ASTM D4937-96(2017)

5.1 This test method is designed to assess the relative purity of production PPDs. These additives are primarily used as antiozonants for tires and other rubber or polymeric products.

5.2 Since the results of this test method are based on area normalization, it assumes that all components are eluted from the column and each component has the same detector response. Although this is not strictly true, the errors introduced are relatively small and much the same for all samples; thus, they can be ignored since the intent of the test method is to establish relative purity.

5.3 Although trace amounts of “low boilers” are present in production samples, they are disguised by the solvent peak when using packed columns (Procedure A).

1.1 This test method covers the determination of the purity of Class I, II, and III p-phenylenediamine (PPD) antidegradants as described in Classification D4676 by gas chromatography (GC) detection and area normalization for data reduction.

1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

1.3 This 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 and health practices and determine the applicability of regulatory limitations prior to use.

1.4 This 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.