Description

Octadecyltrimethoxysilane is a long-chain organosilane coupling agent widely used to impart hydrophobic and organophilic properties to inorganic surfaces. Its primary value lies in its ability to form durable, water-repellent coatings and to compatibilize organic polymers with inorganic fillers like silica and minerals. This product is essential for manufacturers in the coatings, plastics, and construction industries seeking to enhance material performance, adhesion, and moisture resistance.

Application

• Surface Modification Agent: Used to hydrophobize and improve the dispersibility of inorganic fillers (e.g., silica, calcium carbonate, glass fibers) in polymer composites.
• Waterproofing Additive: A key component in sealants, coatings, and construction materials for concrete, stone, and masonry to provide long-lasting water repellency.
• Adhesion Promoter: Enhances the bonding between organic resins (epoxy, polyurethane) and mineral substrates or metal surfaces in adhesive and coating formulations.
• Rubber & Tire Industry: Acts as a coupling agent in silica-filled rubber compounds to reduce rolling resistance and improve mechanical properties.
• Nanomaterial Functionalization: Used to modify the surface of nanoparticles (e.g., TiO2, SiO2) for specialized applications in electronics and advanced materials.
• Textile & Leather Treatment: Imparts durable water and oil repellency to fabrics, leather, and non-woven materials.
• Paper Sizing Agent: Improves the water resistance and printability of paper and paperboard products.

Basic Information

Product Name	Octadecyltrimethoxysilane
CAS No.	3069-42-9
Molecular Formula	C21H46O3Si
Molecular Weight	374.68 g/mol
Synonyms	n-Octadecyltrimethoxysilane; Stearyltrimethoxysilane; Trimethoxy(octadecyl)silane; OTS; Silane A-18; Dynasylan 9116; 3-(Trimethoxysilyl)-1-octadecane; Octadecyltri(methoxy)silane
EINECS	221-304-1

Quality Control

Our Octadecyltrimethoxysilane is manufactured under strict quality management systems. Each batch undergoes rigorous analytical testing to ensure consistent purity and performance, meeting the specifications required for industrial and specialty chemical applications. A Certificate of Analysis (COA) detailing key parameters such as assay, identity, and impurity profile is provided with every shipment to guarantee supply reliability and product consistency.

Storage

Preserve in a tightly closed container, protected from light. Store in a cool, dry, and well-ventilated area at room temperature (15-25°C). This material is hygroscopic (moisture-sensitive). Keep the container tightly sealed under a dry inert atmosphere (e.g., nitrogen) to prevent hydrolysis and degradation upon contact with atmospheric moisture.

Specification

Item	Specification
Appearance	Colorless to pale yellow liquid
Identification (IR)	Conforms
Assay (GC)	≥ 97.0%
Density (20°C)	0.88 - 0.90 g/cm³
Refractive Index (n20D)	1.428 - 1.432

Note: Specifications can be tailored. Please contact us for the detailed technical data sheet of a specific grade.