To measure the strength of rubber and vulcanized rubber products, a variety of testing methods are employed. These methods seek to understand the material's resistance to different types of stress, such as tensile, compressive, and shear forces. Common testing techniques include:

• Tensile testing: This involves applying a tensile force to a rubber specimen until it fractures. The resulting data provides information about the material's tensile strength, elongation at break, and modulus of elasticity.
• Compression testing: This method assesses the ability of a rubber sample to withstand crushing loads. Results show the compressive strength, yield point, and deformation characteristics of the material.
• Shear testing: This test measures the resistance of rubber to sliding. It is particularly relevant for applications involving friction and wear, such as gaskets and seals.

In addition to these fundamental tests, other methods, like dynamic testing and fatigue testing, are often employed to characterize the behavior of rubber under more complex loading conditions. By employing a combination of testing techniques, engineers can gain a comprehensive understanding of the strength properties of rubber materials and ensure their suitability for specific applications.

General Requirements for Test Methods on Rubber and Vulcanized Rubber Materials

When establishing test methods for rubber and vulcanized rubber materials, numerous general requirements must be achieved to ensure valid and comparable results. These needs aim to outline standardized procedures that reflect the characteristics of rubber materials precisely.

A key requirement is the determination of appropriate test methods that are adequately related to the intended properties being evaluated. This demands a thorough understanding of the properties of rubber and the elements that can influence test results. ,Moreover, test methods should be simple to perform and yield clear and meaningful data.

• Consideration must be given to the repeatability of test methods, ensuring that equivalent materials generate consistent results when tested under the same conditions.
• Test methods should be specified in a clear and brief manner, including all essential parameters and procedures.

Determination of Tensile Properties of Vulcanized Rubber

Vulcanized rubber materials possess a wide range of mechanical properties that are vital for diverse applications. The tensile properties of vulcanized rubber, including ultimate tensile strength, strain at rupture, and rigidity, are heavily influenced by various factors such as the type of rubber blend, the amount of sulfur crosslinking agent, and the curing temperature. Diligently determining these properties is essential for ensuring the performance and durability of rubber products.

A series of standardized tests are conducted to evaluate the tensile properties of vulcanized rubber samples. These tests typically involve applying a controlled tensile force on a specimen until failure occurs. The data obtained from these tests are then interpreted to quantify the various mechanical properties.

Grasping the factors that influence the tensile properties of vulcanized rubber is essential for improving the performance and durability of rubber products.

Determination of Tear Resistance of Vulcanized Rubber

Tear resistance is a crucial property for vulcanized rubber components subjected to tensile stresses. It quantifies the rubber's ability to resist tearing or splitting when subjected to an applied force. To determine tear resistance, a standardized test method is employed, typically involving a double-point tearing apparatus. The test specimen, prepared according to specific dimensions and conditions, is held in the apparatus and a defined load is applied constantly. The force required to propagate a tear through the rubber sample is measured and recorded as the tear strength.

• Factors influencing tear resistance include:
• polymer type, filler content, crosslink density
• Sample configuration
• Ambient temperature and humidity

Understanding tear resistance is crucial for designing rubber products that can withstand the demands of their intended applications.

Test Method for Hardness of Vulcanized Rubber

The resistance of vulcanized rubber needs to be assessed using a variety of methods. A common method employs the Rockwell instrument, which measures the depth of indentation caused by a specific weight. The higher the indentation, the flexible the rubber. Results are expressed in units of Shore A hardness points, which provide a standardized measure of the rubber's hardness.

Other methods for determining rubber hardness include the Barcol test, which quantifies the force required to indent the rubber with a specific indenter. The choice of technique depends factors such as the nature of rubber being tested and the intended application.

Testing Procedure for Compression Set of Vulcanized Rubber

Evaluating the deformation under load of vulcanized rubber is a crucial step in determining its suitability for various applications. This test protocol involves subjecting a specimen of vulcanized rubber to a specified compressive force for a specific period.

After the holding period, the specimen is discharged from the compression, and the amount of permanent set is measured. This value provides an indication of the rubber's resistance to deformation under stress.

• Factors influencing the compression set include rubber composition, vulcanization temperature, and loading conditions.
• The test is typically conducted at elevated temperatures to simulate real-world applications.

A lower compression GB/T 14370 set value generally indicates a more resilient rubber. The procedure adheres to standardized guidelines and standards to ensure accurate and reliable results.