SemiSIL R202: Hydrophobic Fumed Silica (PDMS Treated)
SemiSIL R202 is a premium PDMS treated fumed silica engineered for maximum moisture resistance and rheology stability. By chemically bonding silicone oil to the silica surface, R202 eliminates the "structuring" effect in rubber and ensures consistent viscosity in polar resins like epoxy and vinyl esters.
Quick Profile
- Surface Treatment: PDMS (Polydimethylsiloxane)
- Surface Area (BET): 100 ± 20 m²/g
- CAS Number: 112945-52-5
- Carbon Content: 3.5% - 5.5%
- Key Advantage:Ultimate anti-structuring performance, superior polarity stability, and maximum moisture protection.
Strategic Applications & Solutions
Silicone Rubber
Functions as a premier anti-structuring agent for silicone rubber, preventing crepe hardening during storage while enhancing mechanical reinforcement.
Adhesives & Sealants
Provides superior rheology control for vinyl ester resins and epoxy adhesives, ensuring zero viscosity drop and high thixotropy in polar systems.
Cable Gels
The essential hydrophobic silica for cable gels, offering maximum moisture resistance and stable dielectric properties for long-term insulation.
Coatings & Powder Materials
Acts as an efficient anti-caking agent for powder coatings and provides precise anti-sagging for vertical structural coatings.
Key Functional Properties
Advanced Surface Shielding
The PDMS treated fumed silica structure effectively masks surface silanol groups, eliminating unwanted chemical reactions with polymers and preventing crepe hardening.
Polar Resin Compatibility
As a high-performance PDMS treated fumed silica, it offers superior rheological stability in epoxy and vinyl ester resins, preventing viscosity aging over long-term storage.
Ultimate Moisture Barrier
With high carbon content (3.5%~5.5%), this PDMS treated fumed silica provides a permanent hydrophobic shield, essential for cable gels and electronic encapsulants.
Thixotropic & Anti-Sagging Control
SemiSIL R202 functions as an elite PDMS treated fumed silica rheology modifier, creating a robust 3D network that ensures perfect anti-sagging and pigment suspension in vertical applications.
Technical Data (TDS)
| Property | Standard Value | Unit | Method |
|---|---|---|---|
| Specific Surface Area (BET) | 100 ± 20 | m²/g | GB/T 20020 |
| pH Value (in 4% dispersion) | 4.0 ~ 7.0 | - | GB/T 20020 |
| Carbon Content | 3.5 ~ 5.5 | Wt% | GB/T 20020 |
| Loss on Drying (2h @ 105°C) | ≤ 0.5 | Wt% | GB/T 20020 |
| Loss on Ignition (2h @ 1000°C) | 4.0 ~ 6.0 | Wt% | GB/T 20020 |
| Tamped Density | 40 ~ 60 | g/L | GB/T 20020 |
| Silica Content (SiO₂) | ≥ 99.8 | % | GB/T 20020 |
Packaging & Logistics
Non-DG Compliance: Fully safe for Railway, Sea (Shipping), and Truck transportation.
20'FCL Loading
• 180kg / pallet (18 bags)
• 10 pallets / 1600kg total
• 10 pallets / 1600kg total
40'HQ Loading
• 220kg / pallet (22 bags)
• 20 pallets / 4400kg total
• 20 pallets / 4400kg total
Common Questions about PDMS Treated Fumed Silica R202
Is SemiSIL R202 a direct equivalent to Aerosil® R202?
Yes. SemiSIL R202 is a 1:1 technical replacement for industry-standard PDMS treated grades. It matches the carbon content and BET surface area requirements, ensuring a seamless transition for users of PDMS treated fumed silica in adhesives and silicone rubber.
How does R202 function as an anti-structuring agent for silicone rubber?
SemiSIL R202 acts as a specialized anti-structuring agent for silicone rubber by using its PDMS coating to shield surface silanol groups. This prevents the "crepe hardening" effect during storage, keeping your rubber compounds soft and processable even at high filler concentrations.
Why is R202 preferred for rheology control in vinyl ester resins and epoxies?
Unlike DDS-treated grades, this PDMS treated fumed silica provides superior rheology control for vinyl ester resins and epoxy systems. Its silicone oil treatment is highly compatible with polar resins, preventing the common "viscosity aging" issue where the product thins out over time.
What makes R202 the ideal hydrophobic silica for cable gels?
With a high carbon content of 3.5%~5.5%, SemiSIL R202 is the ultimate hydrophobic silica for cable gels. Its high hydrophobicity silica with 100 BET profile ensures a permanent moisture barrier and dielectric stability, critical for protecting fiber optic and communication cables.
What is the main difference between PDMS and DDS treated silica?
The difference between PDMS and DDS treated silica lies in the treatment agent's chain length. PDMS treated fumed silica (R202) uses long-chain silicone oil for maximum hydrophobicity and anti-structuring, while DDS (R272) uses shorter chains. R202 is superior for rubber and polar resins requiring long-term shelf stability.
Factory-Direct hydrophobic fumed silica R202
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