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高分子化學(xué)
Polymerchemistry高分子化學(xué)
Polymerchemistry
RADICALPOLYMERIZATION自由基聚合
RADICALPOLYMERIZATION3.1MechanismofRadicalPolymerization3.2InitiatorsandInitiation3.3RateofRadicalPolymerization3.4MolecularWeightandChainTransferReaction3.5ThermodynamicsofPolymerization3.6MethodsofPolymerization3.1MechanismofRadicalPolyAnImportantOneofChainPolymerizationFamilyClassifiedbythenatureofreactivecenter:
radicalpolymerization
cationicpolymerization
anionicpolymerization
coordinatingionicpolymerizationandsoon.AnImportantOneofChainPolyChainpolymerizationconsistsofasequenceofthreesteps:
InitiationreactionPropagationreactionTerminationreactionChainpolymerizationconsists
PrimaryRadical引發(fā)劑
Initiator
Primary引發(fā)劑Initiator
MonomerRadicalPrimaryRadicalMonomerPrimary
MonomerRadical
ChainRadicalMonomerChainMacromoleculeMacromolecule高分子化學(xué)-Polymer-chemistry3自由基引論RADICAL-POLYMERIZATION課件TheRadicalPolymerizationisaveryImportantReactioninPolymerChemistryAleadingpositioninindustry:Productsofradicalpolymerizationcontributetomorethansixtypercentofthetotalproductionofpolymer,andeightypercentofthermoplasticresin.
TheRadicalPolymerizationisApracticallyperfecttheory:
Thegenerationandpropertyofradicalactivecenter;allelementaryreactionsandthereactionmechanism;thedynamicsofpolymerizationreaction;themolecularweightandthefactorsaffectingmolecularweight;Thermodynamictheory:AfullydevelopedtheoryThesehavebeenthetheoriesessentialtothestudyofionicandcoordinationpolymerization.Apracticallyperfecttheory:Table3.1ThepolymeroftheRadicalPolymerization
polyethylenePE
polystyrenePSpolyvinylchloride
PVCpolyvinylidenechloridePVDCTable3.1ThepolymerofthepolyvinylfluoridePVFpolytetrafluoroethylenePTFEpolychlorotrifluoroethylenePCTFE
polyacrylicacidPAA
polyacrylamidePAM
polymethylacrylatePMApolyvinylfluoridePVFpolymethylmethacrylatePMMApolyacrylonitrilePAN
polyvinylacetatePVAc
polybutadienePBpolyisoprenePIP
polychloroprenePCPpolymethylmethacrylate3.1
RadicalPolymerizationMechanism3.1.1Theactivityandthereactionofthefreeradical3.1.2Monomerstructureandtypesofpolymer-ization3.1.3Elementaryreactionsoftheradicalpolymer-ization3.1.4Characteristicsoftheradicalpolymerizationreaction3.1RadicalPolymerizationMe3.1.1
TheactivityandthereactionofthefreeradicalFreeradicalcanbeformedifthereareunpairedelectronorloneelectron.Theelectroniscalledmonoradicalifitistheonlyunpairedelectron.Ifthereareonlytwounpairedelectrons,theyarecalleddiradical.3.1.1TheactivityandthereaFreeRadicals
AtomicradicalsMolecularradicalsIonicradicals
ElectroneutralcompoundresidueFreeRadicalsAtomicradicalsGenerationofFreeRadicals
Thermaldecomposition
PhotochemicaldecompositionOxidation-ReductionreactionHighenergyparticleradiationGenerationofFreeRadicalsT(1)ActivityofTheFreeRadical
Theactivityofafreeradicalisdeterminedbyitsstructure.
Thestrongertheconjugativeeffectofafreeradical,themorestableitis.Polargrouplessenstheactivityofthefreeradical.Bulkygroup
lessenstheactivityofreaction,becauseitpreventsthenearingofthereagent.
(1)ActivityofTheFreeRadicTheOrderoftheRelativeActivity
ofRadicalsTheRadicalsinthelastlinearetheinertradicalsthathavenoabilityofinitiatingolefinicmonomers’polymerization
TheOrderoftheRelativeActi(2)ReactionsofRadicals
TheRadicaladditionreactionTheRadicalcouplingreactionTheRadicaldisproportionationreactionTheRadicaldissociationreactionTheRadicaltransferreaction(2)ReactionsofRadicalsTheR
①RadicalAdditionReaction
...
①RadicalAdditionReaction
.②RadicalCouplingReaction②RadicalCouplingReaction③RadicalDisproportionationReaction③RadicalDisproportionationR
④RadicalDissociationReaction
④RadicalDissociationReacti
⑤RadicalTransferReaction
⑤RadicalTransferReaction
Mostofthemonoolefin,conjugateddiolefin,alkyne,
andcarbonylcompounds,andsomeoftheheterocycliccompoundscanbepolymerizedfromthethermodynamicviewpoint.
3.1.2
MonomerStructureand
PolymerizationTypesMostofthemonoolefin,conjHowever,
theselectivityofthevariousmonomerstodifferentpolymerizationmechanismsvariesgreatly.However,theselectivityofExamples
Vinylchlorideonlycanundergoradicalpoly-merization.Isobutyleneonlycanundergocationicpolymer-ization.Methylmethacrylatecanundergoradicalaswellasanionicpolymerization.Styrenecanundergoradical,anionic,cationic,andcoordinationpolymerization.ExamplesVinylchlorideonlyWhatmakesthedifferencesismainlydecidedbythestructureofthesubstitu-entonthecarbon-carbondoublebond,andisalsodecidedbytheelectroniceffectandthestericeffectofthesubstituent.Ethylene,themostsimplealkene,withasymmetricstructure,canundergoradicalpolymerizationunderhighpressure,
andcoordinationpolymerizationbyparticularinitiatorsystems.WhatmakesthedifferencesisMonosubsititutedAlkeneDoubleBondMonomersCH2=CH-X,theelectroniceffectofthesubstituentsXinvolvestheinductiveorresonanceeffect.Theeffectofsubstituentmanifestsitselfbyitsalterationofelectron-clouddensityonthedoublebondandithastheabilitytoaffectthestabilityoftheactivecenter.MonosubsititutedAlkeneDoublWhetheranalkenepolymerizesbyradical,anionic,orcationicinitiatorsdependsontheinductiveandresonancecharacteristicsofthesubstituentspresent.WhetheranalkenepolymerizesToCH2=CH-X,whenXiselectron-pushingsubstituentItincreasestheelectron-clouddensity,facilitatingitsbondingtoacationicspecies.
Further,thesesubstituentsstabilizethecationicpropagatingspeciesbyresonance,anddecreasetheactivationenergyofthereaction.Thus,electron-pushingsubstituentsfacilitatethemonomerstocationicpolymerization.ToCH2=CH-X,whenXiselectrElectron-pushing
substituentssuchasalkyl,alkoxy,phenyl,andalkenylTheeffectofalkylgroupsinfacilitatingcationicpolymerizationisweak,
Anditisonlythe1,1-disubstitutedalkeneswhichundergocationicpolymerization.
CH3
CH2=CCH2=CHCH3ORElectron-pushingsubstituents
ToCH2=CH-X,whenXis
electron-
withdrawingsubstituent
Itlowerstheelectron-density,andstabilizesthepropagatinganionicspeciesbyresonance.And,thus,itfacilitiesanionicpolymerizationofthemonomers.
ToCH2=CH-X,whenXis
eleElectron-withdrawingsubstituents:cyanoandcarbonyl(aldehyde,ketone,acid,orester)Radicalpolymerizationissomewhatsimilartoanionicpolymerization.Electron-withdrawingsubstituentsfacilitatetheattackofananionicspeciesbydecreasingtheelectron-densityonthedoublebond.Theystabilizethepropagatingofanionicspeciesbyresonance,whichweakenstheactivationenergyofthereaction.Electron-withdrawingsubstituStrongelectron-withdrawingsubstituents
facilitatethemonomerstoanionicpolymeri-
zationwithweakeronesincliningtoradical
polymerizationMonomerswithsubstituentsbetweenthetwocanundergoeitheranionicorradicalpolymerization.Halogensubstituents,althoughelectron-withdrawinginductively,canresonancestabilizetheanionicpropagatingspecies,however,bothoftheeffectsareweak.Strongelectron-withdrawingConjugated
AlkeneStyrene,butadiene,isoprene,andotherconjugatedalkene,becauseofitsstrongdelocalizationoftheπ-bond,areeasytobeinducedandpolarized,thus,canundergoallofthefourmodespolymerizationmentionedabove.CH2=CH-CH=CH2CH2=C-CH=CH2CH3CH2=CHConjugatedAlkeneStyrene,butStericEffect
oftheSubstituentStericEffect-----thevolume,amount,andlocationofthesubstituent.
Inkinetics-----Itproducesanoticeableeffectonthecapabilityofpolymerization.However,itusuallydoesn’tcontaintheselectivitytodifferentactivecenters.StericeffectsofmonosubstituentsarenotobviousStericEffectoftheSubstitue1,1-disubstitutedalkenemonomersStericeffectsusuallybeingignored,
theactivityandselectivityofthemonomersareonlythoughttobedecidedbytheelectron-effectofbothsubstituents.However,whenbothofthesubstituentsarephenylgroups,becauseofitslargebulk,monomerscanonlyformdipolymer.
RCH2=CR’1,1-disubstitutedalkenemonom1,2-disubstitutedmonomersOwingtostrongstericeffect,thiskindofmonomersareusuallyhardtopolymerize.
Forexample,maleicanhydrideishardtohomopolymerize,butcancopolymerizewithstyreneorvinylacetate.
CH=CHRR’1,2-disubstitutedmonomersOwinTriortetrasubstitutedethyleneTheyususllycannotpolymerize.But,thereareanexceptionwhenthesubstituentisfluorin.Owingtothesmallradiusofthefluorin,allofthem,
frommonototetrasubstitutedfluoroethylene,
canpolymerizewell.Triortetrasubstitutedethyle3.1.3
ElementaryReactionsofRadicalPolymerizationRadicalpolymerizationischainpolymerizationComposedbyatlestthreeelementaryreactionsChaininitiationChainpropagationChainterminationPerhapsaccompaniedbychaintransferreactionandsoon3.1.3ElementaryReactionsof
PrimaryRadical
MonomerRadical(1)ChainInitiationReaction
heatabsorptionheatliberation
Initiator
MonomerPrimaryMonomer(1)ChainInit
PrimaryRadicalThedecompositionofinitiatorsisaheatabsorp-tion
reaction.Witharelativelyhighactivationemergy,about100~170KJ/molPrimaryRadicalPrimaryThedecompositionofDecompositionrateconstantisusually
10-4~10-6/s
Thereactionrateisrelativelyslow.Initiatordecompositionreaction-----controlstheoverallrateofthechaininitiation.Decompositionrateco
MonomerRadical
MonomerTheprimaryradicalsaddtomonomerstoproducemonomerradicals.Theprocessofopeningaπ-bond,andproducingaσ-bondisaexothermalreaction.MonomerRadicalMonomerMonomerTheprimaryraWithalowactivationenergy,about20~34kJ/mol
Andagreatreactionrateconstant.Thisisaveryfastreaction.
Withalowactivationenergy,(2)ChainPropagationReaction
(2)ChainPropagationReactionHead-to-TailstructureHead-to-HeadstructureTail-to-TailstructureHead-to-TailstructureHead-to-(3)ChainTerminationReactionRadicalExhaustionCouplingTerminationDisproportionationTermination(3)ChainTerminationReactionR
Monoradicaltermination------
ExhaustsoneradicalinitiatorBiradicaltermination------couplingtermination;disproportionationterminationMonoradicaltermination------Biradicaltermination------
couplingtermination;
disproportionationterminationCouplingTermination----Thedegreeofpolymerizationisthesumofthemonomericunitsofthetworadicalchains.
Thetwoendsofthemoleculearetheresiduesoftheinitiators.Biradicaltermination------
Terminationofdisproportionation----TheDegreeofPolymerizationisthenumberofthemonomericunitsoftheradicalchain.Eachmoleculecontainsainitiatorresiduesend.However,theterminatedchemicalstructuresofthetwomoleculesaredifferent,onesaturated,andtheotherunsaturated.TerminationofdisproportionatThemodesofterminationreactionsaredeterminedbythemonomerstructureandthepolymerizationtemperature.
ThemodesofterminationreacThemodesoftermination------
monomerstructure
polymerization
temperatureWithbulksubstituents-----thepossibilityofdisproportionationterminationincreases.Atlowpolymerizationtemperature----tendingtocouplingtermination.Themodesoftermination------Therelativescaleofcouplingtodisproportionationterminationis:TherelativescaleofcouplingTable3-3ModesofsomeMonomerRadicalTerminationPolymerizationcouplingDisproportionationMonomerstemperaterminationterminationStyrene0~60℃100%0%
P-chlorostyrene
60、801000P-anisole
styrene
608119805347Methylmethacrylate04060253268601585
Acrylonitrile40,60928
Vinylacetate90~100Table3-3ModesofsomeMonomTable3-4ComparisonbetweenChainPropagationandChainTerminationReactionPropagationrateconstant[L/(mol·s)]Monomerconcentration[M]:10~10-1[mol/L]Propagationrate[M][M·],10-4~106[mol/(L·s)]Rateconstantoftermination
[L/(mol·s)]Radicalconcentration[M·]:10-7~10-10[mol/L]Terminationrate[M·]2,10-8~10-10[mol/(L·s)]Table3-4Comparisonbetween(4)ChainTransferReaction
TomonomerTosolvent(ortochaintransferagent)ToinitiatorTopolymer
(4)ChainTransferReactionTo
[1]
tomonomer[2]
Tosolvent(ortochaintransferagent)[1]
tomonomer[2]Tosolven[3]
toinitiator[4]
tomolecule[3]
toinitiator[4]
tomoCharacteristicsofRadicalPolymerizationFrommicroscopicview,radicalreactionconsistsoffourelementaryreactions--initiation,propagation,termination,andtransfer.Therateofinitiationisthelowestone,whichcontrolstheoverallrateofpolymerization.Inconclusion,thecharacteristicsofradicalpolymerizationareslowinitiation,fastpropagation,fasttermination,andeasytransfer.CharacteristicsofRadicalPolThedegreeofpolymerizationincreasesonlyinthepropagationprocess.Inthesystemthereareonlymonomersandpolymers,nointermediatecompounds.ThedegreeofpolymerizationiProlongingthereactiontimeismainlytoincreasetheconversionrate,withlittleeffectsonthemolecular-weight.However,geleffectwillincreasethemolecular-weight.Asmallamount(0.01%~0.1%)ofinhibitorsisenoughtoterminatetheradicalpolymerization.ProlongingthereactiontimeRadicalPolymerizationCondensationPolymerizationElementaryreactions’rateconstantsandactivationenergyaredifferentElementaryreactions’rateconstantsandactivationenergyarealmostsamelyDegreeofpolymerizationdoesnotchangewithpolymerizationtime
Molecularweightincreasesgraduallyandafairlylongtimeisneeded.Thepolymermolecularwei-ghtiscomparativelysmallNointermediateproductswhosedegreeofpolymeri-zationareincreasingPolymerizationprocessinvolvesallmonomersTable3-5ComparisonoftheCharacteristicsofRadicalandCondensation
PolymerizationRadicalPolymerizationCondensaRadicalPolymerizationCondensationPolymerizationNoremarkablechangeofmolecularweightwithprolongedreactiontimeandhigherconver-sion.
Molecularweightofproductincreaseswithpolymerizationtimebutconversionincreaseslittle
exothermicreactionShouldbeheatedtohightemparetureAccompaniedwithrobabilitiesofbranch-ingandevencrosslinkingNobranchingRadicalPolymerizationCondensa3.2InitiatorandInitiation3.2.1TypesofInitiators3.2.2KineticsofInitiatorDecomposition(1)InitiatorDecompositionRate(2)InitiatorEfficiency(3)ChoiceofInitiator3.2.3OtherInitiation(1)Thermal-initiatedpolymerization(2)Lightinitiatedpolymerization(3)Highenergyradiationinitiatedpolymerization3.2InitiatorandInitiation3.3.2
InitiatorandInitiationInitiationisaprocesswhichconvertsolefinicmonomerstoradicals.Primaryradicalscanbeproducedthroughlight,heat,orhighenergyradiationdirectlyactingonmonomers.But,whatusedmoreoftenisinitiator.Initiatorshaveweakbonds,Thermaldecompositioncanproducetwoprimaryradicals.3.2InitiatorandInitiationIn3.2.1TypesofInitiatorsAzoinitiatorOrganicperoxideinitiatorInorganicperoxideinitiatorRedoxinitiationsystem
3.2.1TypesofInitiatorsAzoi(1)AzoInitiator
azobisisobutyronitrile(AIBN)
azo-bis-iso-heptonitrile(1)AzoInitiatorazobisisobut(2)OrganicPeroxideInitiatordibenzoylperoxidedialkylperoxide
(2)OrganicPeroxideInitiator(3)InorganicPeroxideInitiatorpersulphate(3)InorganicPeroxideInitiato(4)Redoxinitiationsystemcomponents:inorganicandorganicproperties:oleiferous
solubilityandaqueoussolubility(4)RedoxinitiationsystemcompforinstanceThermaldecompositionactivationenergyFrom200downgradeto40KJ/mol
From125downgradeto50KJ/molFrom140downgradeto50KJ/molIntheredoxsystemofaqueoussolubility,inorganicreducersareusuallyused,andasmallamountof
organicreducers,suchasalcohol,amine,andsoon,areusedtoo.
forinstanceThermaldecompositSystemsofOleiferous
SolubilityareOftenUsedInitiatorstertiaryamine,naphthenate,mercaptan,metalloorganiccompoundSystemsofOleiferousSolubiliExamplebenzoylperoxideandN,N-dimethylanilineinitiatingsystemExamplebenzoylperoxideandN,
SomemetalloorganiccompoundsTaketrialkylboranelforexample,itcanreactwiththeoxygenintheair,andformaredoxinitiationsystem,whichcaninitiateolefinicmonomerspolymerizationatalowtemperature.Somemetalloorganiccompound3.2.2
DecompositionKineticsofInitiatorIneachelementaryreactionofradicalpolymerizationInitiationrateisthelowestone.Haveastrongeffectonbothoverallpolymerizationrateandmolecularweight.ChaininitiationrateControlledbytheinitiatordecompositionrate.Bystudyingtheinitiatordecompositionrate,wecanfindthequantitativerelationshipbetweentheradicalgenerationrateandtheinitiatorconcentration,temperature,andtime.
3.2.2DecompositionKineticso(1)ThermalDecompositionRateofInitiatorInitiatorthermaldecompositionisafirstorderreaction.initiatorPrimaryradicalDecompositionrateofinitiatormol/(L·s)
Rateconstantfordecompositions-1
integratedAtagiventemperature,throughtheplotofln([I]
/[I]0)totimet
Rateexpression(1)ThermalDecompositionRate(1)ThermalDecompositionRateofInitiatortheplotofln([I]
/[I]0)totItsslope=-kd
ln([I]
/[I]0)t/min0.0-0.4-0.80.080160240320=[(-0.4)-(-0.8)]/(160-320)60=-4.2x10-5(s-1)(1)ThermalDecompositionRateThehalflifeofthefirstorderreaction-t1/2
Tothefirstorderreaction,weusuallytakethehalflifetocharacterizethereactionrate.Halflifeisthetimeneededfortheinitiatortodecomposetohalfitsoriginalconcentration.
ThehalflifeofthefirstordeArrheniusformulation
ThedependenceoftherateconstantforinitiatordecompositionontemperatureisinconformitytoArrheniusformulation.Theplotoflnkdto1/Tshouldbeastraightline.Frequency
factor-Adcanbeworkedoutfromtheintercepting.
Thedecompositionfreeenergy-Ed
canbeworkedoutfromtheslope.ArrheniusformulationThedepeTable3-6KineticParameterof
SomeTypicalInitiators
InitiatorssolventT/oCkd/S-1t1/2/hEd/kj/molAIBN502.64*10-673128.460.51.16*10-516.669.53.78*10-55.1BPObenzene602.0*10-696124.3802.5*10-57.7cuminehydroperoxide
toluene1259*10-621.41393*10-56.4potassiumPersulphate0.1mol/603.16*10-661140.2L.KOH702.33*10-58.3Table3-6KineticParametero(2)EfficiencyofInitiationOnlyapartofprimaryradicalsareeffectiveininitiatingmonomerspolymerizing.Someinitiatorsareexhausted,becauseofthesidereactionsaccompanyingwiththe
induceddecomposition,and/orthecageeffect.
Theefficiencyofinitiationisdefinedastheratioofinitiatorswhichareusedtoinitiatepolymerizationtoinitiatorsthatdecomposeinthewholeprocessofpolymerization,andisdenotedasf.
(2)EfficiencyofInitiationOnl①InducedDecompositionofInitiatorsThechaintransferreactionfromfreeradicalstoinitiatormolecules.Thetotalnumberoffreeradicalsarenotincreased,however,oneinitiatorisexhausted,whichlowerstheefficiencyofinitiation.①InducedDecompositionofInFactorsImpactontheEfficiencyofInitiationTheefficiencyofinitiationdependsontheinitiatortype.TheinduceddecompositionofAIBNisverylittle.Hydroperoxideeasilyundergoesinduceddecomposition,whichmakestheefficiencyofinitiationlowerthan0.5.FactorsImpactontheEfficienThetypeofmonomersalsoaffectstheefficiencyofinitiation.Monomerswithhighactivity,suchasstyrene,andacrylonitrile,canreactwiththefreeradicalsrapidly,andreducetheinduceddecomposition.Incontrast,theabilityofcapturingfreeradicalsisrelativelypoorforvinylacetatetypemonomers,sothevalueoffisfairlylow.ThetypeofmonomersalsoaffeDecompositionRateofInitiatorsInduceddecompositionusuallyincreasesRd,anddecreasest1/2.Whenaccompaniedbyinduceddecomposition,thedecompositionrateofinitiatorscanbeexpressedbyNormalfirstorderdecompositionrateInduceddecompositionrateBetween1and2
DecompositionRateofInitiato②CageEffectTheinitiatorconcentrationisverylowinpolymerizationsystem,sotheprimary
radicalsarebesiegedbythecageofsolventmolecules.
Inordernottoreactwitheachother,primaryradicalsmustgetoutofthecage.Thelifeexpectancyoffreeradicalsinthecageisabout
10-11~10-9S②CageEffectTheinitiatorconForexampleSidereactionsofcageeffectofAIBNForexampleSidereactionsofc
SidereactionsofcageeffectofBPOSidereactionsofcageeffect
Table3-7EfficiencyofInitiationofAIBNTheefficiencyofinitiationdependsontheinitiators,monomers,solvent,systemviscosity,andotherfactors.ThevalueoffofAIBNtodifferentmonomersMonomersf,%Monomersf,%AN~100VC70~77Styrene~80MMA52VAC68~82Table3-7EfficiencyofIniti③TheChooseofInitiatorsFirstly,accordingtothepolymerizationmethods,Initiatorswitholeiferous
solubilityareOKforbulk,solution,andsuspensionpolymerization.InitiatorswithaqueoussolubilityareOKforemulsionpolymerization.Secondly,accordingtothehalflife,
Thechoseninitiatorshouldhaveahalflifecomparativetoorofthesameorderwiththetimeofpolymerization③TheChooseofInitiatorsFirsThirdly,thedosageofinitiatorshouldbereasonable,Theinitiatorconcentration[I]affectsnotonlytherateofpolymerization,butalsothemolecularweightoftheproducts,further,ithasaoppositeeffect(aftermentioned)Theproperinitiatorconcentrationdependsonanamountofexperiments.Thirdly,thedosageofinitiatInaddition,suchasprice,source,toxicity,stability,theeffectonthecolorshadeofpolymers,andsoon,shouldalsobecountedintoconsideration.Inaddition,suchasprice,so3.2.3
Other
InitiatingAbilityThermal-initiatedpolymerizationMonomerscanpolymerizeunderthefunctionofheat,withoutinitiator,whichiscalledthermal-initiatedpolymerization,orforshort,thermalpolymerization.Photo-initiatedpolymerizationUnderlightirradiation,manyolefinicmonomerscanproducefreeradicals,whichcaninitiatepolymerization.Wecallthislightinitiatedpolymerization.Highenergyradiationinitiatedpolymerization3.2.3OtherInitiatingAbility(1)
Thermal-InitiatedPolymerizationStyreneisusedmosttostudythemechanismofthermalpolymerizationTherateofinitiationis
(1)Thermal-InitiatedPolymeriStyreneThermalPolymerizationIftheconversionofstyrenethermalpolymerizationreaches50percent400daysareneededat29℃.235minutesareneededat127℃.Only16minutesareneededat167℃.StyreneThermalPolymerization(2)Photo-InitiatedPolymerizationLightquantumenergy
Planckconstant
ThespeedoflightThefrequencyoflight
ThewavelengthoflightPhoto-initiatedpolymerizationcanbedivideintodirectlightinitiatedpolymerizationandphotosensitivepolymerization.(2)Photo-InitiatedPolyme①DirectLightInitiatedPolymerization
LightquantumMonomermoleculeExcitedst
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