高分子物理復(fù)旦大學(xué)高分子的聚合狀態(tài)ppt課件

1、Chapter 5 Condensed States of Polymers5.1 Polymer Melts and Glasses5.2 Crystalline States of Polymers5.3 Oriented States of Polymers5.2.1 Chain Conformations in Crystals5.2.2 Basic Morphology of Polymer Crystals5.2.3 Polymer Crystallization Models、Thermodynamics、Kinetics5.4 Liquid Crystalline Polyme

2、rs5.1 Polymer Melts and Glasses The deepest and most interesting unsolved problem in solid state theory is probably the theory of the nature of glass and the glass transition. (Anderson, P.W. Science 2019, 267, 1615.) (liquid)liquidglasses(glasses)slowly cooledfast cooledTg fastslow TgGT The transit

3、ion from melt to glass is called glass transition (玻璃化轉(zhuǎn)變玻璃化轉(zhuǎn)變) Tg: glass transition temperature (玻璃化轉(zhuǎn)變溫度玻璃化轉(zhuǎn)變溫度)Glass Transition as a Relaxation Process Thermal history dependence of TgliquidVcrystalglass 2glass 11: fast cooling2: slow coolingsupercooled liquidTTmTg1Tg2Temperature dependence of the

4、specific volume of PVA, measured during heating. Dilatometric (膨脹計(jì)法膨脹計(jì)法) results obtained after a quench to 20 C, followed by 0.02 or 100 h of storage. (Kovacs, A. J. Fortschr. Hochpolym. Forsch. 1966, 3, 394)5.2 Polymer Crystallization Requisites for polymer crystallization Chemical regularity Homo

5、polymer Copolymerblock copolymerrandom copolymer Stereoregularity (立構(gòu)規(guī)整度立構(gòu)規(guī)整度) Isotactic (等規(guī)等規(guī)) Syndiotactic (間規(guī)間規(guī)) Atactic (無規(guī)無規(guī))5.2.1 Chain Conformations in Crystals21314161525142= 2162= 317172739291838132 31H31Helix ConformationsZig-zag ConformationsH21Hydrogen bondingsyndiotacticisotactic323CHCH

6、CHCHCHrepeating unitWhy Helix ?HH0.25 nmPE0.12 nmPPCH3: 0.2 nm Chain packing in crystal latticesLHRHLHLHLHLHRHRHRH Chain packing in crystal latticesPEorthorhombictriclinicHydrogen bondingTrigonali-Poly-1-buteneMonoclinic5.2.2 Basic Morphology of Polymer Crystals Crystal Habits: a: lamellar (薄片狀薄片狀)

7、b: platy c: tabular d: isometric e: prismatic f: acicular g: needle-like h: fibrous (纖維狀纖維狀) “Single crystals have one lattice Macromolecular crystals are often lamellar or fibrous. “Polycrystalline samples are aggregates of many single crystalsLamellae Crystallized from Dilute Solution Polyethylene

8、 (聚乙烯聚乙烯)Tc 70 CTc 80 COrientations of polymer chains in lamellaePE chains must be folded back and forth within the lamella!Note: the lamellar thickness is 10 nm, the chain length is 1000 nm.PE chains are perpendicular to the lamellar surface. Polyoxymethylene (聚甲醛聚甲醛) PEO(聚氧乙烯聚氧乙烯)-b-PS(聚苯乙烯聚苯乙烯) d

9、iblock copolymerLamellae Crystallized from Melt Spherulites (球晶球晶) of polymersUnder Polarized optical microscopy Lamellae in a spherulite Lamellae Tie Molecules AmorphousThe mechanism of Maltese cross extinction patternQE OP: PolarizerOA: AnalyzerQE: Vector of polarized lightI0QRQT projectingon OAOP

10、 QM QN2QNQMI Theoretical analysis of Maltese cross extinction pattern0QEi tE e 02222sin 2 sQNMin2QIE 0QRsinitEe0QTcosi tEe projectingon OA0QMsincositEe 0QNcos sini tEe00200sin2sincos2sin22sin2sincossin2sinsincos2QNQMcossi2222212n1ii ti ti ti tEeEeEeeeiiEi / positive spherulite negative spherulitennn

11、nnnRelations of POM and SALS (small angle light scattering)M/nEnEE n nn nM 2IM OA POMSALS22222/2coscos2sin 2E nn OAnE nnE nn OAnn OAnnnnn diSM OA e q rqr *I qS q SqSALS patterns of spherulitesVvHvqmax1/R5.2.3 Polymer Crystallization How do the polymer chains pack in the lamellar crystals?Random coil

12、 with the chain contour length (輪廓長度輪廓長度) longer than 1 mmLamella with the thickness of 5-50 nm and lateral size of microns. Crystallization Macroconformations (巨構(gòu)象巨構(gòu)象):Extended chains(伸展鏈伸展鏈)Folded chains(折疊鏈折疊鏈)Random coils(無規(guī)線團(tuán)無規(guī)線團(tuán))Fringed micelle(纓狀微束纓狀微束)Chain-Folded Lamellae of PolymersRandom

13、coilCrystallizationTC or DT Chain folding (鏈折疊鏈折疊) conceptChain-folded LamellaeseseFolded chain (折疊鏈折疊鏈)Fold surface(折疊外表折疊外表)s sLateral surface(側(cè)外表側(cè)外表)TC: crystallization temperature (結(jié)晶溫度結(jié)晶溫度)DT: supercooling (過冷度過冷度), DT = Tm0 - TCse: fold surface free energy (折疊外表自在能折疊外表自在能)s: lateral surface fr

14、ee energy (側(cè)外表自在能側(cè)外表自在能), se 10slLamellar thickness or fold length (片晶片晶厚度厚度) Process of Polymer CrystallizationTwo steps: 1. Nucleation (成核成核) processSizeDGDG0embryosuper critic. sizestablecritical nucleusDG Gcrysta DG Gcrysta Gmet , DG DH Gmet , DG DH TDSTDSGcrysta Gbuk SAsGcrysta Gbuk SAsDG Gbuk

15、Gmet SAs DGf DG Gbuk Gmet SAs DGf SAsSAsA is the suface area an DGf is A is the suface area an DGf is the buk free energy change.the buk free energy change.abcSchematic representation of the change in free energy as a function of size illustrating the nucleation processTypes of crystal nuclei. (a) p

16、rimary (初次初次), (b) secondary (二次二次), (c) tertiary (三次三次) nucleus. Homogeneous (均相均相) and heterogeneous (異相異相) nucleationEstimate the critical nucleus size*44eemffTlghTssDDDefaalglaGss2224DD0fmfmfgThTsDDD For primary nucleus For secondary nucleus*22eemffTlghTssDDDefalgalaGss442DDsagalGf42DDfgaDs4*feg

17、lDs4*mffThsDD22feGabl gblabssD D2*mfTahTsDD4*mfTahTsDD0GaD0GlD ffmfcfcffmhsTTgThTshTDDDD DD D2. Linear Growth of Polymer Crystallization Temperature dependence of linear growth rate (線生長速度線生長速度)Temperature dependence of the radial growth rate u of spherulites in isotactic polystyrene (left), polyami

18、d 6 (center) and poly(tetramethl-p-silpheylene siloxane) (right). Tf: equilibrium melting temperature. Surface nucleation on substrate with length L with a rate i Linear growth rate G: the growth rate of crystal perpendicular to the substratel: fold length; a: width of stem; b: thickness of the stem

19、; g: substrate completion rateOverall Polymer Crystallization Rate Overall crystallization rate (總結(jié)晶速度總結(jié)晶速度)Tm0TgTMAXOverall rateBell curve of overall crystallization rateTotal volume or density: or Crystallinity: or 1(1) or 1 oracaaccacccccccccacacccaaacaacWWWVVVWVwvWVwwvvvvwvvrrrrrrrrrrrrrrrr rr u

20、sually 0.70.2cacacvwrrrrwc: weight fraction; vc: volume fractionW: weights: density (g/cm3): specific volume (cm3/g)1/ Definition of crystallinity (結(jié)晶度結(jié)晶度)wc Wc/Wtotal; vc Vc/VtotalTimeCrystallinityIsothermal crystallizationT1T2T3t1/2IIIIIIIVOverall Crystallization KineticsnAvrami equation0nkttvvevv

21、0lnlnlnln 1lnlnctvvvvvntkh0h00011tcathhvvhhhhhh 1/2tt1/21/2ln2nktlnt0lnlntvvvvhtht1/tttvhrDilatometric (膨脹計(jì)法膨脹計(jì)法)Kinetics models of overall crystallizationn1. Free growth modelRvt 3crystaltotal43icVVvNvtVVb. new nucleus produced - homogeneousa. constant numbers of nucleus- heterogeneoustDttDtt tDtDt

22、3*3 403*043334d/tctvIv tIIvvtttttttDt3* 3 4IttvtttDI* nucleation rate*33*340430 +4.3.3iIv tItv ttIvtttttDDDtPoissons raindrop problemIf raindrops fall randomly on a pond creating expanding circular waves, what is the chance that the number of waves created by different raindrops which pass over a re

23、presentative point P up to time t is exactly n?Kinetics models of overall crystallization-Avramin2.Impingement modelP solution: / !EnnP teEnPoisson distributionWhat is the chance that no wave reaches a given point P in space ?1cv 01EcPev iV tE tVheterogeneoushomogeneous 34/31Nvtcve*3 4/31cIv tveThe

24、Avrami equation for 3DE(t): wave spreading area during tWhile t or v is very small cvE t1xex *3 4/3Iv t343NvtorThermodynamics of Crystallization: 1. Melting point of Lamellar CrystalsThermodynamics of Crystallization: 1. Melting point of Lamellar Crystals000fmfmfgThTsDDD0mT0ffmhsTDD021emmTTl hsDMelt

25、ing data for lamellar polyethylene grown from the melt and from solutionTm = 414.2(1-0.627/l)Lauritzen-Hoffman equation002emmmTlh TTsDSimilar to critical nucleus size Gibbs-Thomson extrapolation2224feGa l gaalssD D0 GDmTla00fmfmfmmfmgThTsTThTD DD DThermodynamics of Crystallization: 2. Melting point

26、of Polymer mixtureChemical Potential of Polymer in amorphous phase2022212ln11RTxxmmffcfConsider a system of Polymer/Impurity mixture:Chemical Potential of one monomer unit of polymer in amorphous phasePolymer is compatible with impurity but cant co-crystallize with impurity00uCuuuImmmm20212ln111uuRT

27、xxfmmfcfEffects of “Impurities on TmCondition of Phase Equilibrium00uICuuummmmSuperscript of C: Crystalline Phase0uCuuuumGHTSmm DDD00ummmmuHSTHTSDDDD02212ln111IuuRTxxmmffcf22120ln1111mumRTTHxxTffcfD02212ln11111mmuTTHRxxffcfDSuperscript of I: Amorphous Phase01mumTHT DEffects of “Impurities on Tm22120

28、ln11111mmuRTTHxxffcf DFor x2, x1=1211011mmuRTTHfcf DFor end-group effects: 1=2/N, =00112mmuRTTHNDFor copolymer011lnmmuRPTTH Dalternating copolymer: PXA1P: Probability of crystalline unit with sequential connection 2221111211ln22uuRRHHfffcff DD211121ln 1ln2ffffNote:For polymer blends220111mmuRTTHcf D

29、22120212ln11111mmuRTTHxxxffcf Dpolymer/small moleculepolymer/polymer3. Effects of Chain Structure on TmmmmHTSDD1) Symmetry and Asymmetry2) Flexible and Rigid3) Molecular Interaction5.3 Oriented States of PolymersnDefinitionn nApplicationsn Fiber, BOPP, BOPET, BOPE, nOrientation function213 cos12F fu

30、lly orientedfully disorder10perpendicular011/30F10-1/2: 0180: 0180one or two dimensional order5.4 Liquid Crystalline Polymers “Liquid crystals stand between the isotropic liquid phase and the strongly organized solid state. Life stands between complete disorder, which is death, and complete rigidity

31、, which is death again. Dervichian D. G. Mol. Cryst. Liq. Cryst. 1977, 40, 19. States of matter:Solids, liquids, and gases“Liquid crystals (LCs) represent a number of different states of matter in which the degree of molecular order lies intermediate between the perfect long-range positional and ori

32、entational order found in crystalline solid and the statistical long-range disorder found in an isotropic liquid. Phenomenologically, LCs exhibit both solid-like anisotropic features and liquid-like fluidity. On the basis of these characteristics, the term “mesomorphic phases or “mesophases, may be

33、a more appropriate name than liquid crystals.What are Liquid Crystals Anisotropic molecular shape of liquid crystals Rod-like or ellipsoid-likeSpace filling model of molecule 7S5 Plate-like or disk-like Lyotropic liquid crystals (溶致型液晶溶致型液晶):The liquid crystal phase is dependent on the concentration

34、 of one component in another. Thermotropic liquid crystals (熱致型液晶熱致型液晶):The liquid crystal phases of pure substance are caused by temperature change.Nematic Phase (向列相向列相) Director NLong-range orientational order of moleculesMoleculesNnnnnnnn Molecular arrangement in a nematic phasePolydomain struct

35、ure in a nematic phase. Local directors are represented by n, and the global director is represented by N.Smectic Phases (近晶相近晶相)Director NLayersMolecules Layer structure in smectic phasesSmectic ASmectic CTilt AngleDirector N LayersMoleculesLiquid Crystal Phase of Chiral MoleculesStructure of chira

36、l smectic or smectic C* phase. The planes represent the smectic layers. The director always makes the same angle with the smectic planes, but the orientation of the director rotates about the line perpendicular to the planes in going from one layer to the next. Cholesteric phase (膽甾相膽甾相) (chiral (手性

37、手性) nematic phase) Chiral smectic phaseMolecules in the cholesteric phase. The director n rotates in a helical fashion. Because no physical quantities depend on the sign of n, the physical pitch of the cholesteric phase is P = p/k0 rather than 2p/k0.Cholesterol nonanoate molecule:Lyotropic liquid crystals: 1) surfactants or amphiphilic block copolymersLyotropic liquid crystals:2) rigid-rod