Pyrogenic Nano Silica Powder , 99 Percent Purity Organic Silica Powder

Hydrophilic and Hydrophobic Fumed Silica

Description

1, Fumed silica, also known as pyrogenic silica because it is produced in a flame, consists of microscopic droplets of amorphous silica fused into branched, chainlike, three-dimensional secondary particles which then agglomerate into tertiary particles. The resulting powder has an extremely low bulk density and high surface area. Its three-dimensional structure results in viscosity-increasing, thixotropic behavior when used as a thickener or reinforcing filler.

2, Fumed Silica divide into Hydrophilic fumed silica, hydrophobic fumed silica. Hydrophilic fumed silica is manufactured by hydrolysing volatile chlorosilanes in an oxyhydrogen flame. In chemical terms, the loose white powder consists of highly pure amorphous silicon dioxide. Hydrophilic silica is wetted by water and can be dispersed in water. Hydrophobic fumed silica is produced by the chemical modification of hydrophilic with reactive silanes, e.g. chlorosilanes or hexamethyldisilazane. It has water-repellent properties and is no longer dispersible in water.

Process

One production method for the production of fumed silica involved a continuous flame hydrolysis technique. It involves the conversion of silicon tetra chloride (SiCl4) to the gas phase using an oxy hydrogen flame. It then reacts with water to yield silica (SiO2) and hydrochloric acid thus:

THERMAL or PYPOGENING SILICA (FUMED SILICA) 1000℃

SiCL4+2H2+O2→SIO2+4HCL

Properties

1, Reinforcing filler in elastomers.

2, Rheology and thixotropy control of liquid systems,binders,polymers,etc.

3, Used as anti-setting, thickening, anti-sagging agent.

4, Improvement of free flow and anti-caking characteristics of powders.

5, High r transparency

Application

1, Paints and Coatings

2, Unsaturated polyester resins and films

3, Elastomers, especially HTV and RTV Silicone rubber

4, Adhesives and Sealants

5, Printing Inks

6, Plant Protection

7, Cosmetics