ASTM D2024-65(2003) (R1965)

1.1 This test method covers the determination of the solubility inversion temperature or "cloud point" of nonionic surfactants or detergent systems which are characteristically less soluble in water at higher temperatures than at lower temperatures. It is limited to those surfactants and detergent systems for which the visible solubility change occurs over a range of 1°C or less at concentrations of 0.5 to 1.0 % in water between 30 and 95°C.

1.2 Chemical LimitationsNonionic surfactants that exhibit a characteristic cloud point in general terms consist of a water-in-soluble moiety condensed with 50 to 75 % by weight of ethylene oxide.

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 and health practices and determine the applicability of regulatory limitations prior to use.

The cloud point temperature is a reproducible characteristic of certain pure nonionic surfactants. It is also characteristic of certain nonionic surfactant formulated systems. This test method is appropriate for both systems.

Note 1—If the transition from a distinctly cloudy to a clear solution is not sharp, that is, if it does not take place within a range of 1°C, this test method is not appropriate.