Methyltrimethoxysilane (MTMS)

Methyltrimethoxysilane (MTMS) is a clear, colorless, moisture-sensitive organosilane used as a silicone resin intermediate, crosslinker and mineral surface modifier. It hydrolyzes in contact with water, releasing methanol.

Brand:
aozun
Synonym:
Methyltrimethoxysilane
Appearance:
colorless clear liquid
CAS No.:
1185-55-3
Molecular Formula:
CH3Si(OCH3)3
Molecular Weight:
136.22 g/mol
EINECS:
214-685-0

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Product Description

Product Description

Key Specifications and Typical Properties

Item	Value
CAS No.	1185-55-3
EC No.	214-685-0
Molecular Formula	C₄H₁₂O₃Si
Structural Formula	CH₃Si(OCH₃)₃
Molecular Weight	136.22 g/mol
Appearance	Clear, colorless liquid
Boiling Point	Approximately 102°C
Density	Approximately 0.95 g/mL at 25°C

Physical values are indicative. Purity and other acceptance limits are confirmed in the agreed specification and current COA.

MTMS has three hydrolyzable methoxy groups. Hydrolysis forms silanol groups, which can condense into siloxane structures. Reaction behavior depends on factors including pH, concentration, temperature and catalyst.

Applications

1. Coatings and Paints

Sol-gel coatings: Precursor for methyl-containing siloxane and hybrid coating networks.
Formulation development: Used where the coating design requires controlled crosslinking or surface modification.

2. Sealants and Adhesives

Crosslinking: Ingredient in selected alkoxy-cure silicone formulations.
Moisture management: Can function as a moisture scavenger in compatible systems.

3. Construction Materials

Mineral treatment: Raw material for formulated water-repellent treatments.
Performance assessment: Substrate, penetration, curing conditions and durability should be evaluated for the intended application.

4. Silicone Resins

Resin intermediate: Supplies methyl-bearing units for siloxane resin networks.
Hybrid systems: Can be used with other suitable silane or silica precursors.

5. Filler and Pigment Treatment

Surface modification: Used to make suitable inorganic surfaces more hydrophobic.
Dispersion: Can assist pigment or filler dispersion in compatible formulations.

Packaging and Storage

Packaging: 200 kg drums; confirm other packing options with the quotation.
Storage: Keep tightly sealed in a cool, dry, well-ventilated area, protected from moisture and ignition sources.
After opening: Minimize exposure to humid air and reseal promptly to reduce premature hydrolysis.

Safety and Handling

Fire control: Highly flammable liquid and vapor. Eliminate ignition sources and control static during transfer.
Hydrolysis byproduct: Contact with moisture releases methanol. Use suitable ventilation and avoid inhalation or direct contact.
Protection: Select gloves and eye protection for the task. Follow the current grade-specific SDS for complete health hazards, exposure controls and disposal requirements.

Frequently Asked Questions

Can MTMS Be Added Directly to a Water-Based Formulation?

Direct addition may cause premature hydrolysis and condensation. Use a validated incorporation method and assess formulation stability and methanol release.

What Is the Difference Between MTMS and MTES?

MTMS contains methoxy groups, while methyltriethoxysilane (MTES) contains ethoxy groups. MTMS generally reacts faster with water under comparable conditions. Substitution requires evaluation of the hydrolysis and curing process.

Can MTMS Replace an Aminosilane or Epoxysilane?

Not automatically. MTMS has a methyl substituent, whereas aminosilanes and epoxysilanes carry additional reactive organic groups. Select the silane according to the substrate, resin chemistry and curing mechanism.