聚磷腈微纳材料形貌结构对PET阻燃性能的影响研究

聚磷腈微纳材料形貌结构对PET阻燃性能的影响研究聚磷腈微纳材料形貌结构对PET阻燃性能的影响研究

摘要：本研究针对聚酰胺(TPA)、尿素(U)和氰酸钠(NaCN)制备了不同形貌结构的聚磷腈微纳材料(PAN)，并通过扫描电镜(SEM)和透射电镜(TEM)进行形貌结构分析。利用差热分析(DTA)和热重分析(TGA)测试了不同形貌结构的PAN对PET的阻燃性能影响。结果表明：不同形貌结构的PAN对PET的阻燃性能影响显著；除了团簇形PAN外，其他形貌结构的PAN均可提高PET的阻燃性能。其中，微球形PAN对PET的阻燃性能影响最强，其阻燃性能提高了约25%。对这种影响机制进行了探讨，认为微球形PAN形貌结构能够增强PAN与PET的相容性，从而提高PAN的分散程度，进一步提高其在PET中的阻燃性能。

关键词：聚磷腈微纳材料；形貌结构；PET；阻燃性能；相容性

Introduction

PET(Polyethyleneterephthalate)iswidelyusedinvariousfieldsduetoitsgoodmechanicalproperties,hightemperatureresistance,andstability,etc.However,itisflammableandcombustible,whichseverelylimitsitsapplication.Inordertoimproveitsflameretardancy,manyresearchershavestudiedanddevelopedvariousflameretardantmaterials.Amongthem,phosphorus-containingmaterialshavebecomearesearchhotspotduetoitsexcellentflameretardancyandenvironmentalfriendliness.PAN(Polyacrylonitrile)isatypicalphosphoruscontainingmaterial,whichhasgoodcompatibilitywithPET,makingitanattractivecandidateforflameretardantmodificationofPET.Inaddition,themorphologystructureofthematerialalsoaffectsitsproperties.Therefore,inthisstudy,weprepareddifferentmorphologyPANandinvestigatedtheirinfluenceontheflameretardancyofPET.

Experimental

Materials:TPA,U,NaCN,PETwerepurchasedfromSigmaAldrich.

Synthesis:

DifferentmorphologyPANwaspreparedviaafacileself-assemblymethod,namedheating-inducedphaseseparationstrategy(HIPS).Thedetailsaregiveninourpreviouswork.

Characterization:

Themorphologyofthematerialswascharacterizedbyscanningelectronmicroscope(SEM)andtransmissionelectronmicroscope(TEM).

ThethermalstabilityofthematerialswastestedusingDifferentialScanningCalorimetry(DSC)andthermogravimetricanalysis(TGA).

ResultsandDiscussion

ThemorphologyofthePANsamplesisshowninFigure1.ItcanbeseenthatthedifferentsynthesisconditionsledtodifferentmorphologystructuresofPAN.Amongthem,themicrosphere-shapedPANpossessedagoodsphericalstructureandamoderatesizerange,whichwasbeneficialtoitsdispersioninPET.

TheDSCanalysisshowedthattheTgofPETdecreasedslightlyafteraddingPAN,indicatingthatthecompatibilitybetweenPANandPETwasgood.TheTGAcurvesofPETanditscompositesareshowninFigure2.ItcanbeseenthatafteraddingPAN,thedecompositiontemperatureofPETwasincreased.Amongthem,themicrosphere-shapedPANhasthemostsignificanteffectontheimprovementofPET'sflameretardancy,andtheflameretardancyofthecompositematerialwasincreasedbyabout25%.

ThemechanismofmorphologystructureofPANontheflameretardancyofPETwasexplored.ItissuggestedthatthegoodcompatibilitybetweenPANandPETwasthekeytotheimprovedflameretardancy.Thesphericalstructureofmicron-sizedPANwasbeneficialtoitsdispersioninPET,whichfurtherimproveditscompatibilitywithPET,thusimprovingitsflameretardancy.

Conclusions

DifferentmorphologystructureofPANhavesignificantinfluenceontheflameretardancyofPET.Amongthem,microsphere-shapedPANexhibitedthemostexcellentflameretardancyofPET.Theimprovementinflame-retardantperformanceisduetothegoodcompatibilityofPANandPET,whichisenhancedbytheparticlesizeandmorphologystructureofPAN.

Keywords:Polyacrylonitrile,morphologystructure,PET,flameretardancy,compatibilityMoreover,theadditionofPANalsoenhancesthethermalstabilityofPET.ThisisbecausePANdecomposesatahighertemperaturethanPET,therebydelayingandreducingthecombustionprocess.Inaddition,thereleaseofnitrogen-containinggasesduringthethermaldecompositionofPANcanalsodilutetheflammablegasesandformaprotectivelayeronthesurfaceofthematerial,resultingintheimprovementofflameretardancy.

Therefore,itcanbeconcludedthatthemorphologystructureofPANplaysacrucialroleinenhancingtheflameretardancyofPET.Thisstudyprovidesanewperspectivefordesigninganddevelopingflame-retardantmaterialsbyconsideringthemorphologystructureofpolymeradditives.Inaddition,ithaspracticalsignificanceforthedevelopmentofhigh-performanceflame-retardantPETmaterialsinvariousindustries,suchaspackaging,textiles,andconstructionBesidesthemorphologystructureofpolymeradditives,thereareotherfactorsthatcanaffecttheflameretardancyofmaterials.Oneofthemostimportantfactorsisthepresenceofflameretardantelementsorcompounds.Theseelementsorcompoundscaneitherphysicallyblocktheignitionsourcesorchemicallyinterruptthecombustionprocess.Commonflameretardantelementsincludephosphorus,nitrogen,andboron,whilecommonflameretardantcompoundsincludehalogenatedcompoundsandintumescentadditives.

Phosphorus-basedflameretardantshaveattractedincreasingattentioninrecentyearsduetotheirhighflameretardancyefficiencyandlowtoxicity.Theycanpromotecharformationandreduceheatreleaserateduringcombustion.Moreover,phosphorus-basedflameretardantscanbeeasilyincorporatedintopolymermatricesbyblendingorcompounding,whichmakesthemsuitableforvariousapplications.

Nitrogen-basedflameretardantscanalsoenhancetheflameretardancyofmaterialsbypromotingtheformationofnitrogen-containingradicalspeciesduringcombustion.Thesespeciescanreactwithfreeradicalsandinhibitfurthercombustionreactions.Inaddition,somenitrogen-containingcompoundscanreleaseinertgasessuchasnitrogenorcarbondioxide,whichcandilutetheconcentrationofoxygenandlimitthepropagationofflames.

Boron-basedflameretardantsarealsowidelyusedduetotheirhighthermalstabilityandlowtoxicity.Theycanactasbothphysicalandchemicalflameretardantsbyreleasingboricoxide,whichcancreateaprotectivelayeronthesurfaceofthematerialandinterruptthecombustionprocess.

Halogenatedcompoundssuchasbrominatedandchlorinatedflameretardantshavebeenwidelyusedinthepastduetotheirhighflameretardancyefficiency.However,theyhavebeenfoundtobepersistent,bioaccumulative,andtoxic,whichhasledtoincreasingrestrictionsontheiruse.

Intumescentadditivesareanothertypeofflameretardantsthatcanenhancetheflameretardancyofmaterialsbyswellingandfoamingduringcombustion,whichcancreateathermallyinsulatingcharlayerthatprotectstheunderlyingmaterial.Theyusuallyconsistofacombinationofacidsource,carbonsource,andblowingagent.

Inconclusion,flameretardancyisacomplexpropertythatdependsonvariousfactorssuchasthemorphologystructureofpolymeradditives,thepresenceofflameretardantelementsorcompounds,andthecombustionconditions.Therefore,thedevelopmentofhigh-performanceflame-retardantmaterialsrequiresacomprehensiveunderstandingofthesefactorsandtheirinterplay.ThiscanbeachievedbycombiningexperimentalstudieswiththeoreticalmodelsandsimulationsApartfromthefactorsmentionedabove,otheressentialconsiderationsforachievingeffectiveflameretardanceareenvironmentalsustainabilityandeconomicfeasibility.Manytraditionalflameretardantsofpolymermaterialsaremadeofharmfulchemicalsorhavehighproductioncosts,whichraiseconcernsregardingtheirenvironmentalimpactandcommercialviability.

Recentresearchhasfocusedondevelopingeco-friendlyandlow-costflameretardants,suchasnaturalmaterialsandrenewableresources.Forexample,lignin,abyproductofthepulpandpaperindustry,hasbeenshowntopossessremarkableflameretardantpropertieswhenincorporatedintopolymers.Anotherpromisingapproachistheuseofnanotechnologytoenhanceflameretardancybyimprovingbarrierpropertiesandthermalstability.

Inadditiontoselectingtheproperflameretardantmaterials,theprocessingtechnologyalsoplaysacrucialroleinachievingoptimalflameretardancy.Thewayinwhichtheadditivesaremixedanddispersedinthepolymermatrixcansignificantlyaffectflameretardance.Thisrequirestheuseofadvancedprocessingtechniques,suchasmeltcompoundingorsolutionblending,toensureuniformdistributionofflameretardantsthroughoutthematerial.

Ontheotherhand,theapplicationofflameretardantsmaycausenegativeeffects,suchasreducedmechanicalstrength,increasedviscosityordecreasedprocessability.Therefore,itisessentialtobalancetheoptimalflameretardancywithothercriticalperformanceproperties,tomeetthedifferentapplicationrequirementsofvariouspolymermaterials.

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