ASTM Rubber Testing Methods Explained

Testing Capabilities

ODR, (D2084)

The D2084 test method is used to determine the vulcanization characteristics of (vulcanizable) rubber compounds.

This test method may be used for quality control in rubber manufacturing processes, for research and development testing of raw-rubber compounded in an evaluation formulation, and for evaluating various raw materials used in preparing (vulcanizable) rubber compounds.

Mooney Scorch, (D1646)

The Mooney Scorch (D1646) test measures the viscosity and pre-vulcanization characteristics of rubber.

Viscosity—Viscosity values determined by this test method depend on molecular structure, molecular weight, and non-rubber constituents that may be present.

Pre-Vulcanization Characteristics—The onset of vulcanization can be detected with the Mooney viscometer as evidenced by an increase in viscosity.

Tensile/Elongation, (D412)

The Tensile/Elongation (D412) test methods cover procedures used to evaluate the tensile (tension) properties of vulcanized thermoset rubbers and thermoplastic elastomers.

Hardness, (D2240)

The ASTM Hardness, (D2240) test is based on the penetration of a specific type of indentor when forced into the material under specified conditions. The indentation hardness is inversely related to the penetration and is dependent on the elastic modulus and viscoelastic behavior of the material. The geometry of the indentor and the applied force influence the measurements such that no simple relationship exists between the measurements obtained with one type of durometer and those obtained with another type of durometer or other instruments used for measuring hardness. This test method is an empirical test intended primarily for control purposes. No simple relationship exists between indentation hardness determined by this test method and any fundamental property of the material tested.

Specific Gravity, (D471)

The Specific Gravity (D471) method covers the required procedures to evaluate the comparative ability of rubber and rubber-like compositions to withstand the effect of liquids. It is designed for testing: (1) specimens of vulcanized rubber cut from standard sheets, (2) specimens cut from fabric coated with vulcanized rubber, or (3) finished articles of commerce.

Compression Set, (D395)

Compression set tests are intended to measure the ability of rubber compounds to retain elastic properties after prolonged action of compressive stresses. The actual stressing service may involve the maintenance of a definite deflection, the constant application of a known force, or the rapidly repeated deformation and recovery resulting from intermittent compressive forces. Though the latter dynamic stressing, like the others, produces compression set, its effects as a whole are simulated more closely by compression flexing or hysteresis tests. Therefore, compression set tests are considered to be mainly applicable to service conditions involving static stresses. Tests are frequently conducted at elevated temperatures.

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