Tensile Strength

The maximum stress (force per unit cross-sectional area) that a rubber specimen can sustain before breaking, expressed in megapascals (MPa) or psi. Measured per ASTM D412 (dumbbell or ring specimens pulled at 500 mm/min) or ISO 37. Tensile strength is a primary mechanical property used to characterize rubber compounds and assess quality. Typical values by elastomer type (with reinforcing carbon black): NR 25-32 MPa (highest of general rubbers due to strain crystallization), SBR 10-25 MPa, EPDM 10-20 MPa, NBR 10-25 MPa, neoprene CR 15-25 MPa, silicone VMQ 5-12 MPa (lowest), FKM 10-17 MPa, polyurethane PU 30-70 MPa (highest of all rubbers). Factors increasing tensile: higher carbon black loading (up to optimum), finer particle CB (N110 > N330 > N660), higher cross-link density (up to optimum), and strain-crystallizing polymers (NR). Tensile decreases with aging, heat exposure, and chemical attack. Per ASTM D412 and ISO 37. Tested at 23 ± 2°C. Often reported alongside elongation at break and modulus at 100/200/300% elongation. Minimum of 3 specimens averaged per ASTM D412.

What you need to know

The maximum stress (force per unit cross-sectional area) that a rubber specimen can sustain before breaking, expressed in megapascals (MPa) or psi.

Measured per ASTM D412 (dumbbell or ring specimens pulled at 500 mm/min) or ISO 37.

Tensile strength is a primary mechanical property used to characterize rubber compounds and assess quality.

Typical values by elastomer type (with reinforcing carbon black): NR 25-32 MPa (highest of general rubbers due to strain crystallization), SBR 10-25 MPa, EPDM 10-20 MPa, NBR 10-25 MPa, neoprene CR 15-25 MPa, silicone VMQ 5-12 MPa (lowest), FKM 10-17 MPa, polyurethane PU 30-70 MPa (highest of all rubbers).

Factors increasing tensile: higher carbon black loading (up to optimum), finer particle CB (N110 > N330 > N660), higher cross-link density (up to optimum), and strain-crystallizing polymers (NR).

Full definition

Tensile strength is a critical mechanical property of rubber materials, defined as the maximum stress that a rubber specimen can withstand before failure. This property is particularly significant in the evaluation of elastomers used in various applications, as it provides insight into their durability and performance characteristics. Tensile strength is quantified in megapascals (MPa) or pounds per square inch (psi), allowing for standardized comparisons across different materials. The measurement is conducted according to established protocols such as ASTM D412 or ISO 37, which utilize specific specimen shapes (like dumbbell or ring forms) and defined testing conditions (typically at a speed of 500 mm/min and a temperature of 23 ± 2°C). The resulting values not only reflect the intrinsic properties of the rubber compound but also indicate its suitability for specific applications.

Different types of elastomers exhibit varying tensile strength values, influenced by their chemical composition and structure. For instance, natural rubber (NR) shows the highest tensile strength among general rubbers, ranging from 25-32 MPa, due to its ability to undergo strain crystallization. In contrast, silicone rubber (VMQ) exhibits lower tensile strength, typically between 5-12 MPa, demonstrating the diversity in performance characteristics across elastomer types. Factors that can enhance tensile strength include higher carbon black loading (up to an optimum level), finer particle sizes of carbon black, and increased cross-link density, which collectively contribute to improved material resilience.

However, tensile strength is not a static property; it can decrease over time due to aging, exposure to heat, and chemical degradation. This makes regular testing and quality control essential in industries that rely on elastomers for critical applications. Moreover, tensile strength is often reported alongside other mechanical properties, such as elongation at break and modulus at specified elongation percentages (100%, 200%, and 300%). This comprehensive assessment provides a clearer picture of the rubber's performance under various conditions, making it a vital consideration in material selection and application design.

What you need to know

What you need to know: Tensile strength is the maximum stress a rubber can endure before breaking, measured in MPa or psi.

Typical tensile strength values: NR 25-32 MPa, SBR 10-25 MPa, EPDM 10-20 MPa, and neoprene 15-25 MPa.

Testing standards: Measured according to ASTM D412 or ISO 37, utilizing specific specimen shapes and conditions.

Factors affecting tensile strength: Higher carbon black loading, finer particle sizes, and increased cross-link density enhance the property.

Degradation risks: Tensile strength decreases with aging, heat exposure, and chemical attack, necessitating regular quality checks.

Industrial applications

1Used in automotive seals and gaskets where high tensile strength is critical for durability and performance.

2Applied in manufacturing high-performance tires that require resilience against mechanical stress.

3Utilized in the production of industrial hoses that need to withstand high pressure and tensile loads.

4Employed in the creation of vibration dampening components, where elasticity and tensile strength are crucial.

Common mistakes

✕Neglecting to account for environmental factors that can alter tensile strength over time.

✕Failing to adhere to testing standards, leading to inaccurate assessments of material properties.

✕Assuming all rubber types will perform similarly without considering their distinct tensile strength characteristics.

Tensile Strength

What you need to know

Full definition

What you need to know

Industrial applications

Common mistakes

Pro tip

Technical standards

Suppliers of industrial rubber in Mexico

Applicable standards