Natural-Latex天然胶乳-胶乳英文ppt-橡胶课件.ppt

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1、NaturalLatexControlandIndustrialProceduresEmilyLiuMaterialScienceNaturalLatexA.IntroductionB.ControlProceduresIntroductionCentrifugedlatexisprocessedintofinalarticlesbydipping,extruding,andcoating.Differentarticleshavedifferentphysicalandchemicalrequirements,whichmeansthatthelatexusedintheirmanufac

2、turemustbemodifiedbytheadditionofagreatvarietyofsubstancesthatgiveeach"formulation"itsuniquecharacteristics.Thesecharacteristicsarewell-specifiedandmustbecarefullycontrolled.ExampleofaControlSheetforLATZLatexAnexampleofacontrolsheetforthetypeofnaturalrubberlatexthatiscommonlyusedinmakingsurgicalglo

3、vesisgivenintheTable1.ThepurposeofthisPPT：Weexplainbrieflyhowsomeofthesecharacteristicsarecontrolled.ControlProcedures3456DryRubberContent(DRC)SurfaceTensionpHMeasurementMechanicalStabilityKOHNumberTotalSolidContent(TSC)Viscosity271ControlProcedures1.DeterminationoftheTotalSolidContent(TSC)ofLatexA

4、ddyourtitleinhereTheTSCoflatexisobtainedbydryingasampleoftheliquidlatextobeassayedandweighingtheresidue.Thevalueobtainedisthesumofthedryrubbercontentplusthesolidnonrubbercontents,whichincludestheprotein.Latexthatisusedintheproductionofgloves,catheters,andsoonhasaTSCof60~62%.TheDRCoflatexisobtainedb

5、ycoagulatingtherubberinthesampleoflatextobeassayedwithaceticacid,thendrying,washingandweighingtheresultingmassofrubber.ThedifferencebetweentheTRCandtheDRCisameasureoftheofnaturallatex.ThedifferencebetweentheTRCandtheDRCisameasureofthetotalnonrubbercontentsofthelatex.Theselatterconstituentsareprinci

6、pallylatexproteins,lipids,andmineralsalts.InthecaseofHAandLATZlatexes,thosearecommonlyusedintheproductionofgloves,thenonrubberconstituentsmakeupbetween1%and2%ofnaturallatex.2.DeterminationoftheDryRubberContent(DRC)ofLatex3.MeasurementofSurfaceTensionDeterminationofthesurfacetensionoflatexisaveryuse

7、fulmeasure,assurfacetensionisafunctionof:1.Theamountofsoapaddedtostabilizethelatex;2.Thenaturalsoapsformedafterconcentrationfromfattyacidsinthelipidphaseofthelatex;3.Themineralsalts(mg/Na)thatarepresentinth