Expanded PTFE (ePTFE) exhibits a unique combination of physical properties that make it valuable for sealing, filtration, and insulation applications. Its key characteristics include exceptional sealability (0.0 ml/hr leakage for ASTM Fuel A), high compressibility (68%) with moderate recovery (12%), and temperature-dependent creep relaxation (32% at 212°F). The material shows excellent chemical resistance with a V0 flammability rating, 95% limiting oxygen index, and minimal water absorption (0.01%). Mechanical properties vary by form, with tensile strength ranging from 1,600 psi in thin sheets to 6,240 psi in denser variants, alongside a low coefficient of friction and Shore D hardness of 60-65. Its density (2.2 g/cm³) and UV resistance contribute to durability in harsh environments.
Key Points Explained:
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Sealability Performance
- Demonstrates near-perfect fluid sealing with 0.0 ml/hr leakage for ASTM Fuel A and 0.16 ml/hr for nitrogen
- Achieved through its microporous structure that blocks liquid penetration while allowing controlled gas permeability
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Mechanical Flexibility
- Compressibility (68%): Enables tight sealing under compression without permanent deformation
- Recovery (12%): Partial rebound after compression maintains seal integrity
- Creep Relaxation: Varies with temperature (32% at 212°F vs. 16% at 73°F), critical for high-temperature applications
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Flame & Chemical Resistance
- V0 flammability rating: Self-extinguishing properties
- 95% limiting oxygen index: Requires near-pure oxygen to combust
- 0.01% water absorption: Hydrophobicity prevents swelling in wet environments
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Structural Durability
- Tensile strength: Ranges from 1,600 psi (thin sheets) to 6,240 psi (dense forms)
- Hardness: 60-65 Shore D balances flexibility and load-bearing capacity
- Density (2.2 g/cm³): Lightweight yet structurally stable
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Environmental Stability
- UV resistance: Maintains properties in sunlight-exposed applications
- Temperature tolerance: Withstands autoclaving (typically 121°C/250°F)
- Radiation vulnerability: Poor resistance to gamma/X-rays limits nuclear applications
These properties collectively make ePTFE ideal for gaskets, medical implants, and industrial seals where chemical inertness, thermal stability, and mechanical resilience are paramount. The material's opacity (refractive index 1.38) and low friction coefficient further expand its use in optical and moving-part applications.
Summary Table:
| Property | Value/Range | Key Benefit |
|---|---|---|
| Sealability | 0.0 ml/hr (ASTM Fuel A) | Near-perfect fluid sealing, ideal for gaskets and industrial seals |
| Compressibility | 68% | Ensures tight sealing under compression without permanent deformation |
| Recovery | 12% | Maintains seal integrity after compression |
| Flame Resistance | V0 rating, 95% LOI | Self-extinguishing, suitable for high-oxygen environments |
| Water Absorption | 0.01% | Hydrophobic, prevents swelling in wet conditions |
| Tensile Strength | 1,600–6,240 psi | Durable yet flexible, adaptable to thin sheets or dense forms |
| UV/Temperature Stability | Resistant up to 250°F | Withstands autoclaving and sunlight exposure |
Upgrade your sealing solutions with KINTEK’s precision-engineered ePTFE components! Whether you need custom gaskets, medical-grade liners, or industrial seals, our expanded PTFE products deliver unmatched chemical resistance, thermal stability, and mechanical resilience. Contact our team today to discuss prototyping or high-volume orders tailored to your industry—semiconductor, medical, lab, or beyond. Let’s engineer reliability together!