1、BRITISH STANDARD BS EN 14210:2003 Surface active agents Determination of interfacial tension of solutions of surface active agents by the stirrup or ring method The European Standard EN 14210:2003 has the status of a British Standard ICS 71.100.40 BS EN 14210:2003 This British Standard was published
2、 under the authority of the Standards Policy and Strategy Committee on 19 January 2004 BSI 19 January 2004 ISBN 0 580 43294 7 National foreword This British Standard is the official English language version of EN 14210:2003. The UK participation in its preparation was entrusted to Technical Committe
3、e CII/34, Methods of test for surface active agents, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this d
4、ocument may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the necessary provisions of a contra
5、ct. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for
6、 change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 13 and a back cover. The BSI copyright notice displayed in
7、this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date CommentsEUROPEANSTANDARD NORMEEUROPENNE EUROPISCHENORM EN14210 December2003 ICS71.100.40 Englishversion SurfaceactiveagentsDeterminationofinterfacialtensionof solutionsofsurfaceactiveagentsby
8、thestirruporringmethod AgentsdesurfaceDterminationdelatensioninterfaciale dessolutiondagentsdesurfaceparlamthodelanneau oultrier GrenzflchenaktiveStoffeBestimmungder GrenzflchenspannungvongrenzflchenaktivenLsungen mittelsBgeloderRingverfahren ThisEuropeanStandardwasapprovedbyCENon1October2003. CENme
9、mbersareboundtocomplywiththeCEN/CENELECInternalRegulationswhichstipulatetheconditionsforgivingthisEurope an Standardthestatusofanationalstandardwithoutanyalteration.Uptodatelistsandbibliographicalreferencesconcernings uchnational standardsmaybeobtainedonapplicationtotheManagementCentreortoanyCENmemb
10、er. ThisEuropeanStandardexistsinthreeofficialversions(English,French,German).Aversioninanyotherlanguagemadebytra nslation undertheresponsibilityofaCENmemberintoitsownlanguageandnotifiedtotheManagementCentrehasthesamestatusasthe official versions. CENmembersarethenationalstandardsbodiesofAustria,Belg
11、ium,CzechRepublic,Denmark,Finland,France,Germany,Greece, Hungary,Iceland,Ireland,Italy,Luxembourg,Malta,Netherlands,Norway,Portugal,Slovakia,Spain,Sweden,SwitzerlandandUn ited Kingdom. EUROPEANCOMMITTEEFORSTANDARDIZATION COMITEUROPENDENORMALISATION EUROPISCHESKOMITEEFRNORMUNG ManagementCentre:ruedeS
12、tassart,36B1050Brussels 2003CEN Allrightsofexploitationinanyformandbyanymeansreserved worldwideforCENnationalMembers. Ref.No.EN14210:2003EEN14210:2003(E) 2 Contents page Foreword3 1 Scope 4 2 Principle4 3 Apparatus .4 4 Preparationofapparatus 7 5 Procedure .7 6 Expressionofresults . .8 7 Precision.1
13、2 8 Testreport . .12 Bibliography 13EN14210:2003(E) 3 Foreword ThisdocumentEN14210:2003hasbeenpreparedbyTechnicalCommitteeCEN/TC276“Surfaceactiveagents”, thesecretariatofwhichisheldbyAFNOR. ThisEuropeanStandardshallbegiventhestatusofanationalstandard,eitherbypublicationofanidenticaltextor byendorsem
14、ent,atthelatestbyJune 2004,andconflictingnationalstandardsshallbewithdrawnatthelatestby June2004. ThisdocumentincludesaBibliography. AccordingtotheCEN/CENELECInternalRegulations,thenationalstandardsorganizationsofthefollowing countriesareboundtoimplementthisEuropeanStandard:Austria,Belgium,CzechRepu
15、blic,Denmark,Finland, France,Germany,Greece,Hungary,Iceland,Ireland,Italy,Luxembourg,Malta,Netherlands,Norway,Portugal, Slovakia,Spain,Sweden,SwitzerlandandtheUnitedKingdom.EN14210:2003(E) 4 1Scope ThisEuropeanStandardspecifiestestmethodsforthedeterminationofinterfacialtensionintherangefrom 4mN/mto5
16、0mN/mbetweentwoimmiscibleliquidswhichcanalsobefreefromsurfaceactiveagents. Itisparticularlysuitablefordeterminingtheinterfacialtensionbetweenwateroraqueoussolutionsandorganic liquidswhichareimmisciblewithwater. 2Principle Themaximumforce, F,necessarytopullortoforceastirruporringoflength, l,outofthei
17、nterfacebetweentwo liquidsinthedirectionofthenonaqueousphaseismeasured.Theinterfacialtension, ,isobtainedbycalculation wherethefollowingapproximateequation(1)servesasbase: l F 2 = g (1) 3Apparatus 3.1Tensiometer 3.1.1 General Thetensiometershallbedesignedforusewithastirruporringandshallconsistessent
18、iallyofthepartsspecified in3.1.2and3.1.3. 3.1.2 Dynamometer(e.g.torsionbalanceorinductiveforcetransducer),capableforreadingofftheforcetothe nearest0,1mN/movertheeffectivelengthofthestirruporring. 3.1.3 Supportforthemeasuringvessel ,consistingofahorizontalplatformwhichcanbemovedverticallyup anddown,e
19、.g.withtheaidofaprecisiondrive. 3.2Stirrup Thestirrupshallconsistofplatinum/iridiumwirewithatestwirediameterof0,1mmandalengthof20mm to40mm.Thelengthofthetwobranchesshallbeabout20mm.Twosmallplatinumballscanbeattachedtothe lowerendsofthebranchesascounterweightsor,alternatively,thelowerendsofthebranche
20、scanbejoinedbya platinumwire(seeFigure1asanexample).EN14210:2003(E) 5 Dimensionsinmillimetres Figure1Stirrupformeasuringinterfacialtension NOTE ThestirrupspecifiedinEN14370formeasuringthesurfacetensionisidenticalwiththatoneshowninFigure1, exceptforthelengthsofthemeasuringwireandthebranches. 3.3Ring
21、Theringshallconsistofaplatinumorplatinum/iridiumwirewithathicknesslessthanorequalto0,4mmanda meancircumferenceof60mm.Bymeansofawirestirrup,itshallbeattachedinahorizontalpositiontoametal rodformingthelinktothetensiometer(seeFigure2asanexample).EN14210:2003(E) 6 Dimensionsinmillimetres Key 1 Metalrod
22、2 Wireloop 3R i n g Figure2Ringformeasuringinterfacialtension NOTE TheringspecifiedinEN14370formeasuringthesurfacetensionisidenticalwiththatoneshowninFigure2. 3.4Sample vessel Thesamplevesselfortheliquidundertestshallbeaglassvesselwhichissuitableforuseinathermostat.Itshall haveasufficientcapacityfor
23、theliquidwhich,ifnecessary,shallbeprotectedfromevaporation.Itshallbe constructedsuchthatthetemperatureofthegasphaseabovetheliquidcanalsobekeptconstantbythermostat. Thereisnoneedtouseathermostatformeasurementatroomtemperature.Thesamplevesselshallconsistofa cylindricalglasscontainerwithaninternaldiame
24、terofatleast45mmforusewiththeringmethodorstirrup method. NOTE Ifavesseloflessthan45mmdiameterneedstobeused(forexample,ifonlysmallamountsofsampleare available),walleffectscancauseanerrorintheinterfacialtensionmeasurement.Themagnitudeofthiserrordependsonthe distancebetweenthewallofthevesselandtheedgeo
25、ftheringorstirrup.EN14210:2003(E) 7 4 Preparationofapparatus 4.1Cleaning Cleantheglassvesselscarefully,firstbythoroughpreliminarycleaningusingasuitablesolvent,forexample propan2olorpropanone.Thenrinsethemrepeatedlywithfreshlydoubledistilledwateranddrythem.Cleanand rinsethestirrupsorringsinthesameman
26、ner,andthenheatthembrieflytoincandescenceinamethanolor ethanolflame(thelattermaybepreferredsinceithasalowvapourpressureandhigherflashpoint),preferablya nonluminousnaturalgasflame,ensuringtheyareonlyheatedtoredheatandnevertowhiteheat. NOTE Shouldthestirrupsorringsbecomecontaminatedwithresidues,forexa
27、mplefromsiliconesorcationicsurface activeagents,itcanbepreferabletocleanwithasulfochromicacidmixtureorasspecifiedinISO6889. 4.2Measurement preparation Doubledistilledwaterorwaterofequivalentpurityshallbeusedtoprepareanyaqueoussolutionrequiredforthe test. Thetemperatureoftheliquidsshallbekeptconstant
28、tothenearest 0,5 Cduringthemeasurement.The measurementtemperaturechosenshallbeanappropriateonefortheobjectiveofaparticulartest.Measurementsat roomtemperaturepresentthefewestproblems. Theinterfacialtensionchangeswithtimeandcanbeaffectedbythechemicalnatureofasurfaceactiveagent,its concentration,whethe
29、ritisdissolvedintheupperorlowerphase,itsadsorptivecapacityanditsadsorptionrate duringthechange.Soitisnotpossibletospecifyanappropriatetimeforstartingthemeasurements.Therefore, severalmeasurementsoftheinterfacialtensionasafunctionoftimeand,consequently,oftheageoftheinterface shallbeperformed.Afterati
30、mewhichischaracteristicforeverysystem,nofurtherchangesareobservedinthe interfacialtensionsinceanequilibriumstateisestablished.Itisadvantageoustousecommerciallyavailable, automatictensiometerstocarryoutsuchmeasurements. Interfacialsystemsareextremelysensitivetocontaminants.Forthisreason,noworkinvolvi
31、ngvolatilesubstances shallbecarriedoutinthemeasurementroomandtheapparatusshallbeprotectedbyanenclosureofthetypeused forbalances.Thisprecautionalsofacilitatesmaintenanceofaconstanttemperature. 5Procedure 5.1General Twomethodsofmeasurementaredescribedin5.2and5.3.Intherelativestirruporringmethod(see5.2
32、),the measuredvalueiscomparedwiththecorrespondingvaluedeterminedonasystemoftwoliquidswithsimilar densitiestothoseoftheliquidsundertestdensitiesandknowninterfacialtension.Intheabsolutering method(5.3),accountistakenofafactorfortheapparatusdeterminedusinganadjustmentweightandaZuidema andWaterscorrecti
33、onfactor1whendeterminingtheinterfacialtension.TheZuidemaandWatersfactorisbased onthecorrectiondeterminedempiricallybyHarkinsandJordan2formeasurementsmadebytheringmethod. Differentmeasurementproceduresareadopted,dependingonwhetherthedensityoftheaqueousphaseisgreater orlessthanthatofthenonaqueousphase
34、. 5.2 Relativestirruporringmethod 5.2.1Method A Method Aisamethodforsystemsinwhichthedensityoftheaqueousphaseisgreaterthanthatofthe nonaqueousphase. Useapipettetotransferanamountoftheaqueousphaseabout15mmdeeptothemeasuringapparatusholding thetipofthepipetteagainstthevesselwall,avoidingbubbles.Checkt
35、hatthetestwireofthestirruporringis horizontalbyusingthesurfaceoftheliquidasamirrorwhenthestirruporringisjustaboveit.Thenslowlyraise theplatformandthemeasurementvesseluntilthestirruptestwireorringisimmersedintheaqueousphase.ThenEN14210:2003(E) 8 addaroughly15mmdeeplayerofthenonaqueousphase,againavoid
36、ingbubbles,andleaveforatleast5min (seeclause3)toallowtheliquidstobecomemutuallysaturated. Thenrepeatedlylowertheplatformandraiseitagainuntilthefilmalmostbreaks.Readoffthemaximumvalue, W 2 , obtainedonthetensiometereverytime.Readoffthevalue W 1 whenthestirruptestwireorringis immersedwithoutafilminthe
37、upperphasetothesameextentaswhenmeasuring W 2 .Thisgivesthedifference D W= W 2 W 1 .Ifthesameprocedureisusedforasystemoftwoliquidswithsimilardensitiesandknowninterfacial tension, 0 ,(e.g.avaluefromtheliterature), D W 0 isobtained. 5.2.2Method B MethodBisamethodforsystemsinwhichthedensityoftheaqueousp
38、haseislessthanthatofthenonaqueous phase. Pourboththephasesintothemeasurementvesseltoadepthof15mmineachcase,avoidingbubbles.After checkingthatthestirruporringishorizontal(asin5.2.1),raisetheplatformandmeasuringvesseluntilthestirrupor ringisimmersedintheupperphaseandleaveforatleast5min(seeclause4)toal
39、lowtheliquidstobecomemutually saturated.Thenraisetheplatformfurtheruntilthestirruporringpassesthroughtheinterfaceandafterthatraiseand loweritagainuntilthefilmalmostbreaks.Readoffthemaximumvalue, W 2 ,obtainedineachcase.Readoff W 1 when thestirrupmeasuringwireorringisimmersedwithoutafilminthelowerpha
40、setothesameextentasinthe measurementof W 2 .Thisyieldsthedifference D W= W 2 W 1 .Thendetermine D W 0 asin5.2.1. 5.3 Absoluteringmethod Calibratethetensiometerbyaddingaweightwithaknownmass, m,ofabout0,5gtotheringandregisterthe resultantreading, A 1 .Determinethemaximumvalue, W 2 ,fortheformationofth
41、efilmandthevalue, W 1 ,withoutafilm andtakethedifference, D W= W 2 W 1 ,asintherelativemethod(5.2.1or5.2.2). 6 Expressionofresults 6.1General Inviewofthemassofthestirruporringandofthefactthatthemagnitudeoftheforcesencounteredislow,itis advisabletoexpressallthequantitiesincentimetres,grams,seconds(cg
42、sunits),e.g. g=981cm/s 2 , ing/cm 3 andwirelengthandwirethicknessincentimetres.ThiswillgivetheinterfacialtensionintheSIunitmillinewtonsper meter(1mN/m=1dyn/cm). 6.2 Relativestirruporringmethod Therequiredinterfacialtension, g ,isgivenbyequation(2): o o W W g g = (2) where g o isthevaluegiveninthelit
43、eraturefortheinterfacialtensionofthereferencesystem; W W 0 see5.2.1or5.2.2.EN14210:2003(E) 9 6.3 Absoluteringmethod Determinethefactor, fortheapparatususingequation(3): 1 2 A A = (3) where D g m A p 2 2 = (4) where m isthemassoftheadditionalmass; g istheaccelerationduetogravity; D isthemeanringdiameter; A 1 isthereadingonthe
