Hydroxy-terminated Silicone Oil, also known as Hydroxy-terminated Polydimethylsiloxane (HO-PDMS), is a reactive linear silicone polymer widely used as a fundamental building block in the silicone industry. Because the polymer chains contain terminal hydroxyl groups (–OH), this material can easily undergo crosslinking, modification, and compounding to produce a wide range of silicone products.

With excellent thermal stability, electrical insulation, and compatibility with fillers, hydroxy-terminated silicone oil is used across industries such as construction, electronics, chemicals, mold-making, and textiles.

What Is Hydroxy-Terminated Silicone Oil?

Hydroxy-terminated silicone oil is a colorless, transparent, odorless silicone fluid composed of polydimethylsiloxane (PDMS) with hydroxyl groups at both ends of the molecular chain.

These functional hydroxyl groups allow the polymer to react with crosslinkers like silanes, siloxanes, and curing agents, making it an essential raw material for room-temperature vulcanized (RTV) silicone rubber and modified silicone systems.

It is commonly produced in viscosities ranging from 100 cSt to 50,000 cSt depending on customer requirements.

Key Features and Benefits

Hydroxy-terminated silicone oil is favored for its versatile performance characteristics, including:

• Excellent thermal resistance (–50°C to +200°C)

• Superior electrical insulation, suitable for electronic components

• Outstanding chemical, UV, and weather resistance

• Low surface tension, providing superb spreading and wetting properties

• High transparency and non-toxicity

• Reactive end groups for crosslinking and modification

• Compatibility with silica and common silicone additives

These advantages make it one of the most widely used reactive silicone polymers in industrial manufacturing.

Main Applications of Hydroxy-Terminated Silicone Oil

1. RTV Silicone Rubber Production

Hydroxy-terminated silicone oil is the backbone material for:

• One-component (RTV-1) silicone sealants

• Two-component (RTV-2) silicone mold rubbers

• Encapsulation and potting materials

• Adhesive and sealant systems

When used together with fillers and crosslinkers, it forms durable, flexible, and high-performance silicone elastomers.

2. Industrial Silicone Defoamers

Due to its low surface tension and good stability, hydroxy-terminated silicone oil is commonly used in defoamer formulations for:

• Wastewater treatment

• Chemical processing

• Fermentation and food industries

• Paper and pulp production

• High-temperature systems

It helps achieve fast foam knockdown and long-lasting foam control.

3. Water-Repellent & Release Coatings

The hydrophobic nature of silicone provides excellent performance in:

• Textile finishing

• Building surface protection

• Release agents for plastics and rubber

• Anti-sticking and anti-scratch coatings

Hydroxy-terminated silicone oil can be used directly or modified to create specialized functional coatings.

4. Intermediate for Silicone Modification

This silicone fluid is an essential base polymer for producing:

• Emulsified silicone oils

• Amino/epoxy/phenyl modified silicone oils

• Silicone resins

• Heat-resistant silicone rubber

• Specialty silicone additives

Its –OH groups make it highly reactive for secondary synthesis.

Typical Technical Specifications

Specifications may vary by grade, but common parameters include:

• Appearance: Colorless, transparent liquid

• Viscosity (25°C): 100–50,000 cSt

• Hydroxyl Content: 0.08%–1.5%

• Volatile Content: ≤ 0.5%

• Flash Point: ≥ 300°C

• Purity: High-stability polymer with excellent consistency

Conclusion

Hydroxy-terminated Silicone Oil is a versatile, high-performance silicone polymer widely used in sealants, elastomers, coatings, defoamers, and specialty modified silicones. With strong stability, reactivity, and compatibility, it remains a vital raw material for manufacturers across many industries.

If your business needs high-quality hydroxy-terminated silicone oil with consistent performance, we provide customizable specifications, technical support, and professional export solutions.