Hexamethylcyclotrisiloxane(D3) CAS 541-05-9 [(CH₃)₂SiO]₃

What is Hexamethylcyclotrisiloxane(D3)

Hexamethylcyclotrisiloxane is an organosilicon compound with the chemical formula [(CH₃)₂SiO]₃, which is a colorless and transparent liquid at room temperature, and it belongs to cyclic siloxane. The molecule consists of three silicon atoms and three oxygen atoms alternately connected to form a six-membered ring, each silicon atom connected to two methyl groups, structural symmetry and stability. Hexamethylcyclotrisiloxane is liquid at room temperature, but may form knots at low temperatures. The phase change characteristics at different temperatures affect its transportation and storage conditions, and anti-freezing or heat preservation measures need to be selected according to specific applications.
 According to the difference of synthesis method, it can be divided into hydrolysis condensation method and cracking method products. Hydrolysis condensation method hydrolyzes dimethyldichlorosilane to generate cyclic bodies, which may contain tetracyclic, pentacyclic and other congeners, and need to be purified by distillation. Cracking method is generated by high-temperature cracking of high molecular weight polysiloxanes, which has higher purity but higher energy consumption.

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Application of Hexamethylcyclotrisiloxane(D3)

Hexamethylcyclotrisiloxane (D3) is widely used as a core silicone intermediate in silicone rubber, silicone oils and surface treatment agents. In the silicone rubber industry, D3 generates methyl vinyl silicone rubber through ring-opening polymerization, which is used for seals, insulation materials, and as a structuring control agent to prevent silicone rubber storage hardening. Its derivatives, low-viscosity hydroxyl silicone oils, are used in fiber and fabric finishing, plastic additives and filler silanization. In the field of surface treatment, D3 acts as a coupling agent, cross-linking agent and surfactant to improve the interfacial properties of materials, and is used in electronic component coatings, textile waterproofing treatments, and cosmetic volatile carriers (e.g., hair care products).
In addition, D3 is used to prepare polysiloxanes by anionic ring-opening polymerization or by pulsed plasma chemical vapor deposition (PECVD) to generate insulating biomaterial films for semiconductor device encapsulation and medical device coatings. In industrial synthesis, D3 is used as a precursor for organosilicon resins, silica and special silicon compounds to support the development of high-performance materials in aerospace, military defense and other fields. Its low raw material cost and high reactivity (compared with DMC) promote its core position in the silicone industry chain.