Description

1,1,1,3,3,5,5,7,7,9,9-Undecamethylpentasiloxane is a high-purity linear methyl siloxane oligomer, valued for its excellent thermal stability, low surface tension, and high compressibility. This organosilicon compound serves as a versatile intermediate and functional fluid in advanced material science and specialty chemical manufacturing. It is essential for formulators and manufacturers in the silicone polymers, personal care, and electronics industries seeking reliable performance modifiers.

Application

• Silicone Fluid Intermediate: A key building block for synthesizing higher molecular weight polydimethylsiloxanes (PDMS) and custom silicone copolymers.
• Personal Care & Cosmetics: Used as a volatile carrier, emollient, and conditioning agent in antiperspirants, hair care products, and skin creams due to its smooth, non-greasy feel.
• Release Agents & Lubricants: Functions as a base fluid or additive in mold release formulations and high-temperature lubricants for industrial processes.
• Electronics & Thermal Management: Employed as a heat transfer fluid or a component in thermally conductive greases and encapsulants for electronic assemblies.
• Water Repellents & Surface Treatment: Acts as a hydrophobizing agent for textiles, paper, and construction materials to impart water resistance.
• Defoamers & Antifoams: Serves as an active ingredient in silicone-based defoamer concentrates for various industrial processes, including pulp/paper and wastewater treatment.
• Research & Development: A valuable reagent for organic synthesis and material science research, particularly in developing novel silicone-based materials.

Basic Information

Product Name	1,1,1,3,3,5,5,7,7,9,9-Undecamethylpentasiloxane
CAS No.	17066-04-5
Molecular Formula	C11H34O4Si5
Molecular Weight	370.84 g/mol
Synonyms	Undecamethylpentasiloxane; MD5M; Pentasiloxane, 1,1,1,3,3,5,5,7,7,9,9-undecamethyl-; Linear Pentamer; Methyl-terminated Pentamer; Decamethyltetrasiloxane, trimethylsilyl terminated; Me3SiO[SiMe2O]4SiMe3
EINECS	241-155-5

Quality Control

Our 1,1,1,3,3,5,5,7,7,9,9-Undecamethylpentasiloxane is manufactured under a strict quality management system. Every batch undergoes comprehensive analytical testing, including Gas Chromatography (GC), to ensure high purity and consistent performance. A detailed Certificate of Analysis (COA) confirming identity, assay, and impurity profiles is provided with each shipment to support your quality assurance protocols.

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 oxidizing agents, strong acids, and strong bases. The container should be kept tightly sealed when not in use to prevent moisture absorption and maintain product integrity.

Specification

Item	Specification
Appearance	Colorless clear liquid
Identification (IR)	Conforms to structure
Assay (GC)	≥ 98.0%
Refractive Index (n20D)	1.390 - 1.395
Density (20°C)	0.91 - 0.93 g/cm³
Water Content (KF)	≤ 0.1%

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