Trimethylsilyl treated silica

Trimethylsilyl treated silica (CAS 68909-20-6) is a surface-modified fumed or precipitated silica whose surface hydroxyl groups have been capped with trimethylsilyl groups.

Where is Trimethylsilyl treated silica used?

• Coatings and adhesives: rheology modifier controlling sag, thixotropy and flow in solvent-borne and UV-cure formulations
• Silicone sealants and elastomers: reinforcement and anti-settling performance
• Rubber compounding: improved dispersion and processing consistency where moisture uptake would compromise cure behaviour
• Plastics and construction sealants: anti-caking and flow aid in powder systems
• It serves as a foam suppressant in reactive resin applications.

Good to know: The trimethylsilyl treatment renders the particle hydrophobic, unlike untreated silica, which performs poorly in non-aqueous and moisture-sensitive systems. Product differentiation is typically based on BET surface area, carbon content and degree of hydrophobic treatment.

Commercial specifications

• Fumed and precipitated silica substrates used as base material