ASTM D7389-07(2019)

4.1 This test method is used to determine the free acid content of MAH-grafted waxes. The potential hydrolysis of the anhydride functionality of this wax in storage makes them unsuitable for determining free acid content by Test Method D1386. Free acid content is a significant quality control test, and is a determinant of the utility of the wax.

1.1 This test method covers the determination of the acid number of maleic anhydride (MAH) grafted waxes. The number is obtained by direct titration of the material and indicates the amount of free acid present.

1.2 This test method is applicable to MAH-grafted waxes because it uses a special sample preparation step (7.1) that is not required for other waxes. The special sample preparation reverses the hydrolysis of acid anhydride that can occur during storage of the wax.

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

1.4 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.5 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.