ASTM_D_2024_-_09.pdf

Designation:D202409Standard Test Method forCloud Point of Nonionic Surfactants1This standard is issued under the fixed designation D2024;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1.Scope1.1 This test method covers a procedure to determine the“cloud point”of nonionic surfactants or detergent systems.Cloud Point is the temperature at which dissolved components(solids or liquids)are no longer completely soluble,precipatingas a second phase giving the fluid a cloudy appearance.It islimited to those surfactants and detergent systems for which thevisible solubility change occurs over a range of 1C or less atconcentrations of 0.5 to 1.0%in DI water between 30 and95C.1.2 Chemical LimitationsNonionic surfactants that exhibita characteristic cloud point in general terms consist of awater-in-soluble moiety condensed with 50 to 75%by weightof ethylene oxide.If the level of ethoxylation is too low thesurfactant may not be water soluble at temperatures less than30C,and if it is too high no cloud point may exist.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2E1 Specification for ASTM Liquid-in-Glass Thermometers3.Significance and Use3.1 The cloud point temperature is a reproducible charac-teristic of certain pure nonionic surfactants.It is also charac-teristic of certain nonionic surfactant formulated systems.Thistest method is appropriate for both systems.NOTE1If the transition from a distinctly cloudy to a clear solution isnot sharp,that is,if it does not take place within a range of 1C,this testmethod is not appropriate.4.Interferences4.1 Ionic surfactants or detergents in concentrations down to1%or less of the nonionic surfactant drastically raise thecharacteristic cloud point of the latter.The presence of salts andbases(that is,non-surface active materials)will lower thecharacteristic cloud point,while acids tend to raise the cloudpoint.5.Apparatus5.1 ThermometerAn ASTM Partial Immersion Thermom-eter having a range from 20 to+150C or 0 to 302F andconforming to the requirements for Thermometer 1C or 1F inaccordance with Specification E1.6.Procedure6.1 Prepare a 1.0%test solution by weighing a 1 6 0.1-gsample into a 150-mL beaker and add 99 g of distilled orde-mineralized water which is at a temperature of less than30C,i.e.room temperature.Mix until the sample is dissolved;initial sample should be clear and homogeneous.Pour 50 6 2mL of test solution into a 25 by 200-mm borosilicate glass testtube.Place the filled test tube into a 1000 mLbeaker water bathcontaining 900 mL of water and a magnetic stirrer.Position thetube on an angle so it rests in the pour point of the beaker.Insert a thermometer into the test tube and in the water bath tomonitor temperatures.Slowly heat water bath and sample at arate of about 2-4C per minute while gently stirring with thestir bar.As the sample temperature starts to increase,use thethermometer to gently agitate the test solution to keep ituniform and until the test solution becomes definitely cloudy.Carefully remove sample tube from heat.Note;if temperatureis above 40C a protective glove may be needed to lift the hottube.While stirring slowly with the thermometer,allow the testsolution to cool slowly until it becomes clear.Record this cloudpoint temperature(Note 1).7.Precision7.1 The following precision data provide a reasonable basisfor judging the significance of the results:1This test method is under the jurisdiction of ASTM Committee D12 on Soapsand Other Detergentsand is the direct responsibility of Subcommittee D12.15 onPhysical Testing.Current edition approved Oct.1,2009.Published November 2009.Originallyapproved in 1962 as D2024 62 T.Last previous edition approved in 2003 asD2024 65(2003).DOI:10.1520/D2024-09.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 7.1.1 RepeatabilityDuplicate results by the same operatorshould not be considered suspect unless they differ by morethan 0.5C.7.1.2 ReproducibilityThe average result reported by onelaboratory should not be considered suspect unless it differsfrom that of another laboratory by more than 1.0C.ASTM International takes no position respecting th