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.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
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- 关 键 词:
- 聚氨酯 甲基丙烯酸 有机 蒙脱土 纳米 复合材料 制备 结构