Introduction*
Nano-silica particles according to their structure are divided into two types: P-type (Porous particles ) and S-type (Spherical particles). P-type nano-silica surface contains a number of nano-porous with the pore rate of 0.611ml /g; therefore, P-type has much larger SSA comparing to S-type. S-type’s SSA is ~170-200m2/g. Further more, P-type ultraviolet reflectivity is >85% , S-type: >75%.
Test Methods*
- Transmission electron microscopy (TEM) method, nano-silica particle has small size, narrow particle size distribution.
- BET method, nano-silica particle has large specific surface area.
- Infrared spectroscopy method, nano-silica particle exists a large number of hydroxyl groups and unsaturated residual bonds on its surface, and forms the deviation from the steady state of the silicon oxide structure.
- Cary-5E spectrophotometer testing method, nano-silica particles–high reflectivity to long wave and visible light about UV.
- Omnisorp100CX surface area and porosity analyzer, P-type nano-silica surface contains a number of nano-porous with the pore rate of 0.611ml /g.
Synthesis
SiO2 can be synthesized by the following methods:
- Sol-Gel. Stöber process
- Precipitation
- Gas phase
- Milling
General Properties
Applications
The following are the chief applications of silica nanoparticles:
- Anti-blocking agent
- Thixotropic agent
- Strengthening filler for composites materials
- Drug delivery
- Catalyst carrier
Manufacturers
- Avonic-Aerosil.
- SS Nano.
- NanoShel. They also sell a wide range of nano-materials and others
- Tokuyama.
- US-nano.
- Wacker
- 欧克创德 CD Powder
- 苏州优锆纳米材料
- Madhu Silica Precipitated Silica from India
- OCI from Korea
*Cited from www.us-nano.com