1、Designation:D749013Standard Test Method forMeasurement of the Surface Tension of Solid Coatings,Substrates and Pigments using Contact AngleMeasurements1This standard is issued under the fixed designation D7490;the number immediately following the designation indicates the year oforiginal adoption or
2、,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 describes a procedure for the measure-ment of contact angles of two
3、liquids,one polar and the othernonpolar,of known surface tension on a substrate,pigment(inthe form of a disk),or cured or air dried coating in order tocalculate the surface properties(surface tension and its disper-sion and polar components)of the solid.1.2 The total solid surface tension range that
4、 can be deter-mined using this method is approximately 20 to 60 dyn/cm.1.3 The values stated in CGS units(dyn/cm)are to beregarded as standard.No other units of measurement areincluded in this standard.1.4 This standard does not purport to address all of thesafety concerns,if any,associated with its
5、 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:2D1193 Specification for Reagent WaterD5725 Test Method for Surface Wettabi
6、lity and Absorbencyof Sheeted Materials Using an Automated Contact AngleTester(Withdrawn 2010)3D7334 Practice for Surface Wettability of Coatings,Sub-strates and Pigments by Advancing Contact Angle Mea-surement3.Terminology3.1 Definitions:3.1.1 contact angle,nthe interior angle that a drop makesbetw
7、een the substrate and a tangent drawn at the intersectionbetween the drop and the substrate as shown in Fig.1;this isthe angle formed by a liquid at the three phase boundary wherea liquid,gas(air)and solid intersect.3.1.2 dispersion component,nthe component of solidsurface tension that is related to
8、 intermolecular attractioncaused by nonpolar dispersion forces.3.1.3 polar component,nthe component of solid surfacetension that is related to polar forces,such as hydrogenbonding and ion-dipole forces.3.1.4 solid surface tension,nthe surface tension of a solidsurface;this parameter cannot be measur
9、ed directly,but mustbe determined by extrapolation of polymer melt or solutiondata to 100%solids or by contact angles with liquids of knownsurface tension.3.1.5 surface energy,nexcess free energy of surfacemolecules compared to those of the bulk material;arises fromunbalanced molecular cohesive forc
10、es at a surface that causethe surface to contract and behave like a film or membrane(units are energy/unit areas such as joules/cm2).3.1.6 surface tension,nthe force necessary to break thesurface of a film of a given length(units are force/length,suchas dyn/cm or newtons/m);the same numerically as s
11、urfaceenergy,but different units.4.Summary of Test Method4.1 Contact angles of drops of distilled water and di-iodomethane(methylene iodide)are measured on the surfaceof interest.The two values are then substituted into twoseparate expressions of the Owens-Wendt-Kaelble equation(one for each liquid)
12、.This results in two equations in twounknowns,which are then solved for the dispersion and polarcomponents of surface tension.The sum of the components isthe surface tension of the solid.1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings,Materials,and Appl
13、ications and is the direct responsibility ofSubcommittee D01.23 on Physical Properties of Applied Paint Films.Current edition approved July 1,2013.Published August 2013.Originallyapproved in 2008.Last previous edition approved in 2008 as D7394 08.DOI:10.1520/D7490-13.2For referenced ASTM standards,v
14、isit 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.3The last approved version of this historical standard is referenced onwww.astm.org.*A Summary of
15、Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 5.Significance and Use5.1 The method described in this standard is based on theconcept that the total free energy at a surface is the sum o
16、fcontributions from different intermolecular forces,such asdispersion,polar and hydrogen bonding.There are othertechniques that employ three components(dispersion,polarand hydrogen bonding).These methods are further compli-cated by needing three to five test liquids and are not practicalfor routine testing.This method uses contact angles of twoliquids to provide data for the calculation of two components,dispersion,sd,and polar,sp.5.2 Dispersion and polar component data,along with thetotal solid