The particle size distribution of powdered ion exchange resins and, more importantly, the derived parameters of mean particle size and percent above and below specified size limits are useful for determining batch to batch variations and, in some cases, can be related to certain aspects of product performance.

Although automatic multichannel particle size analyzers, of the type described in Section 9, yield information on the entire distribution of sizes present in a given sample, it has been found that, for this application, the numerical value of three derived parameters may adequately describe the particle size characteristics of the samples: the mean particle diameter (in micrometres), the percent of the sample that falls below some size limit, and the percent of the sample that falls above some size limit.

1.1 These test methods cover the determination of the physical and chemical properties of powdered ion exchange resins and are intended for use in testing new materials. The following test methods are included:

	Sections
Test Method A—Particle Size Distribution	5 to 15
Test Method B—Solids Content	16 to 23

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

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 consult and establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

5.1 This test method covers the instrumental determination of the particle-size distribution of powdered ion exchange resins.