高分子化学浙江大学polymer1Introduction课件

1PolymerChemistry高分子化学Welcometo2ContentPolymeranditsstructureMechanismofpolymerizationreactionsProcessofpolymerizationThereactionsofpolymer3ScheduleChapter1Introduction 3hrChapter2RadicalPolymerization 12Chapter3RadicalCopolymerization 6Chapter4PolymerizationProcess 35IntroductionChapterI61.FundamentalConcepts71.1Whatisapolymer?Apolymerisalargemoleculecomprisedofrepeatingstructuralunitsjoinedbycovalentlybonds.

(Hermann.Staudinger,1924)

PolycomesfromtheGreekwordfor"many"andmercomesfromtheGreekwordfor"parts“.9Notethatallthreerepresentationsareequivalent.Oneusuallychoosestherepresentationthatemphasizesthemonomer(单体)fromwhichthepolymerwasmade.Thereareendgroupsonthechainthataredifferentfromtherepeatunits,buttheseusuallyrepresentanegligibleportionofthemolecule,sotheyareseldomdrawn.degreeofpolymerization聚合度10Polymer(聚合物)vsMacromolecule(大分子)Macromolecule

moleculewithhighmoleculeweightPolymer

moleculecomprisedofrepeatingunitSamplepolymer

macromolecule

Polyethylene

DNAProtein

111.2FlowchartofPolymericMaterials

InorganicNaturalClaysBricksCementPotterySandsGlassSyntheticFibersOrganicNaturalPolysaccharidesProteins

PolyisopreneSyntheticPlasticsFibersRubbersAdhesiveCoatings…13Cellulose,Starch,DNA,ProteinInNature壳聚糖甲壳素14SyntheticMaterials

AnnualProductionofPolymerMaterials(millionton)Year 1970 1980 19902000 Plastics 27 53 107 175(11*)Syntheticfiber 4.9 12 24 35 (6.4)Syntheticrubber 5.5 13 23 44 (0.9)Total 38 78 154 254*China15GeneralPlastics(通用塑料)17Syntheticrubber,elastomer

(合成橡胶和弹性体)18Syntheticfibers(合成纤维)

Kevlar

Vest19Finepolymers(精细高分子)21PlasticsvsSteel22EnergyConsumption

23Greenornot?polyolefinIdealmaterialpaperglassaluminium25Polymersarelargemolecules.Fortunately,theyarenotrandomcollectionsofatoms;ifthiswerethecase,theywouldbeimpossibletostudy.Polymersarebuiltupfromsmallermolecules(monomers),andthereforepossessacharacteristicchainstructure

consistingofmultiplerepeatunitsthatarerelatedchemicallyTherepeatunitscanallbeidentical,inwhichcasethecompoundisahomopolymer(均聚物).26Iftherepeatunitsaredifferent,theresultisacopolymer(共聚物).

Consideracopolymermadefromjusttwoingredients:thetwocanbesequencedalongthebackboneinvariousmodes.交替嵌段无规接枝291.5PolymerDisciplinesPolymersciencePolymerchemistryPolymerphysicsPolymerprocessPolymermaterialPolymerizationengineering30PolymerChemistry

ContentPolymeranditsstructurePolymerizationmechanismandkineticsPolymerreactionFrontier

NovelsyntheticmethodandpolymerfamilyDesignandcontrolonthechainstructureofpolymerRecycleofpolymer312.CategoriesandNomenclatureofPolymer322.1ClassificationRulesThereisnouniformsystemofclassificationofpolymers.Theterminologyhasevolvedalongwithpolymerscience,andtherearenumerousexceptionstocategories.Thewaypeopleclassifypolymersdependstheirexperience.Widelyusedhistoricaltermsortradenameslackinginformationcontent.33A:ApplicationPlasticsFibersRubbersCoatingsAdhensivesIndustryPolymerFunctionalGeneralFine34B.Processability

Athermosetting(热固性)plastic,orthermoset,solidifiesor"sets"irreversiblywhenheated.Elastomers(弹性体)arerubberypolymersthatcanbestretchedeasilytoseveraltimestheirunstretchedlengthandwhichrapidlyreturntotheiroriginaldimensionswhentheappliedstressisreleased.Moleculesinathermoplastic(热塑性）areheldtogetherbyrelativelyweakintermolecularforces,sothatthematerialsoftenswhenexposedtoheatandthenreturnstoitsoriginalconditionwhencooled无定形结晶35C:ChemicalCompositionCarbon-chainpolymer–backbonecomposedofcarbonatomHeterochainpolymer–composedofbothcarbonandotheratoms,e.g.O,N,S,Petc.Elementpolymer–nocarboninbackbone36CarbonchainPolymer(碳链高分子)Vinylpolymersa.Polyolefin(聚烯烃):polymerderivedfromalkenePolyethylene(聚乙烯),polypropylene(聚丙烯),etcb.Polystyrene:PS(聚苯乙烯,1839byEduardSimon)anditsfamilies(ABS，SBS，SBR)；c.Polyvinylchloride：PVC(聚氯乙烯,1872byEugenBaumann)anditscopolymers,d.Acrylicpolymers:PMMA(聚甲基丙烯酸甲酯),PA(聚丙烯酸),;f.Polydiene:syntheticrubber,PBd(聚丁二烯),PIp(聚异戊二烯),

37Heterochainpolymer(杂链高分子)Polyamide/Nylon(聚酰胺),Polyurethane(聚氨酯)Polyurea(聚脲)Polysulfone(聚砜),Phenolic(酚醛),Ureas(脲醛)聚酯聚醚聚酰亚胺38Elementchainpolymer(元素高分子)Polysilicone392.2NomenclaturePolymernomenclatureiscomplicatedforavarietyofreasons:Mostpolymernamesarebasedonthenamesofmonomer(source-basedsystem)IUPACsystemisnotwidelyusedSomepolymerstructuresaresocomplicated:branchingorcrosslinking;Polymersciencehassomefairlysharpdefinedboundaries:rubberchemistvsplasticchemist;Describepolymerbasedonitscharacteristics40A.Accordingtothenameofmonomer----vinylpolymers

Homopolymer:poly(monomer)

polystyrene,PS;

poly(methylmethacrylate),PMMA

Copolymer:poly(monomer-co-monomer) poly(ethylene-co-propylene),乙烯-丙烯共聚物

poly(ethylene-r-propylene),乙烯-丙烯无规共聚物

poly(ethylene-b-propylene),乙烯-丙烯嵌段共聚物

poly(ethylene-g-propylene),乙烯-丙烯接枝共聚物

poly(ethylene-a-styrene),乙烯-苯乙烯交替共聚物

41B.

Accordingtothefunctionalgroupintherepeatunit(condensationpolymer) Polyester;polyether,polyamidepoly(hexamethyleneadipamide)

(聚己二酰己二胺)Poly(ethyleneterephthalate)聚对苯二甲酸乙二醇酯42C

Accordingtothemonomeremployed

phenol-formaldehyderesin酚醛树脂(苯酚+甲醛) epoxyresin

环氧树脂(双酚A+环氧氯丙烷)D.IUPACsystem

poly(oxyethylene)poly(ethyleneoxide) polymethylenepolyethylene43E

SlangandTradeNamesTheseslangnamesoftencontainvestigesofthechemicaldescriptionofthepolymer,butshortenedorcorrupted.Thetradenameshaveshort,snappy-soundingnamesthatcouldbeeasilyrememberedandspelledbytheircustomers. Nylon6polycaprolactam(聚己内酰胺) EPRethylene-propylenerubberFAbbreviations LDPElowdensitypolyethylene PVCpolyvinylchloride PETpoly(ethyleneterephthalate)443.PolymerizationReaction453.1Condensation(缩合)vs.Addition(加成)Carothersoriginallyclassifiedpolymersbasedonacomparisonoftheatomsinthemonomertotheatomsintherepeatunit.Additionpolymerization（加成聚合）

PolymerhasthesameatomsastheirmonomersCondensationpolymerization（缩合聚合）

polymerhasfeweratomsintherepeatunit(i.e.,somesmallmoleculewasemittedduringpolymerization).46

CondensationorAddition?473.2Chain(连锁)vsStep(逐步)

PolymerizationreactionsarecharacterizedaccordingtoitsmechanismChainpolymerization（连锁聚合）

Themolecularweightincreasesbythesuccessiveandfastlinkingofmonomermoleculestotheendofagrowingchain.StepPolymerization（逐步聚合）

Polymerchainarebuiltupinastepwisefashionbytherandomunionofmonomermoleculestoformdimers,trimersandhigherspeciesthroughoutthemonomermatrix48ComparisonbetweenChainandStepPolymerizationChain

Stepmonomerpolymer49DifferencesbetweenChainandStepPolymerizationGrowthoccursonlybyadditionofmonomertoactivechainend.Monomerispresentthroughout,butitsconcentrationdecreases.Polymerbeginstoformimmediately.Chaingrowthisusuallyveryrapid(secondtomicroseconds).MWandyielddependonmechanismdetails.Onlymonomerandpolymerarepresentduringreaction.Usually(butnotalways)polymerrepeatunithasthesameatomsashadthemonomerAnytwomolecularspeciescanreact.Monomerdisappearsearly.PolymerMWrisesslowly.Growthofchainsisusuallyslow(minutestodays).LongreactiontimesincreaseMW,butyieldofpolymerhardlychanges.Allmolecularspeciesarepresentthroughout.Usually(butnotalways)polymerrepeatunithasfeweratomsthanhadthemonomer.ChainStep50VariationofConversionandMWStepchaintime

conversion(%)timestepchainMn51Therearefartoomanyexceptions.Steppolymerizationbyadditionofalcoholstodiisocyanatestoformpolyurethanes:Chainpolymerization(ringopeningofheterocycle)withlossofCO2toformpolypeptide.52Otherterminologies

Ring-openingpolymerization(开环聚合)Ring-openingMetathesispolymerization(开环异位聚合)GrouptransferPolymerization(基团转移聚合)533.3Homogeneousvsheterogeneousbulk(本体)solution(溶液)emulsion

(乳液)dispersion

(分散)precipitation

(沉淀)suspension

(悬浮)surface

(表面)solidstate

(固相)544.MolecularWeightandMolecularWeightDistribution554.1MolecularWeightDistribution(分子量分布)Becauseallpolymersaremixturesofmanylargemolecules(polydispersity),onemustresorttoaveragestodescribemolecularweight.564.2AverageMolecularWeight(平均分子量)Amongmanypossiblewaysofreportingaverages,fourarecommonlyused:ViscosityAverage

ZAverageNumberAverageWeightAverageMηMz>Mw>Mη>MnAverage57Theweightaverageisprobablythemostuseful,becauseitfairlyaccountsforthecontributionsofdifferentsizedchainstotheoverallbehaviorofthepolymer,andcorrelatesbestwithmostofthephysicalpropertiesofinterest,e.g.meltviscosity.TheratioofMwtoMnisknownasthepolydispersityindex(PDI,多分散性指数),andprovidesaroughindicationofthebreadthofthedistribution.ThePDIapproaches1.0(thelowerlimit)forspecialpolymerswithverynarrowMWdistributions,but,fortypicalcommercialpolymers,istypicallygreaterthan2(occasionallymuchgreater).58Smallmoleculeshavesmallvaluesthereisasharpriseinpropertiesasthechainsgrowtointermediatesizethepropertiesleveloffasthechainsbecomelongenoughtobetruepolymers4.3DependenceofPolymerPropertiesonMW59Manypolymerpropertiesofinterest(Tg,modulus,tensilestrength,etc.)followapeculiarpatternwithincreasingMW.Thegoalofpolymersynthesisisnottomakethelargestpossiblemolecules,butrather,tomakemoleculeslargeenoughtogetontotheplateauregion.Afewpropertiesaredictatedbytherepeatunitsalone,andthereforethesearenotchangedmuchbyMW.Examples:color,dielectricconstant,andrefractiveindex.605.PolymerStructure61StructureunitMonomersequence

-AABBBABABBABB--AAAAABBBBBBBB-Stereoregularity（立构规整性）

Topology（拓朴结构）5.1ChainStructureisotacticsyndiotacticcistranshead-headhead-tail625.2Conformation(构象)randomcoilrigidrodhelicalhexagonal635.3AggregationMorphology(聚集态结构)Mostsmallmoleculebehaviorcanbeunderstoodintermsofthreestates:gas,liquid,andsolid.Polymersarelargemoleculeswithstrongintermolecularforceandtangledchains,anddonothaveavaporphase.Thelengthofpolymermoleculesalsomakesitdifficultforthelargecrystalsfoundinthesolidphasesofmostsmallmoleculestoform.Insteadsolidpolymerscanbemodeledintermsoftwophases-crystallineandamorphous.Thusthebehaviorofpolymerscanbetterbeunderstoodintermofthethreephases:melt(熔融),crystalline(结晶),andamorphous(无定形)64Crystalline

Polymermoleculesareverylargesoitmightseemthattheycouldnotpacktogetherregularlyandformacrystal.Itnowisknownthatregularpolymersmayformlamellar(plate-like片晶)crystalswithathicknessof10to20nm.Whenamoltencrystallizablepolymercools,thecrystalsgrowfromindividualnucleiandradiateoutlikethespokesofabicyclewheel.Thecrystallineportionsactuallyradiateoutininthreedimensions,formingspheresthatarecalledspherulites（球晶）.65Amorphous

(无定型)

Amorphouspolymersaresofter,andarepenetratedmorebysolventsthanaretheircrystallinecounterparts.Polymerchainswithbranchesorirregularpendantgroupscannotpacktogetherregularlyenoughtoformcrystals.Thesepolymersaresaidtobeamorphous.

66Semi-crystalline

Semi-crystallinepolymershavebothcrystallineandamorphousregions.Semi-crystallinityisadesirablepropertyformostplasticsbecausetheycombinethestrengthofcrystallinepolymerswiththeflexibilityofamorphous.Semi-crystallinepolymerscanbetoughwithanabilitytobendwithoutbreakingIfwemodelapolymerashavingdistinctcrystallineandamorphousregions,thenthepercentageofthepolymerthatiscrystallineiscalledthepercentcrystallinity.Thepercentcrystallinityhasanimportantinfluenceonthepropertiesofthepolymer.67AggregationMorphology(聚集态形态)LiqidcrystallineOrientation68AggregationMorphologyBlendPS-b-PIp(PS-b-PnBA)nX共混物696.ImportantProperties70Mechanicalproperties:

Tensilestrength,Impactresistant,etcProcessingproperties:meltviscosity

Thermalstability:Tg,Tm,TcFlameresistanceChemicalresistanceDegradabilityOthers71TensileStrength(拉伸强度)stressneededtobreakasample72%ElongationtoBreak(断裂伸长率)

Fibershavealowelongation-to-breakandelastomershaveahighelongation-to-breakstrainonasamplewhenitbreaks73Young‘sModulus(杨氏模量)Rigidmaterials,suchasmetals,haveahighYoung'smodulus.Ingeneral,fibershavehighYoung'smodulusvalues,elastomershavelowvalues,andplasticsliesomewhereinbetweenYoung'smodulusistheratioofstresstostrain.Italsoiscalledthemodulusofelasticityorthetensilemodulus74Toughness(韧性)Thereisadifferencebetweentoughnessandstrength,asisillustratedinthethreeplots.Thetoughnessisameasureoftheenergyasamplecanabsorbbeforeitbreaks75TheGlassTransition(玻璃化转变)Atalowtemperaturetheamorphousregionsofapolymerareintheglassystate.Inthisstatethemoleculesarefrozenonplace.Theymaybeabletovibrateslightly,butdonothaveanysegmentalmotioninwhichportionsofthemoleculewigglearound.Intheglassystate,themotionoftheredmoleculeintheschematicdiagramattherightwouldNOToccur.Whentheamorphousregionsofapolymerareintheglassystate,itgenerallywillbehard,rigid,andbrittle.76MeltingPoint(熔点)Polymersdonothaveasinglewell-definedmeltingpoint.Whenapolymer"melts"itslowlybecomes"leathery,"then"tacky,"andthenliquidoverafairlybroadtemperaturerange.Thecrystallineportionofthepolymerisanonequilibriumdistributionofalargenumberofcrystallitesofdifferentsizesandindifferentenvironments.Theyalldonotmeltatexactlythesametemperature.77ComparisonbetweenglasstransitonandmeltingGlassTransitionPropertyoftheamorphousregionBelowTg:DisorderedamorphoussolidwithimmobilemoleculesAboveTg:DisorderedamorphoussolidinwhichportionsofmoleculescanwigglearoundAsecondordertransition(seebelow)MeltingPropertyofthecrystallineregionBelowTm:OrderedcrystallinesolidAboveTm:DisorderedmeltAfirst-ordertransition(seebelow)78StatetransitionTgTfTemperature

glasselasticDeformationviscoelastic79Highmolecularweightderivedfromsmallmolecules(MW:104-107）NoclearstandardinMWSmallmolecule－oligomer－polymerComplicatedchainstructure:monomersequence,topology,regiosequence,tacticitySpecialpropertiesdifferentfromsmallmoleculeSoftmaterialinadditiontogas,liquidandsolidSummery:CharacteristicsofPolymer80Discussion请说出以下几个概念的异同： 聚合物、高分子、大分子请说出“鸟巢”和“水立方”都采用了哪些高分子材料?81FamousPolymerChemists

———

NobelPrizeWinnersH.Staudinger(1953)

polymerchainformula.

K.Ziegler&G.Natta(1963)

Coordinationpolymerizationandstereoregularpolymers.

82P.Flory(1974)Polymerthermodynamics,kinetics,molecularweightdistribution,solutiontheory.B.Merrifield(1984)

Solidphasepolypeptidesynthesis.83DonaldJ.Cram;Jean-MarieLehn;CharlesJ.Pedersen(1987)fortheirdevelopmentanduseofmoleculeswithstructure-specificinteractionsofhighselectivity84P.DeGennes(1991)

Polymersolidstatetheoryandliquidcrystals.AlanHeeger,AlanMacDiarmid,andShirakawa(2000)Electricallyconductingandsemiconductingpolymers858.Historyandfuture86ModernHistory

FoundationsofchemistryVulcanizationofrubberdiscovered.Styrenepolymerized.ProductnotunderstoodVariousunsaturatedmonomerpolymerized.Isoprenefirstpolymerized;attempttomakerubber.

Studiesofnaturalmacromolecules.IndustrialproductionofphenolicresinChainstructurehypothesisgainsacceptance.Nylonandpolyestersynthesized.SyntheticrubberproducedforwareffortManypolymerpropertiesexplained.Successfulcommercializationofnumerouspolymers.Thermallystablepolymers,otherspecialmaterialsBiopolymeradvancesleadtoDNAtechnology.Polymersforhightechapplicationdeveloped.18001850190019502000871.历史和现状19世纪：天然高分子的改性1832年--天然橡胶硫化改性（交联），使橡胶不发粘、有高弹性，成为重要的材料；1868年--制成硝化纤维塑料（赛璐珞）；1892年--制成粘胶纤维（天然纤维再生制成的人造纤维）；2