ASTM D5272-2008 可光降解塑料制品的室外曝晒检验的标准实施规程

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【英文标准名称】:StandardPracticeforOutdoorExposureTestingofPhotodegradablePlastics
【原文标准名称】:可光降解塑料制品的室外曝晒检验的标准实施规程
【标准号】:ASTMD5272-2008
【标准状态】:现行
【国别】:美国
【发布日期】:2008
【实施或试行日期】:
【发布单位】:美国材料与试验协会(US-ASTM)
【起草单位】:D20.96
【标准类型】:(Practice)
【标准水平】:()
【中文主题词】:
【英文主题词】:aging;degradableplastic;exteriorexposure;outdoorexposure;photodegradation;ultravioletradiation;weathering;Acceleratedaging/testing--plastics;Degradableplastics;Exposuretests--plastics;Outdoorweathering;Photodegradation;Ultraviole
【摘要】:Whendiscardedaslitter,articlesmadeusingphotodegradableplasticsaresubjecttoattackbydaylight(particularlysolar-ultravioletradiation),oxygen,heat,andwater.The5x00B0;exposureangleusedinthispracticerepresentstypicalconditionsfordegradationexperiencedbylitter.Thispracticerequirescharacterizationofthedurationofexposureintermsofsolar-ultravioletradiation.Solar-ultravioletradiationvariesconsiderablyasafunctionoflocationandtimeofyear.Thiscancausedramaticdifferencesinthetimerequiredtoproduceaspecifiedlevelofdegradationinapolymer.Darohasshownthatwhenthesamelotofpolyethylenecontaininganiron-saltprodegradantisexposedatvarioustimesoftheyearinasinglelocation,thetimerequiredtoproduceanaverageoftwochainscissionspermoleculevariedbyover130%.Daro,andZerlautandAndersonhaveshownthatthisvariabilitycanbesignificantlyreducedwhentotalsolarorsolar-ultravioletradiation,orboth,isusedtocharacterizetheexposureincrements.Inadditiontovariationsinlevelofdaylightandsolar-ultravioletradiation,therearesignificantdifferencesintemperature,andmoisturestressesbetweendifferentlocations,andbetweendifferentyears,orperiodswithinasingleyear,atasinglelocation.Becauseofthisvariability,resultsfromthistestcannotbeusedtopredicttheabsoluterateatwhichphotodegradableplasticsdegrade.Resultsfromthistestcanbeusedtocomparerelativeratesofdegradationformaterialsexposedatthesametimeinthesamelocation.Resultsfrommultipleexposuresofacommonlotofmaterial(duringdifferentseasonsoverseveralyears)atdifferentsitescanbeusedtocomparetherelativeratesatwhichaparticularphotodegradableplasticwilldegradeineachlocation.Note28212;Aninherentlimitationinsolar-radiationmeasurementsisthattheydonotreflecttheeffectsofvariationsintemperatureandmoistureexposure,whichoftencanbeasimportantassolarradiation.Thesamesolar-ultravioletradiationincrementwillnotnecessarilygivethesamechangesinpropertiesofthetestspecimenindifferentexposuresites.Resultsfromthispracticemustberegardedasgivingonlyageneralindicationofthedegreeofdegradabilityandshouldalwaysbeconsideredintermsofcharacteristicsoftheexposuresiteaswell.Wheremeasurementoftotalsolar-ultravioletradiationisnotpossible,exposuredurationcanbedeterminedbythenumberofdays,weeks,ormonthsexposed.Whenthispracticeisused,areferencematerialwhosedegradationpropertieshavebeenwellestablishedmustbeexposedatthesametimeastheothermaterialsbeingtested.Thereferencematerialusedmustbeagreeduponbyallinterestedparties.Thetimetoproduceaspecifiedlevelofdegradationforeachmaterialinthissimultaneousexposureisthencompared.ItisalsoagoodpracticetousereferencematerialswhenexposurelengthisdeterminedbytotalsolarorsolarUVradiantexposure.Note38212;Areferencematerialcanbeasinglelotofmaterialwhichhasshownconsistentresultsafteranumberofexposures.Itisnotnecessarythatthecompositionorpropertiesofthereferencematerialbecharacterizedandcertifiedbyarecognizedstandardsagencyorgroup.FIG.1TypicalRackConstructionforExteriorExposuresofPhotodegradablePlastics1.1ThispracticedefinestestconditionsapplicablewhenPracticesD1435andG7areemployedfortheoutdoorexposuretestingofphotodegradableplastics.1.2Thisst......
【中国标准分类号】:G31
【国际标准分类号】:83_080_01
【页数】:4P.;A4
【正文语种】:英语