高分子化學(xué)浙江大學(xué)polymer1Introduction課件

1PolymerChemistry高分子化學(xué)Welcometo2ContentPolymeranditsstructureMechanismofpolymerizationreactionsProcessofpolymerizationThereactionsofpolymer3ScheduleChapter1Introduction 3hrChapter2RadicalPolymerization 12Chapter3RadicalCopolymerization 6Chapter4PolymerizationProcess 35IntroductionChapterI61.FundamentalConcepts71.1Whatisapolymer?Apolymerisalargemoleculecomprisedofrepeatingstructuralunitsjoinedbycovalentlybonds.

(Hermann.Staudinger,1924)

PolycomesfromtheGreekwordfor"many"andmercomesfromtheGreekwordfor"parts“.9Notethatallthreerepresentationsareequivalent.Oneusuallychoosestherepresentationthatemphasizesthemonomer(單體)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殼聚糖甲殼素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

(合成橡膠和彈性體)18Syntheticfibers(合成纖維)

Kevlar

Vest19Finepolymers(精細(xì)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.交替嵌段無規(guī)接枝291.5PolymerDisciplinesPolymersciencePolymerchemistryPolymerphysicsPolymerprocessPolymermaterialPolymerizationengineering30PolymerChemistry

ContentPolymeranditsstructurePolymerizationmechanismandkineticsPolymerreactionFrontier

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

Athermosetting(熱固性)plastic,orthermoset,solidifiesor"sets"irreversiblywhenheated.Elastomers(彈性體)arerubberypolymersthatcanbestretchedeasilytoseveraltimestheirunstretchedlengthandwhichrapidlyreturntotheiroriginaldimensionswhentheappliedstressisreleased.Moleculesinathermoplastic(熱塑性）areheldtogetherbyrelativelyweakintermolecularforces,sothatthematerialsoftenswhenexposedtoheatandthenreturnstoitsoriginalconditionwhencooled無定形結(jié)晶35C:ChemicalCompositionCarbon-chainpolymer–backbonecomposedofcarbonatomHeterochainpolymer–composedofbothcarbonandotheratoms,e.g.O,N,S,Petc.Elementpolymer–nocarboninbackbone36CarbonchainPolymer(碳鏈高分子)Vinylpolymersa.Polyolefin(聚烯烴):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(聚異戊二烯),

37Heterochainpolymer(雜鏈高分子)Polyamide/Nylon(聚酰胺),Polyurethane(聚氨酯)Polyurea(聚脲)Polysulfone(聚砜),Phenolic(酚醛),Ureas(脲醛)聚酯聚醚聚酰亞胺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-丙烯無規(guī)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)聚對苯二甲酸乙二醇酯42C

Accordingtothemonomeremployed

phenol-formaldehyderesin酚醛樹脂(苯酚+甲醛) epoxyresin

環(huán)氧樹脂(雙酚A+環(huán)氧氯丙烷)D.IUPACsystem

poly(oxyethylene)poly(ethyleneoxide) polymethylenepolyethylene43E

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

PolymerhasthesameatomsastheirmonomersCondensationpolymerization（縮合聚合）

polymerhasfeweratomsintherepeatunit(i.e.,somesmallmoleculewasemittedduringpolymerization).46

CondensationorAddition?473.2Chain(連鎖)vsStep(逐步)

PolymerizationreactionsarecharacterizedaccordingtoitsmechanismChainpolymerization（連鎖聚合）

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(開環(huán)聚合)Ring-openingMetathesispolymerization(開環(huán)異位聚合)GrouptransferPolymerization(基團(tuán)轉(zhuǎn)移聚合)533.3Homogeneousvsheterogeneousbulk(本體)solution(溶液)emulsion

(乳液)dispersion

(分散)precipitation

(沉淀)suspension

(懸浮)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,多分散性指數(shù)),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（立構(gòu)規(guī)整性）

Topology（拓樸結(jié)構(gòu)）5.1ChainStructureisotacticsyndiotacticcistranshead-headhead-tail625.2Conformation(構(gòu)象)randomcoilrigidrodhelicalhexagonal635.3AggregationMorphology(聚集態(tài)結(jié)構(gòu))Mostsmallmoleculebehaviorcanbeunderstoodintermsofthreestates:gas,liquid,andsolid.Polymersarelargemoleculeswithstrongintermolecularforceandtangledchains,anddonothaveavaporphase.Thelengthofpolymermoleculesalsomakesitdifficultforthelargecrystalsfoundinthesolidphasesofmostsmallmoleculestoform.Insteadsolidpolymerscanbemodeledintermsoftwophases-crystallineandamorphous.Thusthebehaviorofpolymerscanbetterbeunderstoodintermofthethreephases:melt(熔融),crystalline(結(jié)晶),andamorphous(無定形)64Crystalline

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

(無定型)

Amorphouspolymersaresofter,andarepenetratedmorebysolventsthanaretheircrystallinecounterparts.Polymerchainswithbranchesorirregularpendantgroupscannotpacktogetherregularlyenoughtoformcrystals.Thesepolymersaresaidtobeamorphous.

66Semi-crystalline

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

Tensilestrength,Impactresistant,etcProcessingproperties:meltviscosity

Thermalstability:Tg,Tm,TcFlameresistanceChemicalresistanceDegradabilityOthers71TensileStrength(拉伸強(qiáng)度)stressneededtobreakasample72%ElongationtoBreak(斷裂伸長率)

Fibershavealowelongation-to-breakandelastomershaveahighelongation-to-breakstrainonasamplewhenitbreaks73Young‘sModulus(楊氏模量)Rigidmaterials,suchasmetals,haveahighYoung'smodulus.Ingeneral,fibershavehighYoung'smodulusvalues,elastomershavelowvalues,andplasticsliesomewhereinbetweenYoung'smodulusistheratioofstresstostrain.Italsoiscalledthemodulusofelasticityorthetensilemodulus74Toughness(韌性)Thereisadifferencebetweentoughnessandstrength,asisillustratedinthethreeplots.Thetoughnessisameasureoftheenergyasamplecanabsorbbeforeitbreaks75TheGlassTransition(玻璃化轉(zhuǎn)變)Atalowtemperaturetheamorphousregionsofapolymerareintheglassystate.Inthisstatethemoleculesarefrozenonplace.Theymaybeabletovibrateslightly,butdonothaveanysegmentalmotioninwhichportionsofthemoleculewigglearound.Intheglassystate,themotionoftheredmoleculeintheschematicdiagramattherightwouldNOToccur.Whentheamorphousregionsofapolymerareintheglassystate,itgenerallywillbehard,rigid,andbrittle.76MeltingPoint(熔點(diǎn))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請說出以下幾個(gè)概念的異同： 聚合物、高分子、大分子請說出“鳥巢”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.歷史和現(xiàn)狀19世紀(jì)：天然高分子的改性1832年--天然橡膠硫化改性（交聯(lián)），使橡膠不發(fā)粘、有高彈性，成為重要的材料；1868年--制成硝化纖維塑料（賽璐珞）；1892年--制成粘膠纖維（天然纖維再生制成的人造纖維）；2