聚氨酯聚甲基丙烯酸甲酯有机蒙脱土纳米复合材料的制备结构精.docx

聚氨酯聚甲基丙烯酸甲酯有机蒙脱土纳米复合材料的制备结构精.docx

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聚氨酯聚甲基丙烯酸甲酯有机蒙脱土纳米复合材料的制备结构精

Preparation,structureandpropertiesofpolyurethane/poly（methylmethacrylate/organo2montmorillonitenanocomposites3

FULi2hua,JIADe2min,LIUSa

（DepartmentofPolymerMaterialsScienceandEngineering,

SouthChinaUniversityofTechnology,Guangzhou510640,China

　　Abstract:

Inthispaper,theintercalationtechniqueandinterpenetratingpolymernetworksmethodwerefirstusedtogethertopre2parepolyurethane/poly（methylmethacrylate/organo2montmorillonite（PU/PMMA/OMMTnanocomposite.Thestructureandmorphologyofpolyurethane（PU,interpenetratingpolymernetworkbasedonpolyurethaneandpoly（methylmethacrylate（PU/PMMA2IPN,polyurethane/organo2montmorillonite（PU/OMMTandPU/PMMA/OMMTsystemswerecomparativelyinves2tigatedbyX2raydiffraction（XRDandscanningelectronmicroscopy（SEM.Theresultsshowthatorgano2montmorillonite（OMMTiswelldispersedinpolymermatrixwithparticlesof20~80nminPU/PMMA/OMMTsystem,whichconfirmsthein2terecalatednanocompositeisformed.PU/OMMTisinterecalatednanocompositebecausethed2spacingofOMMTincreasedandtheOMMTisunevendispersedinpolyurethanematrixwiththetactoidsof40~700nm.TheintroduceofOMMTintoPU/PM2MA2IPNsystemmakestheplasticdomainsizeincreasedandthemicrophaseseperationmoreobviouslybetweenPUandPMMAphases.Theresultsofthermogravimetricanalyses（TGAindicatethatthethermalstabilityofPU/PMMA/OMMTnanocom2positeisbetterthanthatofPU/PMMA2IPNandPU/OMMTnanocompositebecausethephasestructurehasbeenimprovedandtheintercalationdegreeofOMMTincreased1.5times.Additionally,themechanicalpropertiesofPU/PMMA/OMMTnano2compositesaresuperiortothoseofothercomparativesystems.

　　Keywords:

polyurethane;montmorillonite;poly（methylmethacrylate;interpenetratingpolymernetworks;nanocomposite

　　CLCnumber:

TB33　　　　　　　Documentcode:

AArticleID:

100129731（200510216382071　Introduction

Pinnavaia[1]andcoworkersfirstreportedthesuperiorpolyurethane/montmorillonite（PU/MMTnanocom2posites,whichattractedtheattentionofresearchersbecauseoftheunprecedentedsuiteofnewandenhancedpropertiesrelativetopurepolyurethaneorconventionalcomposites.Atpresent,twomainmethods,directin2tercalationandsolutionintercalation[2,3],wereusedtopreparePU/MMTnanocomposites.Thenanocompositesoftenexhibitremarkableimprovementsinmechanical[4~6],thermal[7,8],transport[9,10]andbarrier[11]propertieswithalowloadingofclayinthepolymermatrixbecauseofthegoodcompatibilityandstronginteractionbe2tweenpolyurethaneandmontmorillonite.However,thedirectintercalationmethodneededtherigorousreactiveconditions,whichwasdifficultincontrollingthepolymerizationandtheproductproperties.Thesolutioninter2calationmethodneededvastsolvent,whichbrougtaboutcomplexprocessandhighcost.ThusitisnecessarytodevelopanovelandsimplemethodtomodifythePU/MMTnanocomposites.

Interpenetratingpolymernetworks（IPNswereakindofuniquepolymerblendsconsistingoftwoormorecross-linkedpolymersheldtogetherbyinterpenetrationandentanglementofthenetworks[12,13],whichhadat2tractedattentionofresearchersbecauseofthesynergismforproperties[14~18].TheIPNssystemscontainingPUasonenetworkobtainedthemostinterest.TheIPNscanbedividedintotwomajorcategories,dependingontheirsynthesistype:

sequentialIPNswherethemonomers,cross2linkingagents,andinitiatorsofnetworkIIwereswollenintopolymernetworkIandreactedinsitu;andthesimultaneousinterpenetratingnetworks（SINs,wherethedifferentmonomersorpropolymersforbothnetworksweremixedandpolymerizedsimulta2neously.IPNsmethodhastheremarkablemerits,forexample,theinitialviscosityofthesystemislowanditcanbeprocessedeasilywhichcanbenefittonano2intercalatingofPU/MMTnanocomposites.

Inthisstudy,thenano2intercalatingtechniqueandmethodofIPNswerefirstusedtogethertopreparePU/PMMA/OMMTnanocompositesbythemethodofsimultaneousintercalatingpolymerization.Inthereactivesystem,methylmethacrylatetogetherwiththecrosslinkingagent,ethyleneglylenedimethacrylate（EGDMA

3Foundationitem:

SupportedbyGuangdongProvincialNaturalScienceFoundationforGroupProject（39172Receiveddate:

2005206220Modifieddate:

2005208223　　　　Correspondingauthor:

FULi2hua

Biography:

FULi2hua　（1977-,female,Ph.D.,majorinthesysthesisandmodificationofpolymer.

wasintroducedasactivesolventforPU/MMTnanocomposites,whichcaneffectivelysolvetheproblemofrecy2clingsolventandimprovetheprocessingmethod.Additionally,polyurethanebasedonliquid4,42diphenyl2methanediisocyanate（LMDIandpolytetramethyleneglycol（PTMG,PU/PMMA2IPNandPU/OMMTnanocompositewerepreparedandtheirstructureandpropertieswerecomparedwithPU/PMMA/OMMT.ThestructuresandmorphologieswereinspectedbyXRDandSEM.ThethermalpropertieswereinvestigatedbyTGA.Theirmechanicalpropertieswerealsostudied.

2　Experimental

2.1　Rawmaterials

PTMGwithnumberaveragemolecularweightabout2000g/molandhydroxylnumberabout56mgKOH/g（Dupontwasdegassedfor2hat110℃undervacuumtoremovemoisturebeforeuse.Methylmethacrylate（MMA;C.P.gradewaswashedwith10%NaOHsolutionanddistilledwater,thendriedwith0.5nmzeolitebeforeuse.Benzoylperoxide（BPO;C.P.gradewasrecrystallizedbeforeuse.EGDMA（industrialgradewasdriedwith0.5nmzeolitebeforeuse.1,42butanediol（BDO;C.P.gradewasdistilledundervacuumtoremovemoistureanddriedwith0.5nmzeolitebeforeuse.LMDIofMM103（BayerCompanywasusedasreceived.Sodiumbasedmontmorillonite（NaMMTwithion2exchangecapacityof100mequiv/100gwaspurchasedfromNanhaiNonmetalsMineralsCo.（China.OMMTwaspreparedwithacidifiedocamidopropylbetaine（CABinourlaboratoryaccordingtoreference[19].Theotherinorganicandorganicreagentswereavailablecommercially.

2.2　PreparationofPU

ThemixtureofLMDIandPTMGatmolarratioof2.4∶1washeatedto80℃for2htoformanisocyanateterminatedpolyurethaneprepolymerwhichwasvacuumdegassedat80℃untiltherewasnogasinit.Thestoi2chiometricBDOwasaddedtothisprepolymerat90℃understirringwithinseveralminutes,thenthemixturewaspouredintoametalmold,curedat110℃for24h,placedatambienttemperatureforoneweekbeforetest.

2.3　PreparationofPU/OMMTnanocomposites

ThestoichiometricmixtureofPTMGandOMMTwasheatedto60℃underrapidstirringfor24h.TheLMDIwith2.57molartimesofPTMGwasaddedtothemixtureofPTMGandOMMT,thenthenewmixturewasheatedto80℃for2htoformanisocyanateterminatedpolyurethaneprepolymerwithOMMTwhichwasvacuumdegassedat80℃untiltherewasnogasinit.ThestoichiometricBDOwasaddedtothisprepolymerat90℃underrapidstirringwithinseveralminutes,thenthemixturewaspouredintoametalmold,curedat110℃for24h,placedatambienttemperatureforoneweekbeforetest.

2.4　PreparationofPU/PMMA2IPN

ThemixtureofLMDIandPTMGatmolarratioof2.4∶1washeatedto80℃for2htoformanisocyanateterminatedpolyurethaneprepolymer.TheisocyanateterminatedpolyurethaneprepolymerwasevenlymixedwithBDO,MMA,EGDMA,BPOandN,N2dimethylaniline（DMAatstoichiometricweightratiosinareac2tionkettleatambienttemperature.Thenthelastmixturewasdegassedatvacuumforseveralminutes,pouredintoametalmold,reactedatambienttemperatureforabout10h,curedat110℃for24h,placedatambienttemperatureforoneweekbeforetest.

2.5　PreparationofPU/PMMA/OMMTnanocomposites

ThestoichiomtricPTMG,OMMTandMMAwereblendedbyultrasonicinstrumentatambienttempera2turefor30min.TheLMDIwith2.63molartimesofPTMGwasaddedtothemixtureofPTMG,OMMTandMMA,thenthenewmixturewasheatedto80℃for2htoformanisocyanateterminatedpolyurethaneprepoly2merwithOMMTaswellasMMA.ThestoichiometricMMA,BDO,EGDMA,BPOandDMAwereaddedtothisprepolymerinareactionkettle.Thewholemixturewasthoroughlyblendedatambienttemperaturequicklyandvacuumdegassedwithinseveralminutes,thenthemixturewaspouredintoametalmold,reactedatacer2taintemperatureforabout10handcuredat110℃for24handplacedatambienttemperatureforoneweekbe2foredetermination.

2.6　Measurement

Tensilestrength,elongationatbreakandtensilemodulusweremeasuredaccordingtoGB/T52821998withUT22060electronicuniversaltestingmachineatambienttemperatureatacross-headspeedof（500±50mm/

min.TearstrengthwasmeasuredaccordingtoGB/T52921999withUT22060electronicuniversaltestingma2chineatambienttemperatureatacross2headspeedof（500±50mm/min.ShoreAhardnesswasperformedac2cordingtoGB/T53121999withshoreAsclerometeratambienttemperature.XRDmeasurementsonthepowdersamplesandnanocompositessliceswereperformedwithaD/MAX2ⅢpowderdiffractometerequippedwithCuKαradiation（λ=15.4nm.SEMmeasurementswereperformedwithanXL230FEGscanningelectronmicro2scopebyPhillps.Sampleswerepreparedbyfracturingthespecimensatliquidnitrogentemperatureandweregold2coated.TGAofsampleswerecarriedoutunderN2atmosphereonanAmericanTAInstrumentsModulatedTGA2050ataheatingrateof10℃/min.

3　Resultsanddiscussion

3.1　Structureandmorphologyofdifferentsystems

Therewerethreekindsofpolymer2layeredsilicatenanocomposites:

intercalated,intercalated/exfoliatedandexfoliatednanocomposites[20].XRDwasaneffectivemethodfortheevaluationoftheintercalationcapabilityofpolymers.TheexpansionoflayersoforganoclaycanbedetectedbyXRD.Andt