Dynasylan® A
Tetraethylorthosilicate
Dynasylan® A is the ethyl ester of orthosilicic acid.
Description
In the literature it is frequently also referred to under the name TEOS (tetraethoxysilane). Dynasylan® A is a colourless, low-viscosity liquid with SiO2 content of 28.5%. Use requires acid- or alkali-catalysed hydrolysis. Since all 4 ethoxy groups are able to participate in this reaction, Dynasylan® A is regarded as tetrafunctional. Hydrolysis leads to silanol groups which, in a subsequent condensation reaction, form very stable siloxane bonds (-Si-O-Si-). Condensation starts before hydrolysis is complete. During storage of these hydrolysates condensation, continues until a gel is formed. The rate of gelation depends on the concentration of water.
Dynasylan® A is a ready source of silicic acid for many applications. Silicic acid in usually obtained by hydrolysis, or thermally by condensation at elevated temperature. The resulting silicic acid bonds well to many inorganic substrates and can be deposited in situ in a controlled manner. The surfaces of glass, metals, pigments, fillers and synthetic fibres can be coated with a very thin SiO2 layer in order to improve chemical and thermal stability and mechanical properties.
Other applications are:
- crosslinkers in silicone rubber systems
- drying agents in sealing compositions
Safety & Handling
Before considering the use of Dynasylan® products please read its Safety Data Sheet (SDS) thoroughly for safety and toxicological data as well as for information on proper transportation, storage and use. The Safety Data Sheet is available after registration on our website www.dynasylan.com or upon request from your local representative, customer service or from Evonik Resource Efficiency GmbH, Product Safety Department, E-MAIL sds-hu@evonik.com.
Packaging and Storage
Dynasylan® A is supplied in 25 kg or 190 kg drums or in 850 kg containers.
Dynasylan® A must be stored with exclusion of moisture.
In a sealed container, the product has a shelf-life of min. 12 months from delivery.