ASTM_D_2578_-_17.pdf

Designation:D257817Standard Test Method forWetting Tension of Polyethylene and Polypropylene Films1This standard is issued under the fixed designation D2578;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.1.Scope*1.1 This test method covers the measurement of the wettingtension of a polyethylene or polypropylene film surface incontact with drops of specific test solutions in the presence ofair.1.2 The values stated in SI units are to be regarded asstandard.The values given in parentheses are mathematicalconversions to inch-pound units that are provided for informa-tion only and are not considered standard.NOTE1This test method and the specified reagents were specificallydeveloped for polyethylene and polypropylene films.It is possible toutilize this test method and the specified reagents for films composed ofother polymers,but this can affect the surface energies of the gas-liquidand solid-liquid interfaces,which will affect the contact angle and wettingtension.The applicability and significance for use of non-polyolefinmaterials must be established by the user.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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.Specific hazards statements are given in Section 8.NOTE2This test method is equivalent to ISO 8296.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D618 Practice for Conditioning Plastics for TestingE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2 ISO Standard:ISO 8296 PlasticsFilm and SheetingDetermination ofWetting Tension33.Summary of Test Method3.1 In this test method drops of a series of mixtures offormamide and ethyl Cellosolve4of gradually increasing sur-face tension are applied to the surface of the polyethylene orpolypropylene film until a mixture is found that just wets thefilm surface.The wetting tension of the polyethylene orpolypropylene film surface will be approximated by the surfacetension of this particular mixture.4.Significance and Use4.1 When a drop of liquid rests on the surface of a solid,anda gas is in contact with both,the forces acting at the interfacesmust balance.These forces can be represented by surfaceenergies acting in the direction of the surfaces and it followsthat:GLcos 5 GS2 SL(1)where:=angle of contact of the edge of the drop with the solidsurface,GL=surface energy of the gas-liquid interface,GS=surface energy of the gas-solid interface,andSL=surface energy of the solid-liquid interface.4.1.1 The right side of the above equation(the differencebetween the surface energies of the gas-solid and solid-liq-uid interfaces)is defined as the wetting tension of the solidsurface.It is not a fundamental property of the surface butdepends on interaction between the solid and a particularenvironment.4.1.2 When the gas is air saturated with vapors of the liquid,GL will be the surface tension of the liquid.If the angle ofcontact is 0 the liquid is said to just wet the surface of the1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.19 on Film,Sheeting,andMolded Products.Current edition approved Dec.15,2017.Published January 2018.Originallyapproved in 1967.Last previous edition approved in 2009 as D2578-09.DOI:10.1520/D2578-17.2For 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.3Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.4Registered trademark of Union Carbide Corp.for ethylene glycol monoethylether.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1 solid,and in this particular case(