VINYLTRIETHOXYSILANE

Vinyltriethoxysilane manifests as a mobile, pale straw-colored liquid with a less pungent odor compared to its methoxy analog—a consequence of the larger, less volatile ethoxy groups. 
The extended alkyl chains impart distinct physicochemical properties including reduced polarity, increased hydrophobicity, and modified solvent interactions. 
The compound exhibits favorable wetting characteristics on both polar and non-polar substrates, with a contact angle on clean glass of approximately 20-25°.
 
Systematic Identification:
 IUPAC Nomenclature: Ethenyltriethoxysilane
 Chemical Abstract Service Registry: 78-08-0
 Molecular Architecture: C₈H₁₈O₃Si
 Structural Representation: CH₂=CH–Si(OC₂H₅)₃
 Molecular Mass: 190.31 g/mol ± 0.03 g/mol
 
Melting Point: < -70°C (remains liquid to very low temperatures)
Boiling Point: 160-163°C at 1013 hPa (narrow boiling range indicates high purity)
Vapor Pressure: 1.5 hPa at 20°C; 3.2 hPa at 30°C (significantly lower than VTMS)
Heat of Vaporization: ~45 kJ/mol
Autoignition Temperature: ~280-300°C
Dielectric Constant: ~4.2 at 20°C (1 kHz)
Detailed Chemical Behavior and Reactivity:
 VTES represents a more controlled, deliberate variant of vinylsilane chemistry—the ethoxy substituents providing a moderating influence on reactivity while maintaining essential functionality. This balance makes VTES exceptionally versatile for applications requiring precise processing control.
Hydrolysis Kinetics – Comparative Analysis:
 The hydrolysis of ethoxysilanes proceeds through the same fundamental mechanism as methoxysilanes but with distinct kinetic differences:
Half-life at 25°C, 50% RH: ~8-12 hours (4-6 times slower than VTMS)
Activation energy: ~65 kJ/mol (vs. ~55 kJ/mol for VTMS)
Solvent effects: Hydrolysis rates in aqueous ethanol follow the trend: methanol > ethanol > isopropanol
Catalysis: Acid catalysis more pronounced than base catalysis for ethoxysilanes
The slower hydrolysis translates to practical advantages including extended pot life in formulations, more controlled film formation, and reduced sensitivity to atmospheric humidity during processing.
Condensation and Network Formation:
 VTES-derived silanols condense to form siloxane networks with distinctive structural characteristics:
Lower crosslink density compared to VTMS systems (due to steric effects)
Increased flexibility in cured films/networks
Better stress relaxation properties
Reduced susceptibility to microcracking during thermal cycling
Gel permeation chromatography of partially condensed VTES oligomers reveals molecular weight distributions centered around 800-1500 Da for typical pre-condensed formulations.
Polymerization and Grafting Chemistry:
 The vinyl group in VTES participates in all standard vinyl polymerization mechanisms but with modified kinetics due to:
Electron-donating effect of ethoxy groups via silicon (β-effect)
Steric accessibility similar to VTMS
Compatibility differences in various media
Notably, VTES exhibits excellent reactivity in hydrosilylation reactions with Si–H functional silanes and polymers, enabling precise stoichiometric crosslinking in silicone systems.
Surface Modification Mechanisms:
 On inorganic substrates, VTES forms densely packed monolayers with slightly lower surface coverage (2.5-4 molecules/nm²) compared to VTMS, attributable to the larger ethoxy groups. The resulting films exhibit:
Advancing water contact angles of 70-80° after curing
Excellent thermal stability up to 300°C in inert atmosphere
Good chemical resistance to acids (except HF) and bases
X-ray photoelectron spectroscopy (XPS) confirms Si–O–substrate bonding with binding energies of Si(2p) at 102.5-103.0 eV.
Industrial Applications – Expanded Analysis:
Crosslinked Polyethylene (PEX) Manufacturing – In-Depth:
 VTES serves as the predominant crosslinking agent for PEX-b production, representing a sophisticated three-stage process:
Grafting Reaction (Extruder, 180-220°C):
 Peroxide initiator (typically dicumyl peroxide) generates radicals on the polyethylene backbone, which abstract hydrogen atoms, creating macro-radicals. These react with VTES via free-radical addition, grafting the silane onto the polymer chain. Grafting efficiencies typically reach 70-85%.
Processing and Shaping:
 The grafted polymer (containing 1.5-3.0% VTES) can be processed conventionally into pipes, cables, or profiles. The absence of crosslinking during this stage (due to controlled moisture exclusion) maintains thermoplastic behavior.
Moisture-Induced Crosslinking:
 Final products are exposed to hot water or steam (80-95°C), initiating hydrolysis of ethoxy groups followed by condensation between adjacent chains. This creates a three-dimensional siloxane network, transforming thermoplastic polyethylene into an elastomeric thermoset with:
Maximum service temperature increased from 60°C to 95°C
Environmental stress crack resistance improved 10-100x
Creep resistance enhanced by orders of magnitude
Mineral-Filled Thermoplastics Optimization:
 In talc-, calcium carbonate-, or wollastonite-filled polypropylene, VTES acts as a multifunctional interface modifier:
Increases filler loading capacity from 20-30% to 40-60% without sacrificing processability
Improves impact strength by 30-50% through enhanced stress transfer
Reduces viscosity, enabling lower processing temperatures (energy savings of 10-15%)
Enhances UV stability through reduced interfacial degradation
The optimal concentration follows an adsorption isotherm model, typically saturating at 0.5-1.0% VTES based on filler weight.
Hybrid Material Synthesis:
 VTES serves as a precursor for sol-gel derived hybrid materials with tunable properties:
Organic-inorganic hybrids with controlled porosity
Transparent coatings with adjustable refractive index (1.42-1.48)
Gradient materials with spatially varying composition
Nanocomposites with exfoliated clay or other layered materials
The sol-gel process allows molecular-level mixing, resulting in materials with unique combinations of hardness, flexibility, and thermal stability.
Electronic and Electrical Applications:
Encapsulants for microelectronics with controlled modulus
Dielectric coatings for printed circuit boards
Adhesion promoters for conductive inks on flexible substrates
Moisture barriers for organic electronic devices

SAFETY INFORMATION ABOUT VINYLTRIETHOXYSILANE

 
First aid measures:
Description of first aid measures:
General advice:
Consult a physician. 
Show this safety data sheet to the doctor in attendance.
Move out of dangerous area:
 
If inhaled:
If breathed in, move person into fresh air. 
If not breathing, give artificial respiration.
Consult a physician.
In case of skin contact:
Take off contaminated clothing and shoes immediately. 
Wash off with soap and plenty of water.
Consult a physician.
 
In case of eye contact:
Rinse thoroughly with plenty of water for at least 15 minutes and consult a physician.
Continue rinsing eyes during transport to hospital.
 
If swallowed:
Do NOT induce vomiting. 
Never give anything by mouth to an unconscious person. 
Rinse mouth with water. 
Consult a physician.
 
Firefighting measures:
Extinguishing media:
Suitable extinguishing media:
Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide.
Special hazards arising from the substance or mixture
Carbon oxides, Nitrogen oxides (NOx), Hydrogen chloride gas
 
Advice for firefighters:
Wear self-contained breathing apparatus for firefighting if necessary.
Accidental release measures:
Personal precautions, protective equipment and emergency procedures
Use personal protective equipment. 
 
Avoid breathing vapours, mist or gas. 
Evacuate personnel to safe areas.
 
Environmental precautions:
Prevent further leakage or spillage if safe to do so.
Do not let product enter drains.
Discharge into the environment must be avoided.
 
Methods and materials for containment and cleaning up:
Soak up with inert absorbent material and dispose of as hazardous waste. 
Keep in suitable, closed containers for disposal.
 
Handling and storage:
Precautions for safe handling:
Avoid inhalation of vapour or mist.
 
Conditions for safe storage, including any incompatibilities:
Keep container tightly closed in a dry and well-ventilated place. 
Containers which are opened must be carefully resealed and kept upright to prevent leakage.
Storage class (TRGS 510): 8A: Combustible, corrosive hazardous materials
 
Exposure controls/personal protection:
Control parameters:
Components with workplace control parameters
Contains no substances with occupational exposure limit values.
Exposure controls:
Appropriate engineering controls:
Handle in accordance with good industrial hygiene and safety practice.
Wash hands before breaks and at the end of workday.
 
Personal protective equipment:
Eye/face protection:
Tightly fitting safety goggles. 
Faceshield (8-inch minimum). 
Use equipment for eye protection tested and approved under appropriate government standards such as NIOSH (US) or EN 166(EU).
 
Skin protection:
Handle with gloves. 
Gloves must be inspected prior to use. 
Use proper glove
removal technique (without touching glove's outer surface) to avoid skin contact with this product. 
Dispose of contaminated gloves after use in accordance with applicable laws and good laboratory practices. 
Wash and dry hands.
 
Full contact:
Material: Nitrile rubber
Minimum layer thickness: 0.11 mm
Break through time: 480 min
Material tested:Dermatril (KCL 740 / Aldrich Z677272, Size M)
Splash contact
Material: Nitrile rubber
Minimum layer thickness: 0.11 mm
Break through time: 480 min
Material tested:Dermatril (KCL 740 / Aldrich Z677272, Size M)
It should not be construed as offering an approval for any specific use scenario.
 
Body Protection:
Complete suit protecting against chemicals, The type of protective equipment must be selected according to the concentration and amount of the dangerous substance at the specific workplace.
Respiratory protection:
Where risk assessment shows air-purifying respirators are appropriate use a fullface respirator with multi-purpose combination (US) or type ABEK (EN 14387) respirator cartridges as a backup to engineering controls. 
 
If the respirator is the sole means of protection, use a full-face supplied air respirator. 
Use respirators and components tested and approved under appropriate government standards such as NIOSH (US) or CEN (EU).
Control of environmental exposure
Prevent further leakage or spillage if safe to do so. 
Do not let product enter drains.
Discharge into the environment must be avoided.
 
Stability and reactivity:
Chemical stability:
Stable under recommended storage conditions.
Incompatible materials:
Strong oxidizing agents:
Hazardous decomposition products:
Hazardous decomposition products formed under fire conditions. 
Carbon oxides, Nitrogen oxides (NOx), Hydrogen chloride gas.
 
Disposal considerations:
Waste treatment methods:
Product:
Offer surplus and non-recyclable solutions to a licensed disposal company. 
Contact a licensed professional waste disposal service to dispose of this material.
Contaminated packaging:
Dispose of as unused product