What is the difference between tensile strength and elongation at break in fibers?
- Sep 29
- 3 min read
Updated: Sep 30
When evaluating the performance of fibers, there are two physical properties that are most frequently mentioned.
They are tensile strength and elongation at break.
Although these two may seem similar, they actually represent different characteristics and serve as important criteria when selecting fibers.
In particular, polyester fiber demonstrates a well-balanced performance in both tensile strength and elongation, making it widely used across various industries and everyday applications.
In this post, we will take a closer look at tensile strength and elongation at break.
What is tensile strength?
Tensile strength is an indicator of how much force a fiber can withstand without breaking.
Units such as g/den, MPa, and N/5cm are commonly used, and the higher the value, the stronger and more durable the fiber is.
For example, polyester fiber has a higher tensile strength than cotton, allowing it to withstand greater loads under the same conditions. This makes it suitable for applications requiring high durability, such as carpets, filling materials, industrial fabrics, and ropes.
What is elongation at break?
Elongation at break refers to how much a fiber can stretch before it breaks, expressed as a percentage (%).
For example, if the elongation at break is 50%, it means that a fiber with an original length of 1 meter can stretch to 1.5 meters before breaking.
The higher the elongation, the more flexible and stretchable the fiber is; the lower the elongation, the stiffer and more prone to tearing it becomes.
Nylon, for instance, has a higher elongation at break than polyester, making it suitable for products that require elasticity, such as stockings and swimsuits. Cotton, on the other hand, has a lower elongation, meaning it does not stretch easily.
Comparison of Tensile Strength & Elongation at Break by Material
Material | Tensile Strength | Elongation at Break | Characteristics |
Polyester | High | Medium (40–60%) | Excellent strength and durability, suitable for various applications |
Nylon | High | Very High (≥60%) | Excellent elasticity and recovery, suitable for sports and leisure clothing |
Cotton | Low | Low (~10%) | Soft, but weak in strength and elasticity |
Wool | Medium | Medium (~25–35%) | Excellent insulation, but sensitive to moisture |
Why is the difference between tensile strength and elongation at break important?
The two indicators are complementary to each other.
When tensile strength is high, the product is strong but may become excessively stiff.
When elongation is high, the fiber is flexible and comfortable to wear, but long-term creep (permanent stretching) may occur.
Therefore, it is important to maintain a balance suitable for the intended application. Polyester fibers, with their high tensile strength and stable elongation in the 40–60% range, are ideal for uses that require both strength and flexibility.
At DK FIBER, we supply Grade “A” solid fibers used for nonwoven geotextiles in civil engineering.
The technical specifications of Grade “A” are as follows, and for more detailed information, please contact us directly.
ITEMS | SPEC. | RESULTS |
Solvent extract matter (% of OIL) | 0.20 ± 0.05 % | 0.15 % |
Fineness (Microscopic method) | 6 ± 1.0 Denier | 6.50 Denier |
Elongation | 70 ± 10 % | 65.00 % |
Fiber length | 51 ± 1.00 mm | 52.00 mm |
Crimp number | 8 ± 1.0 Pc/25mm | 9.00 |
Tensile Strength | – | 2.50 g/den |
Quality | GRADE “A” / Raw White color | Raw White color |
If you’d like to check out fibers for nonwoven geotextiles for civil engineering, get more information from the link below!
