SEMISIL 200 Fumed Silica (BET 200 m²/g, Hydrophilic)
Key Features
- Industry-standard 200 m²/g hydrophilic grade for universal thixotropic performance
- Direct equivalent to Aerosil 200 and CAB-O-SIL M-5 at competitive cost
- Excellent anti-sag in gelcoat, UPR hand lay-up, and epoxy coatings
- Rapid thixotropy recovery after shear — prevents sag within seconds of application
- Manufactured by Shanghai Semitech New Material Co., Ltd. under strict quality control
SEMISIL 200 is Shanghai Semitech New Material Co., Ltd.'s most versatile hydrophilic fumed silica, with a BET surface area of 200 m²/g. This grade represents the ideal balance between thixotropic efficiency, ease of incorporation, and cost-effectiveness, making it the industry standard choice for a broad range of composite applications.
With a surface area of 200 m²/g, SEMISIL 200 offers more silanol groups per gram than SEMISIL 150, building stronger hydrogen-bonded networks in polar and semi-polar media at equivalent dosage. This results in higher thixotropic indices (TI 3–6 at 0.5–1.5 phr in UPR) suitable for hand lay-up, gelcoat, and filled compound applications. Under high shear, the network breaks down readily, allowing easy application by brush, roller, or spray, then rebuilds rapidly at rest to prevent drip and sag.
SEMISIL 200 performs excellently in gelcoat formulations, providing the anti-sag, sag-free vertical surface finish critical for high-quality boat hulls and bathroom products. It also improves the storage stability of filled polyester compounds, preventing heavy filler settling during storage. As a direct equivalent to Evonik Aerosil 200 and Cabot CAB-O-SIL M-5, SEMISIL 200 provides a cost-competitive, locally-sourced alternative for Chinese and Asian composite manufacturers without compromising performance.
Specifications
| Parameter | Value |
|---|---|
| Particle type | Hydrophilic (untreated) |
| DBP absorption | ~2.5 mL/g |
| SiO₂ content | ≥ 99.8% |
| Tapped density | ≤ 50 g/L |
| BET surface area | 200 ± 25 m²/g |
| Primary particle size | 7–15 nm |
| Loss on ignition (1000°C) | ≤ 1.0% |
| pH (4% in water/ethanol 1:1) | 3.6–4.3 |
| Moisture content (105°C, 2h) | ≤ 1.5% |
Applications
FAQ
In a typical isophthalic gelcoat (viscosity 800–1200 mPa·s), SEMISIL 200 at 0.5 phr achieves TI ~2.5–3.0; at 1.0 phr, TI ~4.0–5.0; at 1.5 phr, TI ~5.5–7.0. TI is measured as the ratio of viscosity at 1 RPM to viscosity at 10 RPM (Brookfield). Values of TI 4–6 are typical for good brush and spray application. Adjust dosage based on desired application method.
Direct Contact
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