well as the stability of a formulation and/or dispersion.
The table shows yield stress values for water-based titanium oxide (TiO2) pigment dispersions containing Exilva F 01-V (microfibrillated cellulose) and commercially available fumed silica. Exilva has a superior yield stress at the same active content, which gives an indication of improved anti-sag properties as well as anti-settling and anti-sedimentation. This is most likely due to the highly effective interaction of the 3D-network Exilva has when in a pigment formulation compared to the fumed silica.
How can I add Exilva microfibrillated cellulose to test for yield stress and anti-sedimentation/anti-settling?
Exilva microfibrillated cellulose is used in a wide array of areas with paints & coatings. For paint & coating producers, the optimal place to add Exilva microfibrillated cellulose is during the grinding step. By ensuring a sufficient dispersion of the fibers, by utilizing the high shear forces in the grinding step, you will succeed in incorporating the yield stress properties of Exilva microfibrillated cellulose into your coating system.
For other application areas using fumed silica today, the important thing to remember is to introduce Exilva microfibrillated cellulose where enough shear forces are present.
Ole Martin Kristiansen
Ole Martin is the Marketing Manager of Exilva in Borregaard. He holds a bachelor's degree in Media Management and has been with the company since 2017.