ASTM D1921

ASTM D1921 – Standard Test Methods for Particle Size (Sieve Analysis) of Plastic Materials

Description:

Significance and Use

4.1 These test methods are used to determine particle size distribution and therefore are useful for determining lot-to-lot uniformity.

4.2 The particle sizes of plastic materials affect the handling characteristics and sometimes will affect the processing characteristics of some polymers.

Scope

1.1 These test methods cover the measurement of the particle size of plastic materials in the powdered, granular, or pelleted forms in which they are commonly supplied. As these test methods utilize dry sieving, the lower limit of measurement is considered to be about 38 μm (No. 400 sieve). For smaller particle sizes, sedimentation test methods are recommended.

1.2 Two test methods are described:

1.2.1 Test Method A—This test method uses multiple sieves selected to span the particle size of the material. This method is used to determine the mean particle diameter and particle size distribution.

1.2.2 Test Method B—This test method is an abbreviated version of Test Method A conducted with a few specific sieves. This test method determines “percent passing” or “percent retained” on a given sieve. Test Method B is applicable to materials which do not have a normal particle size distribution such as pellets and cubes.

1.3 The values stated in SI units are to be regarded as standard for dimensions of the wire cloth openings and the diameter of the wires used in the wire cloth.