ASTM D4559-99(2018)

4.1 High values may indicate contamination of the silicone with other materials, inadequate removal of volatile components by the producer, or the presence of a depolymerization catalyst.

4.2 The outcome will be affected directly by the presence of any high vapor pressure material in the sample, such as solvents or low molecular weight silicones.

4.3 A high volatile content could also indicate the presence of a depolymerization catalyst in the fluid. The time and temperature specified in this test method are ideal for detecting the effect of such a material, as the depolymerization takes place at a highly accelerated rate and the low molecular weight components are rapidly evaporated. The result is a very significant weight loss during the test period. The exact amount depends on the type and amount of catalyst present. The conditions specified in the method should not cause measureable depolymerization of silicone if such a catalyst is not present.

1.1 This test method describes a procedure for determining the volatile matter in silicone fluids used for electrical insulation.

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

1.4 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.