EVONIK SILANES

Ethyl polysilicate – Dynasylan 40 is a ethyl silicate with a silicon dioxide content of approximately 40 – 42 % upon complete hydrolysis (the Si content of Dynasylan 40 is calculated as SiO2). Dynasylan 40 is formed in the presence of water from tetraethyl silicate (Si[OEt]4) by partial hydrolysis of the ethoxy groups to hydroxyl groups and subsequent condensation with formation of siloxane bonds (-Si-O-Si-). Dynasylan 40 is a colorless, low-viscosity liquid with an SiO2 content of 40% (the Si content of Dynasylan 40 is calculated as SiO2). The polysilicic acids still have a sufficient content of ethoxy groups which can be activated by acid- or base-catalyzed hydrolysis.

Tetraethylorthosilicate – 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.

Tetrabutylglycolsilicate

Reactive organofunctional siloxane oligomer in water – Dynasylan HYDROSIL 2909 can act as binder or co-binder in water based sol-gel systems. Dynasylan HYDROSIL 2909 is a almost colorless liquid.

Tetra-n-propylsilicate – Dynasylan P is a special silicic acid ester.