KEVLAR® (Para aramids)
Para aramids -such as Kevlar®- are known for their incredible high strength and excellent heat/flame resistance. The high degree of crystallinity of the fibers is the main physical characteristic that transfers this excellent strength before breakage.
Meta-Aramid (Nomex®)
Meta aramids are a variety of polyamide that have outstanding heat/flame resistance. They possess excellent abrasion resistance and resistance towards chemical degradation.
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Meta-Aramid
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Standard Tenacity Para-Aramid
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High Modulus Para-Aramid
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Typical filament size (dpf)
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2
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1.5
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1.5
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Specific Gravity (g/cm3)
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1.38
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1.44
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1.44
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Tenacity (gpd)
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4-5
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20-25
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22-26
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Initial Modulus (g/dn)
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80-140
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500-750
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800-1000
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Elongation @ Break (%)
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15-30
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3-5
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2-4
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Continuous Operating
Temperature (F)
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400
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375
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375
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Decomposition
Temperature (F)
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750
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800-900
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800-900
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product description
Unlike other materials and fibers, that may require coatings and finishes to enhance their heat and /or flame protection, Kevlar® and Nomex® fibers are inherently flame-resistant and will not melt, drip, or support combustion. In other words, the thermal protection offered by Kevlar® and Nomex® is permanent — its superior flame resistance cannot be washed out or worn away. Materials that must be treated, in order to improve their fire-resisting performance (and whose protection may wane with wash and wear exposure) are known as “fire retardant.” Those with the superior inherent and permanent protection (i.e., Kevlar®, Nomex®, etc.) are referred to as “fire resistant.”
This superior heat and flame-resisting ability allows these fibers – and the textiles produced from them – to meet many industry standards industry standards that other materials cannot.
Both fibers are utilized (independently and in combination) for a wide array of products in fields such as:
- Firefighting
- Defense
- Forging and Smelting
- Welding
- Electrical and Utility
- Mining
- Racing
- Aerospace and Outer space
- Refining and Chemical
- And many others
As with all performance high-performing fibers, both Nomex® and Kevlar® have their weaknesses and limitations. For example, both will eventually degrade in performance and in color, with prolonged expose to UV light. Additionally, as porous materials, they will absorb water/moisture, and will gain weight as they take on water. Therefore, when evaluating a fiber(s) for a specific application, it is always crucial to take into consideration all potential actions, environments, and duration to which the end product will be exposed.