Silicones & Silicates
REACH
Methyltrimethoxysilane
CAS Number
1185-55-3
EC Number
214-685-0
Abbreviation
MTMS
What is Methyltrimethoxysilane?
Methyltrimethoxysilane (CAS 1185-55-3), commercially known as MTMS, is a reactive organosilane monomer used to modify surfaces, crosslink polymer networks, and improve adhesion between organic and inorganic substrates.
Where is Methyltrimethoxysilane used?
- Silicone synthesis: building block
- Composites and coatings: coupling agent
- Coatings and sealants: crosslinker and water-repellent surface modifier
- Electronics: hydrophobic, dielectric thin films on semiconductor components and circuit boards
- Adhesives and elastomers: moisture-cure systems and bond strength between polymer matrices and inorganic fillers
- Personal care: MTMS-derived silicones give water-resistant, smooth-feel finishes in hair and skin products
- It improves durability and adhesion to glass, metal, and mineral substrates.
Commercial specifications
- Standard packaging from drums to ISO tank containers for bulk orders
- Technical and high-purity grades
- Purity typically 97% or higher; higher-purity lots with controlled moisture content for electronics and specialty coatings
Other Names (Synonyms)
MTMS|Trimethoxy(methyl)silane|Silane, trimethoxymethyl-|Z 6070|0HI0D71MCI|GLASCA B|A 163
What are the physical properties of Methyltrimethoxysilane?
Melting Point -78 °C
Boiling Point 102-103 °C
Density 0.955 g/cm³
Flash Point 52 °F
Appearance Colorless clear liquid
Color colorless
Odor Mild odor
Form liquid
Water Solubility decomposes
Vapor Pressure 2990 hPa (20 °C)
Refractive Index n 20/D 1.371(lit.)
Log P -2.4-0.7 at 20℃
How is Methyltrimethoxysilane classified and handled safely? Learn More
Danger
GHS02· Flammable GHS07· Irritant GHS05· Corrosive GHS08· Health Hazard
Hazard Statements
H225 Highly Flammable liquid and vapor
H315 Causes skin irritation
H317 May cause an allergic skin reaction
H318 Causes serious eye damage
Precautionary Statements
P210 Keep away from heat, hot surfaces, sparks, open flames and other ignition sources. No smoking.
P233 Keep container tightly closed.
P240 Ground and bond container and receiving equipment.
P241 Use explosion-proof [electrical/ventilating/lighting/…] equipment.
Which trade and regulatory codes apply to Methyltrimethoxysilane?
HS Code 29310095
UN Number 1993
ADR Class 3
Packing Group II
Storage Class 3 - Flammable liquids
WGK (Germany) 3