What is elongation at break and elongation at break?
The elongation at break or elongation at break is a measure of the deformability of a material until it tears. It describes the percentage by which a material - such as rubber, plastic or metal - can stretch in length under tensile load before it breaks. In rubber and elastomer technology, it is a key parameter for assessing elasticity, flexibility and ductility. It depends on the polymer structure, the cross-linking density, the temperature and the Ageing of the material. Plasticiser, Fillers and Crosslinking chemicals can specifically increase or decrease the value. Ageing influences such as ozone or UV radiation often significantly reduce the elongation at break due to material embrittlement.
- Natural rubber (NR): > 500 %
- Silicone rubber (VMQ): 300-700 %
- EPDM, TPE, PUdepending on the mixture 100-500 %
How is elongation at break measured?
The elongation at break is determined in a tensile test in accordance with the standard. A standardised sample is continuously stretched until it breaks. The relative change in length compared to the original length is measured as a percentage:
A (%) = ((l_break - l_0) / l_0) × 100
Example:
- Initial length: 50 mm
- Breaking length: 200 mm
The resulting elongation at break is 300 %