Description

Hexatriacontamethylcyclooctadecasiloxane is a high molecular weight, cyclic siloxane oligomer, specifically a member of the polymethylcyclosiloxane family. This compound is valued for its exceptional thermal stability, low volatility, and hydrophobic properties, making it a crucial functional fluid and intermediate in advanced material synthesis. It is primarily utilized by manufacturers in the silicone polymer, specialty lubricant, and personal care industries seeking high-performance organosilicon components. The CAS number for this substance is 23523-12-8.

Application

• As a high-temperature heat transfer fluid or base stock for specialty lubricants and greases.
• Acting as a key intermediate or chain extender in the synthesis of high-consistency silicone rubbers (HCR) and other silicone polymers.
• Utilized as a surface treatment agent or hydrophobic coating precursor for textiles, fillers, and pigments.
• Functioning as a plasticizer and processing aid in silicone elastomer and resin formulations to improve flow and mold release.
• Employed as a volatility suppressor and emollient in high-end personal care products and cosmetics.
• Serving as a dielectric fluid in specific electrical or electronic applications requiring stable, non-conductive media.
• Used in research and development as a model compound for studying siloxane chemistry and polymer behavior.

Basic Information

Product Name	Hexatriacontamethylcyclooctadecasiloxane
CAS No.	23523-12-8
Molecular Formula	C36H108O9Si18
Molecular Weight	1335.9 g/mol
Synonyms	Cyclooctadecasiloxane, hexatriacontamethyl-; D18; Octadecamethylcyclononasiloxane (common misnomer); Cyclic Volatile Methyl Siloxane, cVMS (D18); Polymethylcyclosiloxane; Cyclomethicone D18; 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-1,3,5,7,9,11,13,15,17-nonasilaoctadecane
EINECS	Contact for details

Quality Control

Our Hexatriacontamethylcyclooctadecasiloxane is produced under a strict quality management system. Each batch undergoes rigorous analytical testing, including Gas Chromatography (GC) and Gel Permeation Chromatography (GPC), to ensure consistent purity, molecular weight distribution, and the absence of critical impurities. A comprehensive Certificate of Analysis (COA) detailing assay, identity, and specific parameters is provided with every shipment to guarantee compliance with your technical requirements.

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 the container tightly sealed when not in use to minimize exposure to moisture and atmospheric contaminants. Store away from strong bases and incompatible materials such as strong oxidizing agents.

Specification

Item	Specification
Appearance	Colorless to pale yellow viscous liquid
Identification (IR)	Conforms to reference spectrum
Assay (GC)	≥ 95.0% (D18 main component)
Molecular Weight (GPC)	1300 - 1370 g/mol
Refractive Index (20°C)	1.398 - 1.402
Density (25°C)	0.96 - 0.98 g/cm³
Volatile Matter	≤ 1.0%
Water Content (KF)	≤ 0.1%

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