Product Overview

Vinyltrimethoxysilane

CAS No.: 2768-02-7

Vinyltrimethoxysilane (CAS No. 2768-02-7) is a vinyl-functional silane coupling agent widely used to enhance adhesion, crosslinking, and moisture resistance in polymer systems. The vinyl group participates in free-radical polymerization, peroxide curing, or grafting reactions with polymers such as polyethylene, EVA, EPDM, and silicone rubber, while the trimethoxysilane groups rapidly hydrolyze and bond to inorganic substrates including glass, silica, metal oxides, and mineral fillers. Owing to its high reactivity and fast hydrolysis, Vinyltrimethoxysilane is extensively applied in wire & cable insulation, rubber compounding, plastics, coatings, sealants, and composite materials to improve mechanical strength and long-term durability.

Chemical NameVinyltrimethoxysilane
CAS No.2768-02-7
EINECS No.220-449-8
Empirical FormulaC₅H₁₂O₃Si
Molecular Weight148.23 g/mol

Synonyms : Vinyltrimethoxysilane / Trimethoxyvinylsilane / Vinyl methyl silicate / Vinyl-functional silane / VTMS / Z-6301 / KH-171 / A-171

Category : Organosilicon Chemicals / Silanes / Functional Silanes / Vinyl Silane ; Vinyl Functional Silane / Silane Coupling Agent / Unsaturated Organosilane / Trialkoxy Silane / Functional Organosilicon Intermediate

Product Description

Vinyltrimethoxysilane (CAS No. 2768-02-7) is a highly reactive vinyl-functional silane coupling agent used to create durable chemical bridges between inorganic substrates and organic polymer matrices. The vinyl group readily participates in free-radical polymerization, peroxide curing, and grafting reactions with polymers such as polyethylene, EVA, EPDM, silicone rubber, and unsaturated resins, while the trimethoxysilane groups rapidly hydrolyze and condense with hydroxylated surfaces including glass, silica, metal oxides, ceramics, and mineral fillers to form robust Si–O–Si / Si–O–M bonds.

Due to its fast hydrolysis rate and high reactivity, Vinyltrimethoxysilane delivers efficient coupling and crosslinking at low dosage levels, resulting in enhanced adhesion, improved mechanical properties, superior moisture resistance, and long-term durability. It is extensively used in wire & cable insulation (moisture-curing and peroxide systems), rubber and plastics compounding, coatings, sealants, and composite materials where strong bonding and processing efficiency are required.

Specifications

ItemSpecification
AppearanceColorless to pale yellow clear liquid
Purity≥ 97% (typical commercial grade ≥95%)
Density (25 °C)~0.95–0.98 g/cm³
Viscosity (25 °C)Low
Boiling Point~123–125 °C
Flash Point~23–27 °C (flammable liquid)
SolubilitySoluble in alcohols and most organic solvents; reacts with water
Refractive Index (25 °C)~1.392–1.398
Hydrolyzable Methoxy Content~55–58 wt%
Moisture SensitivityHighly moisture-sensitive (trimethoxy silane)
Storage Stability12 months in tightly sealed original container
Recommended StorageCool, dry, well-ventilated area; protect from moisture, heat, and ignition sources

Note: Specifications are subject to agreement and may be adjusted according to specific customer or application requirements.

  • Vinyl-functional silane enabling participation in free-radical polymerization, peroxide curing, and grafting reactions
  • Trimethoxysilane groups provide rapid hydrolysis and strong chemical bonding to hydroxylated inorganic surfaces
  • Dual-reactivity mechanism effectively couples organic polymers with inorganic fillers or substrates
  • High reactivity allows efficient performance at low addition levels
  • Widely adopted, industry-standard vinyl silane with extensive global use
  • Significantly improves adhesion between polymers and glass, silica, metal oxides, and mineral fillers
  • Enhances crosslinking efficiency in peroxide- and moisture-curing systems
  • Improves mechanical strength, abrasion resistance, and dimensional stability
  • Increases moisture resistance and long-term aging performance
  • Enables faster processing due to rapid hydrolysis and coupling
  • Proven reliability in high-volume industrial applications such as wire & cable
  • Wire & Cable: moisture-curing and peroxide-crosslinked polyethylene (XLPE), insulation and jacketing compounds
  • Rubber Compounds: EPDM, silicone rubber, and unsaturated rubber systems
  • Plastics & Composites: mineral-filled thermoplastics and thermosets
  • Coatings & Sealants: adhesion promotion on inorganic substrates
  • Glass Fiber & Mineral Filler Treatment: improved dispersion and reinforcement
  • Silicone Rubber Systems: grafting and crosslinking aid
ItemDescription
Chemical NameVinyltrimethoxysilane
CAS No.2768-02-7
Molecular FormulaC₅H₁₂O₃Si
Molecular Weight148.23 g/mol
Chemical TypeVinyl-functional trialkoxy silane
Physical StateLiquid
AppearanceColorless to pale yellow transparent liquid
OdorMild characteristic odor
Density (25 °C)~0.95–0.98 g/cm³
Viscosity (25 °C)Low
Boiling Point~123–125 °C
Flash Point~23–27 °C
Vapor PressureRelatively high compared with higher-boiling silanes
SolubilitySoluble in alcohols and most organic solvents; reacts with water
HydrolysisTrimethoxy groups hydrolyze rapidly in the presence of moisture
CondensationForms Si–O–Si / Si–O–M networks on inorganic surfaces
StabilityStable when dry and sealed; highly moisture-sensitive

Application Methods

  • Direct addition: rubber, plastic, and wire & cable compounds
  • Surface treatment: glass fiber, silica, mineral fillers
  • Pre-hydrolyzed application: primers and slurry treatment where uniform coupling is required

Typical Dosage Ranges

  • Rubber / plastic compounding:

    • 0.5–2.0 wt% based on polymer or filler content

  • Filler / fiber surface treatment:

    • 0.5–1.5 wt% based on filler or fiber weight

Processing Notes

  • Vinyl groups participate directly in peroxide curing and grafting reactions
  • Fast hydrolysis requires strict moisture control during storage and processing
  • Avoid prolonged exposure to humid air to prevent premature condensation
ItemInformation
GHS ClassificationFlammable Liquid; Skin Irritation; Eye Irritation
Signal WordDanger
Hazard StatementsH225: Highly flammable liquid and vapor; H315; H319
GHS PictogramFlame / Exclamation Mark
PPEChemical-resistant gloves, goggles, protective clothing; good ventilation
Handling NotesKeep away from heat, sparks, open flame; avoid moisture
Storage ConditionsCool, dry, well-ventilated area; tightly sealed containers
IncompatibilitiesWater/moisture, strong oxidizers
UN NumberUN 1993 (commonly classified as flammable liquid; check SDS)
TransportADR / IMDG / IATA: Flammable liquid regulations apply
PackagingSteel or HDPE drums
DocumentationSDS available upon request (controlling document)

Q1: What is Vinyltrimethoxysilane mainly used for?
It is used as a vinyl silane coupling agent to improve adhesion, crosslinking, and durability in rubber, plastics, wire & cable, and composite materials.

Q2: How does it differ from Vinyltriethoxysilane (VTES)?
Trimethoxy silanes hydrolyze faster than triethoxy types, offering higher reactivity but requiring stricter moisture control during handling and processing.

Q3: Why is it widely used in wire & cable applications?
Its vinyl group participates in peroxide or moisture-curing reactions, improving crosslink density and moisture resistance in polyethylene insulation systems.

Q4: What substrates does it bond to effectively?
Glass, silica, alumina, mineral fillers, and metal oxides with surface –OH groups.

Q5: Is it moisture sensitive?
Yes. Vinyltrimethoxysilane hydrolyzes rapidly in the presence of moisture and must be stored in tightly sealed containers.

Q6: Is it flammable?
Yes. It is typically classified as a highly flammable liquid, and appropriate storage and transport precautions are required.

Q7: Typical performance benefits?
Improved adhesion, higher mechanical strength, better filler reinforcement, enhanced moisture resistance, and longer service life.

Packaging & Storage

Packaging:  500 g / 1 kg / 5 kg / 25 kg / 200 kg drums / 1000L IBC container (Customized packaging is available).

Storage:

  • Store in tightly sealed original containers
  • Keep in a cool, dry, and well-ventilated area
  • Protect from moisture, humidity, and direct sunlight
  • Avoid contact with water, acids, and oxidizing agents
  • Recommended storage temperature: ambient conditions

Shelf Life:  12 months from date of manufacture when stored under recommended conditions.

Disclaimer

“The information provided herein is based on general industry experience and is intended for reference purposes only. Actual performance and optimal usage conditions may vary depending on formulation, processing methods, substrate characteristics, and end-use requirements. Users are responsible for conducting their own tests and evaluations to determine suitability for their specific applications. No warranty, express or implied, is made regarding the completeness, accuracy, or applicability of this information.”

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