The results of this test provide a relative measure of the total soluble fraction of polypropylene homopolymers and copolymers. The soluble fraction approximately correlates to the amorphous fraction in the polypropylene. Xylene is widely used for determining the soluble fraction in polypropylene as it is more specific to the atactic fraction than other solvents. The concentration of a soluble fraction obtained with a specific solvent has been found to relate closely to the performance characteristics of a product in certain applications, for example film and fiber. Data obtained by one solvent and at one precipitation time cannot be compared with data obtained by another solvent or precipitation time, respectively.

1.1 This test method is to be used for determining the 25°C xylene-soluble fraction of polypropylene homopolymers and copolymers.

1.2 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.

Note 1—This test method is technically equivalent to ISO 16152.