AHTP-1200

Technical Data Sheet: Antmee® Hydrogen Terminated Polydimethylsiloxane Series

Product Name: Antmee® Hydrogen Terminated Polydimethylsiloxane
Chemical Description: Hydride Terminated Polydimethylsiloxane / α,ω-Dihydride Polydimethylsiloxane
CAS Number: 70900-21-9 
Molecular Structure: H-Si(CH₃)₂O-[Si(CH₃)₂O]n-Si(CH₃)₂-H 

1. Product Overview

Antmee® Hydrogen Terminated Polydimethylsiloxane is a series of clear, colorless linear polysiloxane fluids featuring reactive silicon-hydride (Si-H) functional groups at both polymer chain ends. Unlike conventional methyl-terminated silicone oils which are chemically inert, the terminal Si-H bonds confer high reactivity, making these fluids essential building blocks for synthesizing silicone-organic copolymers and precisely structured silicone materials via hydrosilylation chemistry 。

The bifunctional nature of Antmee® Hydrogen Terminated PDMS enables it to serve as a chain extender, crosslinker, or macromonomer in addition-cure silicone systems. When reacted with vinyl-functional silicones or organic vinyl monomers in the presence of a platinum catalyst, the terminal Si-H groups form stable ethylene bridges, permanently incorporating the flexible siloxane segment into the target polymer backbone or network 。The series is available in discrete molecular weight grades from 1,250 to 20,000, allowing formulators precise control over the siloxane block length, crosslink density, and ultimate mechanical properties of the final material 。

2. Typical Physical & Chemical Properties

The following specifications represent the general physical properties of the Antmee® Hydrogen Terminated Polydimethylsiloxane series. Actual values vary depending on the molecular weight grade selected.

• Appearance: Colorless, clear transparent liquid (Visual) 

• Active Content: ≥ 99% 

• Density (at 25°C): Approx. 0.97 – 0.98 g/mL 

• Refractive Index (at 25°C): Approx. 1.390 – 1.410 

• Flash Point: > 93°C (varies with molecular weight) 

• Volatility: ≤ 5% for grades with MW > 1,250 (150°C/3h) 

• Hydrogen Content: Inversely proportional to molecular weight; lower MW grades contain higher Si-H content and thus exhibit higher reactivity 

• Solubility: Soluble in common aromatic and aliphatic organic solvents; insoluble in water

Disclaimer: Typical values are representative of average production lots and should not be interpreted as guaranteed batch-specific specifications. Minor variations are expected due to normal manufacturing tolerances.

3. Standard Specifications by Molecular Weight Grade

Please refer to the specific Antmee® product code for detailed Certificate of Analysis (CoA) data, including precise Si-H content, viscosity, and molecular weight distribution.

Antmee® H-PDMS-1250 (Molecular Weight: 1,250)
This is a low molecular weight, low-viscosity grade characterized by relatively high Si-H content (approx. 0.16% hydrogen, 1.6 mmol/g SiH) 。The high reactive group density makes Antmee® H-PDMS-1250 an excellent choice as a chain extender in addition-cure liquid silicone rubber (LSR), where it increases elongation and toughness without significantly increasing formulation viscosity 。It is also ideal for synthesizing short-block silicone-organic copolymers and for surface modification applications requiring a thin, reactive silicone interlayer.

Antmee® H-PDMS-2000 (Molecular Weight: 2,000)
A standard low molecular weight grade offering a balance of reactivity and handling ease. Antmee® H-PDMS-2000 contains approximately 0.1% hydrogen (1.0 mmol/g SiH) and exhibits a viscosity around 25 cSt 。This grade is widely used as a key intermediate in block copolymer synthesis and as a reactive diluent in platinum-catalyzed silicone formulations. It provides a slightly longer siloxane segment than the 1,250 MW grade, imparting incrementally greater flexibility to the final polymer.

Antmee® H-PDMS-13000 (Molecular Weight: 13,000)
A medium-high molecular weight grade that delivers a substantially extended polydimethylsiloxane block. The Si-H content is reduced relative to lower MW grades, resulting in fewer crosslink or coupling sites per unit mass. Antmee® H-PDMS-13000 is ideally suited for synthesizing high-performance silicone-organic copolymers where a pronounced degree of silicone softness, flexibility, and hydrophobicity is desired. It serves as an effective macromonomer for modifying polyurethanes, polyamides, and epoxy resins to enhance weatherability and low-temperature impact resistance.

Antmee® H-PDMS-15000 (Molecular Weight: 15,000)
A high molecular weight grade engineered for applications requiring maximum siloxane block length with terminal reactivity. The low Si-H content ensures that crosslinking or chain extension occurs primarily at the chain ends, preserving the inherent mobility and flexibility of the long PDMS segment. This grade is recommended for premium block copolymer synthesis and as a reactive internal lubricant for engineering thermoplastics.

Antmee® H-PDMS-20000 (Molecular Weight: 20,000)
The highest molecular weight standard grade in the Antmee® Hydrogen Terminated PDMS series. Antmee® H-PDMS-20000 provides the ultimate in silicone character with minimal reactive end-group concentration. It is the preferred choice for applications where a large, flexible, and highly hydrophobic siloxane block must be tethered into an organic matrix, including advanced thermoplastic elastomers, high-durability foul-release coatings, and specialized personal care ingredients 。

4. Primary Applications

• Silicone-Organic Copolymer Synthesis: Serves as the essential Si-H functional building block for creating silicone-polyether, silicone-polyurethane, silicone-polyamide, and silicone-epoxy block and graft copolymers via platinum-catalyzed hydrosilylation 。These hybrid materials combine the benefits of silicones with organic polymer compatibility.

• Addition-Cure Silicone Elastomers: Functions as a chain extender in LSR and RTV formulations to increase the distance between crosslink junctions. This improves elongation at break, enhances tear resistance, and reduces modulus and hardness of the cured elastomer 。

• Polymer Modification: Acts as a reactive modifier for organic polymers, imparting improved weatherability, UV stability, low-temperature flexibility, and internal lubrication without the migration and surface blooming issues associated with non-reactive silicone additives 。

• Surface Treatment and Functionalization: Used to covalently tether a well-defined silicone layer onto organic or inorganic substrates (e.g., silica, glass, carbon black) bearing vinyl or allyl functionality. Provides durable hydrophobicity, release properties, and biocompatibility.

• Pharmaceutical and Personal Care: Precursor for synthesizing specialized silicone-based excipients, emulsifiers, and conditioning agents where precise molecular architecture and high purity are required.

5. Packaging and Storage Information

• Packaging Options: Available in 20 kg pails, 50 kg HDPE drums, or 200 kg lined steel drums depending on molecular weight and volume requirements. Custom packaging available upon request 。

• Shelf Life: 12 months from the date of manufacture when stored in the original, unopened container under recommended conditions 。

• Storage Conditions: Store in a cool, dry, and well-ventilated area away from direct sunlight, moisture, and sources of heat or ignition. Keep containers tightly sealed to prevent contamination and unintended reaction with atmospheric moisture. Recommended storage temperature range: 5°C to 35°C. Avoid contact with strong bases, acids, and transition metal salts which may catalyze unintended Si-H condensation or disproportionation reactions 。