Designation:D5897−13StandardTestMethodforDeterminationofPercentHydroxylonCelluloseEstersbyPotentiometricTitration—AlternativeMethod1ThisstandardisissuedunderthefixeddesignationD5897;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethodcoversaprocedurefordeterminingthepercenthydroxyloncelluloseestersbypotentiometrictitration.Thetypicalrangeofpercenthydroxylmeasuredis0.7to10.0%.1.2ThevaluesstatedinSIunitsaretoberegardedasstandard.Nootherunitsofmeasurementareincludedinthisstandard.1.3Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.ReferencedDocuments2.1ASTMStandards:2D817TestMethodsofTestingCelluloseAcetatePropionateandCelluloseAcetateButyrateD871TestMethodsofTestingCelluloseAcetate3.SummaryofTestMethod3.1Thecelluloseesterisdissolvedinpyridineandthehydroxylsitesonthecelluloseesterareacetylatedwithaceticanhydrideinthepresenceofbasiccatalyst,1-methylimidazole.Theexcessaceticanhydrideishydrolyzedandtheresultingaceticacidistitratedwithsodiumhydroxide.Anautomatictitratordispensesthetitrant,potentiometricallydeterminestheendpoint,andcalculatesthepercenthydroxylonthecelluloseesterbasedonablankdetermination.4.SignificanceandUse4.1ThistestmethodprovidesasimplermeansforthedeterminationofthehydroxylcontentofcelluloseestersthanthepreparationandmeasurementofthecarbanilatederivativedescribedinTestMethodsD817andD871.4.2Thehydroxylcontentisanimportantindicatorofsolubilityandreactivity.5.Interferences5.1Undissolvedestermayaccumulateonthesidesoftheflaskandontopofthestirring-starduringdissolution,leadingtolowresults.Gentlyswirlingthesolutionduringtitrationcanreducethisp...
