Dynasylan® A

Dynasylan® A is the ethyl ester of orthosilicic acid.
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.

Typical Applications

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

Benefits at a glance

Dynasylan® A is an important starting material for sol-gel processes, where the additional use of alkylalkoxysilanes (e. g. Dynasylan® MTES) can give the siloxane network a somewhat organic character as a result of the incorporation of alkyl groups.
It is also possible to construct an inorganic/organic network by adding silanes containing organofunctional groups (e.g. aminopropyl groups) and polymerizing with organic precursors. This principle makes it possible to obtain highly scratch- and abrasion-resistant coatings.

Product Details

Technical Data Sheets

Further Information

Storage:

Dynasylan® A must be stored with exclusion of moisture.

Packaging:

Dynasylan® A is supplied in 25 kg or 190 kg drums or in 850 kg containers.

Shelf life:

In a sealed container, Dynasylan® A has a shelf-life of min. 12 months from delivery.