Rubber Field Info

Rubber Field Info

Hydrophilic & Hydrophobic Silica

Silica inherently possesses hydrophilic properties, but hydrophobic silica is obtained through modifications with hydrophobic groups. Hydrophilic silica is typically added to aqueous systems, where it exhibits good dispersion. However, when hydrophilic silica is added to organic systems, it does not disperse well. In contrast, hydrophobic silica can disperse effectively in organic systems, ensuring a homogeneous distribution.

Hydrophilic Silica

Hydrophilic silica is produced through the hydrolysis of volatile chlorosilane in an oxyhydrogen flame. Chemically, these loose white powders consist of highly pure amorphous silica. Hydrophilic silica can easily wet and disperse in water. In addition to its conventional applications in industries like polyester, silicone, paint, and coatings, hydrophilic silica products are increasingly finding success in high-tech fields.

The nano-particle characteristics and high purity of silica make it a leading choice for applications in the electronics and optical fiber industries. X-ray analysis confirms that hydrophilic fumed silica products have an amorphous structure. To cater to different markets and application fields, silica products with various particle sizes and specific surface areas are available. Some fumed silica products can be compressed and supplied, while others meet medical-grade standards.

The functions of hydrophilic silica include facilitating processing and achieving desirable rheological properties, reinforcing silicone elastomers, thickening non-polar liquids, acting as flow aids in food and industrial powder applications, offering high chemical purity, delivering excellent insulation performance even at high temperatures, and enabling the transformation of liquids into powders, as seen in medicine and cosmetics.

Hydrophobic Silica

Hydrophobic silica is produced through a chemical reaction between hydrophilic silica and an active silane, such as chlorosilane or hexamethyldisilazane. Various types of hydrophobic silica have been developed to address specific technical challenges encountered in different industries.

One method involves treating modified hydrophilic silica with silane or siloxane, where the chemical treatment agent forms a chemical bond with the original hydrophilic oxide. Hydrophobic silica offers advantages beyond those of hydrophilic products, including low moisture absorption, excellent dispersion, and the ability to regulate rheology even in polar systems. Some hydrophobic silica products undergo structural modifications to further assist customers in developing new products and enhancing performance.

Hydrophobic silica, also referred to as white carbon black, serves various functions, such as providing suitable rheology during processing and usage, thickening polar liquids like epoxy resin, reinforcing silicone elastomers, facilitating high loading levels in molded products, improving corrosion resistance through enhanced hydrophobicity, enhancing dielectric properties in cable composites, acting as a flow aid in powder coatings and fire extinguishing agents, and increasing scratch resistance in coatings and plastics.

Due to its versatile capabilities, hydrophobic silica proves to be valuable across a wide range of applications. It meets specific requirements and enhances performance in industries such as coatings, plastics, electronics, and more, offering solutions to address technical needs and improve overall product performance.

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