ASTM D3900-17(2021)

4.1These test methods can be used for determining which EPDM polymers are evaluated in the different compounds in Test Methods D3568.

4.2Differences in ethylene sequence distribution cause differences in crystallinity and green strength at the same ethylene content. Since these are important variables in EPM and EPDM processability and end-use properties, the ethylene content of the rubber should not be used as the sole measurement to determine the suitability of a particular rubber for an intended purpose.

1.1These test methods cover the determination of the proportion of ethylene and propylene units in ethylene-propylene copolymers (EPM) and ethylene-propylenediene terpolymers (EPDM) over the range from 35 to 85 mass % ethylene. Four test methods are needed to encompass the variety of commercial polymers that contain additives or polymerized diene units that interfere with the various infrared peaks. Except when interferences are present, all four test methods should give similar results. The test methods appear in the following order:

1.2These test methods are not applicable to oil-extended EPDM unless the oil is first removed in accordance with Test Method D.

1.3The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.4This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.5This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.