Siloxanes & Silazanes

Short siloxanes and silazanes are the building blocks and finishing agents of silicone chemistry. A disiloxane caps the ends of a growing chain and sets its length; a disilazane replaces active hydrogen with a trimethylsilyl or vinyldimethylsilyl group, which is why it is called a silylating agent. Neither is usually the finished product — both decide what the finished product becomes.

Siloxanes

Hexamethyldisiloxane is the standard trimethylsilyl end-capper for silicone fluids, and a volatile solvent in its own right. Tetramethyldivinyldisiloxane caps chains with vinyl groups — the reactive ends of vinyl fluids and raw rubbers — and is a ligand in the platinum catalysts used for addition cure. Heptamethyltrisiloxane carries one Si–H group, through which polyether, epoxy, amino or alkyl groups are grafted to make modified silicone fluids. Octaphenylcyclotetrasiloxane is a source of diphenylsiloxane units for phenyl silicone rubber.

• SF-SO62 Hexamethyldisiloxane
• SF-SO42 Tetramethyldivinyldisiloxane
• SF-SO73 Heptamethyltrisiloxane
• SF-SO83 Octamethyltrisiloxane
• SF-SO84 Octaphenylcyclotetrasiloxane

Silazanes

Hexamethyldisilazane (HMDS) silylates hydroxyl and amine groups. It hydrophobises fumed silica and other fillers, controls structuring in silicone rubber, primes wafers for photoresist, and protects functional groups in pharmaceutical synthesis. Tetramethyldivinyldisilazane introduces vinyl groups onto filler surfaces for liquid silicone rubber, and heptamethyldisilazane is a protecting agent in fine-chemical synthesis.

• SF-SN62 Hexamethyldisilazane
• SF-SN42 Tetramethyldivinyldisilazane
• SF-SN72 Heptamethyldisilazane

Handling

Silazanes react with water and release ammonia, so they are kept dry and under inert gas once opened. The volatile siloxanes are flammable. Each product's SDS gives the details.

For purity grades, a COA or an SDS, contact our sales team.