Description

Octadecamethylcyclononasiloxane is a high-purity, cyclic siloxane oligomer, specifically a nonamer, valued for its well-defined molecular structure and consistent performance. This compound serves as a critical intermediate and functional fluid in advanced material synthesis, offering excellent thermal stability and low surface tension. It is essential for manufacturers in the silicone polymer, personal care, and specialty lubricant industries seeking precise molecular building blocks.

Application

• Silicone Polymer Intermediate: A key precursor for the synthesis of custom silicone oils, resins, and elastomers with controlled molecular weight and properties.
• Personal Care & Cosmetics: Used as an emollient and conditioning agent in high-end skincare, haircare, and antiperspirant formulations for a smooth, non-greasy feel.
• Release Agents & Molding: Functions as a base fluid in mold release agents for plastics, rubber, and composite materials manufacturing.
• Specialty Lubricants: Employed in high-performance lubricants and greases for applications requiring thermal stability and water repellency.
• Dielectric & Heat Transfer Fluids: Suitable for use in specialized electronic cooling systems or as dielectric fluids due to its insulating properties.
• Surface Treatment & Coatings: Acts as a hydrophobizing agent or additive to improve slip, gloss, and water resistance in various coatings.

Basic Information

Product Name	Octadecamethylcyclononasiloxane
CAS No.	556-71-8
Molecular Formula	C18H54O9Si9
Molecular Weight	667.38 g/mol
Synonyms	Cyclononasiloxane, octadecamethyl-; D9; Octadecamethylcyclononasiloxane; Cyclic Volatile Methyl Siloxane (cVMS) D9; Decamethylcyclopentasiloxane (common misnomer, correct for D5); 2,2,4,4,6,6,8,8,10,10,12,12,14,14,16,16,18,18-Octadecamethyl-1,3,5,7,9,11,13,15,17,2,4,6,8,10,12,14,16,18-nonaoxa-2,4,6,8,10,12,14,16,18-nonasilacyclooctadecane
EINECS	209-136-7

Quality Control

Our Octadecamethylcyclononasiloxane is produced under a strict quality management system. Each batch undergoes comprehensive analytical testing, including Gas Chromatography (GC) for purity and identity confirmation, to ensure it meets stringent specifications for high-purity intermediates. Certificates of Analysis (COA) detailing all test results are available upon request to support your quality assurance and regulatory compliance needs.

Storage

Preserve in a tightly closed container, protected from light. Store in a cool, dry, well-ventilated area at room temperature (15-25°C). Keep away from strong acids, bases, and oxidizing agents. For long-term storage, consider under an inert atmosphere to maintain purity.

Specification

Item	Specification
Appearance	Colorless clear liquid
Identification (IR)	Conforms to reference
Assay (GC)	≥ 98.0%
Refractive Index (n20/D)	1.395 - 1.398
Density (g/mL, 25°C)	0.955 - 0.965
Water Content (KF)	≤ 0.05%

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