Moisture will affect the processability of some plastics. High moisture content causes surface imperfections (that is, splay or bubbling) or degradation by hydrolysis. Low moisture (with high temperature) causes polymerization.

The physical properties of some plastics are affected by the moisture content.

1.1 This method uses the reaction of Iodine (I₂) with water (Karl Fischer Reaction) to determine the amount of moisture in a polymer sample.

1.2 This test method is intended to be used for the determination of moisture in most plastics. Plastics containing volatile components such as residual monomers and plasticizers are capable of releasing components that will interfere with the I₂/water reaction.

1.3 This method is suitable for measuring moisture over the range of 0.005 to 100 %. Sample size shall be adjusted to obtain an accurate moisture measurement.

1.4 The values stated in SI units are regarded as the standard.

Note 1—This standard is technically equivalent to ISO 15512 Method B.

1.5 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.