LUDOX® Colloidal Silica

LUDOX® colloidal silica is composed of discrete, amorphous, spherical silica nanoparticles in an aqueous dispersion. These particles do not exhibit detectable levels of crystallinity or porosity. Several grades are available with particle sizes ranging from 5 to 40 nanometers. Each grade of LUDOX® colloidal silica has a very tight particle size distribution and varies in pH, silica sol charge, density, and stabilizing mechanism. Most LUDOX® grades have silica particles with a negative surface charge and are stabilized in high pH using sodium, ammonium, or hydrogen ions. Some LUDOX® grades have a positive particle surface charge and are stabilized in low pH by chlorine ions. LUDOX® provides many essential functionalities in chemical formulations and processes for several industries, including coatings, paints, refractories, concrete, catalysts, and paper.

Smaller-particle-size grades tend to increase physical strength and durability in paint, coating, refractory, and catalyst applications through a binding mechanism that leverages the silanol groups on the high surface area of LUDOX® particles. These silanol groups create bonds with various metallic, ceramic, polymeric, and organic materials when drying into a solid via a special form of a sol–gel reaction. For waterborne paint and coating applications, LUDOX® is used as a binder or cobinder with organic polymers, fillers, substrates, and other silica particles to increase the strength and durability of films. In refractory applications, LUDOX® particles bind strongly to themselves and metal oxide particles to form materials with high-temperature stability and chemical and thermal shock resistance. Catalysts and molecular sieves can be made using LUDOX® as a raw material source of silica or be reinforced with it to increase hardness and attrition resistance. In concrete applications, the small particle size of LUDOX® allows it to penetrate deeply into concrete, react with free lime, and create calcium silica hydrates, which densify and strengthen the concrete.

Larger particle sizes of LUDOX® colloidal silica provide the best results when used as surface-modifying additives. When larger-particle-size grades are used in coatings, LUDOX® will increase antiblocking, adhesion, and dirt-pickup resistance. These larger particles will also increase friction on a variety of surfaces, including paperboard and linerboard, textiles, and floors. When added to paper, it will also increase ink receptivity and wetting.

Many other commercial applications are possible for LUDOX® colloidal silica. See below to learn more about the available grades and their recommended uses. To learn more about the most common applications for LUDOX®, view product articles about LUDOX® by selecting Grace as the manufacturer using the filter located on the left using the following link. https://www.chempoint.com/insights