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Polymer Physics高分子物理2 Aggregate Structure of Polymers高分子聚集态的结构高分子聚集态的结构高分子聚集态的结构高分子聚集态的结构12.1Introduction引言引言22.1.1 Concept of aggregate state 聚集态结构的内涵聚集态结构的内涵nAggregastestate Arrangement and stacking of different polymer chains.nAggregastestateincludesn晶态 Crystalline staten液晶态 Liquid crystalline staten非晶态 Amorphous staten取向态 Orientation state3高分子的结构高分子的结构Structure of Polymers链结构链结构Chain Structure聚集态结构聚集态结构Aggregate Structure织态结构织态结构Morphology晶态结构晶态结构Crystalline Structure无定型态结构无定型态结构Amorphous structure42.1.2Interactionsbetweenpolymermolecules高分子的分子间作用力高分子的分子间作用力 covalentbondinteractionnon-covalentbondvandeWallsforceHbond高分子由于分子间的相互作用而堆砌在一起高分子由于分子间的相互作用而堆砌在一起5nElectrostaticforce(静电力静电力):1.2 1042.1 104J/molnInductionforce(诱导力诱导力)：0.6 1041.2 104J/molnDispersionforce(色散力色散力)：0.08 1040.84 104J/mol偶极矩极化率电离能分子间距离vandeWallsforce6Total van de Walls force:28 kJ/molCC bond energy:347 kJ/molAssuming：PEsDP=104，Intermolecularinteractionforce:Ef2*104kJ/molCCbondenergy:EJ=347kJ/molEfEJWhen a single PE chain is pull out,2*104kJ/mol energy(van de Walls force)must be overcome，which can lead to breakage of C-C single bond.So,novaporstateforpolymer.7nInteractionforcebetweentheHatominXHbondandanotherYatomwithlargeelectronegavity.nElectronegativity：H:2.1O:3.5N:3.0F:4.0nStrength：1535kJ/molnFeatures：directivityandsaturabilityXHYHydrogenbond氢键氢键8H bondBond length(nm)Bond energy(kJ/mol)FHF0.2428OHO0.2718.8 34.3NHF0.2820.9NHO0.2916.7NHN0.315.44OHCl0.3116.3CHN13.7 18.292.1.3 Cohesive energy density高分子的内聚能密度高分子的内聚能密度nCohesiveenergy：The energy to remove 1 mol liquid or solid molecules out of the range of intermolecular interaction force.HV:摩尔蒸发热nCohesiveenergydensity：Cohesive energy in unit volume.HS:摩尔升华热(:摩尔体积)10Cohesive energy density of linear polymersPolymerPolymerNameNameCED(J/mCED(J/m3 3)PEPEPolyethylenePolyethylene259259PiBPiBPolyisobutylenePolyisobutylene272272NRNRNatural rubberNatural rubber280280BRBRButadiene rubberButadiene rubber276276SBRSBRStyrene-butadiene rubberStyrene-butadiene rubber276276PSPSPolystyrenePolystyrene305305PMMAPMMAPoly(methyl methacrylate)Poly(methyl methacrylate)347347PVAcPVAcPoly(vinyl acetate)Poly(vinyl acetate)368368PVCPVCPoly(vinyl chloride)Poly(vinyl chloride)381381PETPETPoly(ethylene terephthalate)Poly(ethylene terephthalate)477477Nylon66Nylon66Polyamide 66Polyamide 66774774PANPANPolyacrylonitrilePolyacrylonitrile992992RubberPlasticsFiber112.2TheCrystallineState高分子的晶态结构高分子的晶态结构12Differencebewteencrystallizationofpolymersandsmallmolecules:Polymer is not 100%crystalline!crystallinity(结晶度结晶度)：faction of crystalline phaseweight percentage crystallinityvolume percentage crystallinity131a2a2b3a3cABCdAB+BC=2dsinq q2dsinq q=nl lq q2.2.1 Methods of determining crystallinitywideangleX-raydiffraction(WAXD)X衍射14BraggequationDistance between successive identical planes of atoms in the crystal X-ray wavelength Angle between the x-ray beam and these atomic planes Any whole number 151617样品样品1819差式扫描量热法差式扫描量热法(DSC)Differential scanning calorimetry20(Xcw%)21(i)XcvMeasuredbydensity 22(ii)Xcw23Determination of DensityNi:number of ith atom in unit cellAi:atom mass of ith atom in unit cellVe:volume of unit cellNA:Avgadrov constant c is calculated from the density of unit cell of polymer crystal：24Notice：The values of crystallinity measured by different methods may have a large difference.Usually：XcWAXD()XcdensityXcDSC25262.2.2Unitcellandconformationofpolymerchainincrystalsspherulite fibrillar branching helical lamellae within fibrils1 mm(POM)1 m(AFM)500(AFM,TEM)crystal latticeindividual lamellar stacks1 (WAXD)100 (SAXS)27Unitcell(晶胞晶胞)：The smallest repeating unit of crystal structure with parallelepiped shapeCrystal systemLattice constantCubic 立方a=b=c;=90Hexagonal 六方a=bc;=90;=120Tetragonal 四方a=bc;=90Trigonal 三方a=bc;=90Orthorhombic 正交abc;=90Monoclinic 单斜abc;=90;90Triclinic 三斜abc;90abc高分子无此晶系c axis:polymer chain direction28Miller indices(h k l)abcc/2a/32b/3(1)intercept of crystalline plane in axes(2)removal of unit，getting reciprocal and reduction to common denominator(3)removal of denominator29a=2d200 30Selected crystallographic data PolymerCrystal SystemLattice ConstantNMolecular ConformationCrystal Density,g/cm3a,b,c,PolyethyleneOrthorhombic7.4174.9452.5472PZ211.00Monoclinic8.092.534.79107.92PZ210.998Polytetrafluoroethylene Pseudohexagonal5.595.5916.88119.31H1362.35Trigonal5.6619.501H1572.30Orthorhombic8.735.692.622PZ212.55Monoclinic9.505.052.62105.52PZ212.74it-PolypropyleneMonoclinic6.6520.966.5099.34H310.936Hexagonal19.086.499H310.922Trigonal6.386.331H310.939it-PolystyreneTrigonal21.906.656H311.13cis-1,4-PolyisopreneMonoclinic12.468.898.10924Z201.02PolyvinylchlorideOrthorhombic10.65.45.12PZ211.42PolytetrahydrofuranMonoclinic5.598.9012.07134.22PZ211.11Nylon 6Monoclinic9.5617.28.0167.54PZ211.23Monoclinic9.3316.884.781212H211.17Nylon 66Triclinic4.95.417.248.57763.51PZ101.24Triclinic4.98.017.29077672PZ101.248Nylon 610Triclinic4.955.422.44976.563.51PZ101.157Triclinic4.98.022.49077672PZ101.196Poly(ethylene terephthalate)Triclinic4.565.9410.7598.51121P1.45531n For polymer chains with no side group(PE)or with side group of small size(polyester，polyamide，POM，PVA).nPolymer chains adopt all-trans conformation.nThe lowest energy ofpolymer chains.nAdvantageous to dense packing in crystals.plane zigzag(平面锯齿结构平面锯齿结构)32PEOrthorhombic正交晶系正交晶系33UnitcellofPE:Orthorhombic,a=7.417,b=4.945,c=2.547NumberofCandHatomsinunitcell？Ve 9210-24cm3;NA=6.0231023mol-1 c 1.01 g/cm3 34The hydrogen-bonded structure of nylon 66.The unit cell face is shown dotted 35Helix(螺旋形结构螺旋形结构)For polymer chains with side group of large size,gauche conformation sometimes is adopted to reduce steric hinderance and free energy.ForexampleForexample：isotactic PP(Hisotactic PP(H3131),),poly(poly(o o-methyl styrene)(H-methyl styrene)(H4141),),isotactic PMMA(H isotactic PMMA(H5252)，isotactic isotactic poly(4-methyl pentene-1)(Hpoly(4-methyl pentene-1)(H7272),),poly(poly(mm-methyl styrene)(-methyl styrene)(H H11 811 8).).36IsotacticPPIsotacticPPThe polymer chains are not in the same plane,but The polymer chains are not in the same plane,but exhibit a helix conformation in the three-dimensioal exhibit a helix conformation in the three-dimensioal space.space.Every three repeating units forms a helix with a Every three repeating units forms a helix with a periodic length periodic length l l6.506.50.H H3131:H H：HelixHelix 3 3：number of repeating unitsnumber of repeating units 1 1：number of turns within a period number of turns within a period 37iPP(等规聚丙烯等规聚丙烯)：Monoclinic 单斜单斜382.2.3 Models of crystalline polymers高分子晶态结构模型高分子晶态结构模型The Fringed Micelle Model 缨状微束缨状微束Crystalline phaseAmorphous phase100Contour length=2000Bryant 1940 39Atactic PPIsotactic PPAl40nObservation：Both diffraction pattren and diffused circle are observed.The measured size of crystalline domain is about hundred astrongs(much smaller than the length of polymer chain)nModel：cocurrence of crystalline and amorphous domainssmall size of crystalline domain(one polymer chain can traverse several crystalline domains)random orientation of crystalline domainsnReasonable：The apparent density switchboard model fringed micelle modelEffectofcrystallizationconditions from dilute solution：100%adjacent re-entry from melt：70%adjacent re-entry quench：fringed micelleEffectofpolymermicrostructure homopolymer：adjacent re-entry or switchboard random copolymer：fringed micelle492.2.4 Morphology of polymer crystals 高分子晶体的形态高分子晶体的形态Lamellar-shaped single crystals 单晶50t聚乙烯的空心棱锥结构聚乙烯的空心棱锥结构51FormationofpolymersinglecrystalCrystallizeveryslowlyfromextremelydilutesolution(0.010.1%)(butsometimescanalsobeformedfromthemelt)AFM images of isotactic PS crystals in 11nm thick film in different Tc.210oC,4h205oC,4h200oC,4h52Dendritic crystal(树枝状晶树枝状晶)nHigher concentration(0.010.1%)，lower Tc.nDiffusion controlled.PEPEO53Polyethylene226C,4800atm,8hrCrystallinity=97%Density=0.993830000Highpressureandhightemperature.Themoststableinthermodynamic.Themoststableinthermodynamic.54Fibril Crystals 纤维状晶体In flow field,polymer chains extend and stack along flow direction.55String Crystals 串晶溶液低温，边结晶边搅拌。溶液低温，边结晶边搅拌。shish-kebabstructure56spherulite(球晶球晶)Polarized optical microscopy(偏光显微镜)57MalteseCross58Branchingspherulite of iPPSpheruliteFebrileLamellar59晶迭的形成晶迭的形成caLa amorphous c crystallineL long period606162nNegativespherulite：radial refractive index normal refractive index(small branching angle)63nConstantgrowthrateinradialdirectionnPolymerchainperpendiculartoradiusnMaltesecrossbyPOMnConsistinginfibrilsandstacksnCrystallinity100%nDiameterfrom0.1mmto1cmCharacteristicsofspherulite64Controlofspherulitesize(1)Crystallization rate:Tc or cooling rate(2)Microstructure:random copolymer(3)Nucleation agent:smaller size Having effects on transparency and mechanical properties65GrowthofspheruliteobservedbyPOM0s30s60s90s120s66banded spherulite(条带状球晶)67电镜观察的球晶结构Spherulite model and the Microscopy of PE spherulite 球晶模型及PE球晶的电镜照片68small angle laser light scattering 小角激光散射Radius of spheruliteWave lengthScattering angle correspondingto maximum scattering intensity69axialiteplatelet702.3Amorphousstate无定型态结构无定型态结构 712.3.1 About amorphous polymers 关于无定型高分子关于无定型高分子qTheamorphousstateisdefinedasacondensed,noncrystallinestateofmatter.qManypolymersareamorphousunderordinaryuseconditionsPolystyrenePoly(methylmethacrylate)Poly(vinylacetate)qCrystallinepolymersbecomeamorphousabovetheirmeltingtemperatures PolyethylenePolypropyleneNylon72GlassyLiquid flowRubbery plateauGlass transitionRubbery flowlgE,PaTemperatureTm657438910Amorphous polymersCrystalline polymersPhysical state of polymers 高分子的物理状态高分子的物理状态From amorphous phase73Questions of interest 感兴趣的问题感兴趣的问题qSolids or liquid?Water:liquid,disorderedCrystalline polymer:solid,ordered(regular)Amorphous polymer in glassy state:solid,disorderedqPossible residual order?On the simplest level,the structure of bulk amorphous polymers has been likened to a pot of spaghetti,where the spaghetti strands weave randomly in and out among each other Our knowledge of the amorphous state remains very incomplete,and that this and other areas of polymer science are the subjects of intensive research at this time 742.3.2 Major order-disorder arguments有序无序之争有序无序之争OrderDisorderConceptual difficulties in dense packing without orderRubber elasticity of polymer networksAppearance of nodules Absence of anomalous(异常)thermodynamic dilution effects Amorphous halos intensifying on equatorial plane during extension Radii of gyration the same in bulk as in-solventsNonzero Mooney-Rivlin C2 constantsFit of P()for random coil model to scattering dataElectron diffraction lateral order to 15-20Rayleigh-Brillouin scattering,x-ray diffraction,stress-optical coefficient,etc.studies showing only modest(if any)short-range order752.3.3 Models of amorphous polymers无定型高分子模型无定型高分子模型PrincipalsDescription of ModelH.MarkP.J.FloryRandom coil model;chains mutually penetrable and of the same dimension as in -solventsB.VollmertIndividual cell structure model,close-packed structure of individual chainsP.H.LindenmeyerHighly coiled or irregularly folded conformational model,limited chain interpenetrationT.G.F.SchoonPearl necklace model of spherical structural unitsV.A.KarginBundle model,aggregates of molecules exist in parallel alignmentW.PechholdMeander model,with defective bundle structure,with meander-like foldsG.S.Y.YehFolded-chain fringed-micellar grain model.Contains two elements:grain(ordered)domain of quasi-parallel chains,and intergrain region of randomly packed chainsV.P.PrivalkoY.S.LipatovConformation having folded structures with Rg equaling the unperturbed dimensionR.HosemannParacrystalline model with disorder within the lamellaeS.A.ArzhakovFolded fibril model,with folded chains perpendicular to fibrillar axis76Models of the amorphous state in pictorial form 无定型高分子模型图示无定型高分子模型图示Models increase in degree of order from(a)to(d).Florys random coil model无规线团Privalko and Lipatovs randomly folded chain conformations 无规折叠链Yehs folded-chain fringed-micellar model折叠链缨状微束Pechholds meander model 回纹波77Evidencesforrandomcoilmodel1.Absebce of anomalous effects for rubber elastic modulus and stress-temperature parameter when diluent is added.2.When radiate amouphous polymer in bulk and solution,the crosslinking degree is similar.3.The gyration radius in bulk and solution is similar(by SAXS and SANS)78Evidencesforfringedmicellarmodel1.For random coil:a/c链间的传播速度声波在完全未取向聚合物中的传播速度待测聚合物取向方向上的传播速度94Birefringenceanisotropicmethod双折射法双折射法952.4.4 Influence of Orientation to the Properties 取向对性能取向对性能的影响的影响Tensile ratio 20g/cm3xc%n20 g/denier%Tg C11.338330.006811.8450712.771.3694220.106123.555723.561.3804400.128843.027854.491.3841430.142064.5789Polyester fiber96*取向方向的拉伸强度显著提高*材料呈现各向异性的特性*热稳定性能得到相应提高972.5Liquidcrystalstate液晶态结构液晶态结构 98992.5.1液晶的化学结构与分类液晶的化学结构与分类n不论高分子还是小分子液晶，形成有序流体都不论高分子还是小分子液晶，形成有序流体都必须具备一定条件，从结构上讲，称其为必须具备一定条件，从结构上讲，称其为液晶液晶基元基元n液晶基元包括棒状液晶基元包括棒状(条状条状)、盘状或双亲性分子、盘状或双亲性分子n棒状棒状(或条状或条状)长径比大于长径比大于4n盘状盘状轴比小于轴比小于1/4n双亲性分子双亲性分子有特殊的相互作用力有特殊的相互作用力100MBBA2.5nm0.5nm5CB2nm101102103盘状液晶 DiscoticDiscotic Nematic DNDiscotic hexagonal ordered DhoDiscotic hexagonal disordered Dhd104按液晶基元所在位置分类按液晶基元所在位置分类主链型液晶侧链型液晶105按液晶形成条件分类按液晶形成条件分类热致液晶：通过加热而形成液晶态的物质热致液晶：通过加热而形成液晶态的物质-共聚共聚酯，酯，聚芳酯聚芳酯Xydar,Vector,Rodrum溶致液晶：在某一温度下，因加入溶剂而呈现液溶致液晶：在某一温度下，因加入溶剂而呈现液晶态的物质晶态的物质-核酸，蛋白质，芳族聚酰胺核酸，蛋白质，芳族聚酰胺PBT,PPTA(Kevlar)和聚芳杂环和聚芳杂环PBZT,PBO感应液晶：外场（力，电，磁，光等）作用下进感应液晶：外场（力，电，磁，光等）作用下进入液晶态的物质入液晶态的物质-PE under high pressure流致液晶：通过施加流动场而形成液晶态的物质流致液晶：通过施加流动场而形成液晶态的物质 -聚对苯二甲酰对氨基苯甲酰肼106结构结构结构结构液晶包括高分子液晶和小分子液晶。不论高分子还是小分子，形成有序流体都必须具备一定条件，从结构上讲，称其为液晶基元。液晶液晶基元基元棒状棒状(或条状或条状)长径比大于长径比大于4双亲性分子双亲性分子盘状盘状 轴比小于轴比小于1/4 分分分分类类类类按液晶核的排列分按液晶核的排列分按液晶基元按液晶基元所在位置分所在位置分按液晶的形成条件分按液晶的形成条件分棒棒状状盘盘状状向列相N：只有方向序无位置序近晶A相SA：有位置序和方向序近晶C相SC：有位置序和方向序且既有层面的法向方向又有晶核的共分方向柱相柱相向列相向列相(Discotic N)DN有有有有序序序序程程程程度度度度S SC CSSA ANN如果层内间隔相等如果层内间隔相等 Dho如果层内间隔不等如果层内间隔不等 Dhd主链液晶主链液晶主侧链液晶主侧链液晶侧链液晶侧链液晶热致液晶：液晶物质加热熔融形成的液晶。热致液晶：液晶物质加热熔融形成的液晶。溶致液晶：液晶物质溶于溶剂所得到的液晶。溶致液晶：液晶物质溶于溶剂所得到的液晶。107qHighrigidityqRod-likechainqStronginteractionKevlar/芳纶14Kevlar 49/芳纶14142.5.3 Properties and application of liquid crystal polymers 液晶高分液晶高分子的性能和应用子的性能和应用108Properties of some fibers 一些纤维的性能一些纤维的性能MaterialTensile strengthMPaYoungs modulusGPaElongation at break%Densityg/cm3Kevlar 49 fiber28001272.51.44UHMWPE fiber30001000.94Polyester fiber11001414.51.38Carbon fiber35302301.51.76Carbon whisker210001000SiC fiber30002201.42.55Glass fiber2500703.52.55Steel fiber18002042.07.83109c*各向同性液晶cT*各向同性液晶T液晶纺丝液晶纺丝110n液晶原位增强聚合液晶原位增强聚合n液晶显示液晶显示LCD-Liquidcrystaldisplayn液晶纺丝：液晶纺丝：在低牵伸倍数下获得高度取向、高性能纤维在低牵伸倍数下获得高度取向、高性能纤维液晶的应用液晶的应用111CrystallinestateAmorphousstateOrientationstateLiquidcrystallinestate三维有序，热力学稳定宏观无规线团，局部可能有序一维或二维有序，由外力诱导，热力学不稳定取向单元可以是链段，整链或晶粒一维或二维有序，热力学稳定取向单元是液晶基元1122.6 Structure of Multicomponent Polymers多组分聚合物的结构多组分聚合物的结构1132.6.1 Concept of multicomponent polymers 多组分聚合物的概念多组分聚合物的概念nDefinitionn含两种或两种以上高分子链的复合体系，其一种或几种主要性能明显优于单一组分nNomenclaturenMulti-component Polymers 多组分聚合物nMulti-phase Polymers 多相聚合物nPolymer Blend 高分子共混物nPolymer Alloy 高分子合金114Why multicomponent polymers？为什么要发展多组分聚合物为什么要发展多组分聚合物nRelatively few new polymers will be introduced commercially in the future because of unfavorable economics：nRequires new monomersnRequires change in current polymer synthesis processnRequires compliance with government premanufacturing regulationsnRequires years before profitabilitynPotential advantages of blending known polymers to produce new productsnLower cost of development and lower capital investmentnShortened time for testing and approval when work from known property data base of blended polymersnBlend preparation may be done in extrusion equipmentnPotential for use of recycled polymers115Some commercial polymer blends1162.6.2 Category of multicomponent polymers 多组分聚合物的品种多组分聚合物的品种nBlend 物理共混物n熔融共混、溶液共混nBlock copolymer 嵌段共聚物n活性阴离子聚合nGraft copolymer 接枝共聚物n自由基聚合nInterpenetrated Polymer Network 互贯聚合物网络n分别聚合117高分子材料均聚物均聚物聚合物基复合材料聚合物基复合材料共混物共混物共聚物共聚物交替共聚物接枝共聚物嵌段共聚物无规共聚物熔融共混物胶乳共混物溶液共混物互穿聚合物网络互穿聚合物网络多组分聚合物118n均相结构n两组分相容n单相连续结构n一相为连续相，形成基质（matrix）n一相为分散相，为颗粒状（domain）、棒状、蜂窝状等n两相连续结构n两相连续并互相贯穿，多见于IPNn两相互锁结构n两相互相交错，但均没有贯穿整个体系2.6.3 Structure of multicomponent polymers 多组分聚合物的结构多组分聚合物的结构ABSMultiphase119嵌段共聚物的形态嵌段共聚物的形态120直接观察共混直接观察共混物的透光性物的透光性TEM(Transmission electron microscopy)透射电镜和SEM(Scanning electron microscopy)扫描电镜观察分散相粒子大小测量共混物的测量共混物的 Tg-玻璃化转变温度玻璃化转变温度(Glass transition temperature）的变化）的变化透明：相容性好浑浊：相容性差相容性的表征相容性的表征 1212.6.4 Properties of multicomponent polymers 多组分聚合物的性能多组分聚合物的性能n均相结构：性能平均n多相结构：可能实现有利性能的结合 增强橡胶增强橡胶增韧塑料增韧塑料橡胶橡胶塑料塑料1222.6.5 Dispersion and coalescence in PE/PVC blends PE/PVC共混物的分散与粗化共混物的分散与粗化yxvxDispersionCoalescencePVC=19.5PE=16.6Immiscible123ExperimentalnMelt mixing was performed in a Haake rheological instrument.The components were loaded in the chamber and mixed with a rotor speed of 150rpm for 25min.Then,the rotor speed was decreased to 50rpm and mixed for another 25min.The mixed material was sampled during the process and the morphology was investigated with a phase contrast microscope 124PE/PVC(70/30)Dispersion35min25min15min5min45min50rpm 150rpm 125PE/PVC(70/30)Coalescence150rpm,25min 150rpm,25min+50rpm,25min 12650rpm 150rpm PE/PVC/CPE(70/30/7.5)Dispersion35min25min15min5min45min127PE/PVC/CPE(70/30/7.5)No Coalescence150rpm,25min 150rpm,25min+50rpm,25min 128PE/PVC/NBR(70/30/7.5)No Coalescence150rpm,25min 150rpm,25min+50rpm,25min 129Influence of compatibilizer on the tensile properties of PVC/LDPE(60/40)blend130POE增韧PS，加入AlCl3引发Friedel-Crafts烷基化反应，生成PS-g-POE接枝共聚物：R+C6H6+AlCl4-=C6H5 R+HCl+AlCl32.6.6 In-situ compatibilization of PS/POE with AlCl3131FTIR analysis132Morphology AlClAlCl3 3 content:(a)0,(b)0.2,(c)0.6,(d)1.0g content:(a)0,(b)0.2,(c)0.6,(d)1.0g133Impact strength 冲击强度冲击强度134Tensile strength 拉伸强度拉伸强度135Elongation at break 断裂伸长率断裂伸长率136本章重点：本章重点：1.结晶度的测定方法及原理2.晶胞的对称性及晶胞密度计算3.各种晶体结构模型4.球晶的各层次结构5.各种晶体的宏观形态6.无定形聚合物的几种主要模型7.取向态的形式8.液晶聚合物的分类及其聚集态结构137HomeworknAt least three of the ten problems in page 44-45138H7 2a=8.0 b=13.1 c=19.4=125monoclinic139Ve=a*b*c*cos(35)InaunitcellNumber of chains:4Number of repeating units per chain:7Total number of repeating units:28140聚乙烯在下列条件下缓慢结晶，各生成什么样的晶体？1.从极稀溶液中缓慢结晶；2.从熔体中结晶；3.极高压力下固体挤出；4.在溶液中强烈搅拌下结晶。1.单晶；2.球晶；3.伸直链晶体 4.纤维状晶或串晶141问题：问题：某一结晶性聚合物分别用注射和模塑两种方法成型，冷却水温都是20，比较制品的结晶形态和结晶度注射成型的冷却速度较快，且应力较大，所以往往生成小球晶或串晶，结晶度较低或不结晶。相反模塑成型的冷却速度较慢，球晶较大，结晶度较高。结晶形态与加工条件的关系结晶形态与加工条件的关系142问题：某注射成型制品截面内核芯区和皮层的结构示意图如下图，它们的广角x射线衍射图的主要差别是什么?(a)芯区：球晶 (b)皮层：串晶球晶的广角x射线衍射图是一系列锐利的衍射环；串晶皮层有取向，所以X射线衍射环会分裂成弧。143课堂演讲作业：课堂演讲作业：如何计算晶胞密度？WAXD在研究高分子结晶中的应用144nSinglecrystal:An isolated,microscopic-sized polymer crystal with no intercrystalline molecular connections.Formed only by very slow crystallization from dilute solution(at 0.1%).Typically it consists of a lozenge-shaped lamella about 100 thick often resulting from a collapsed pyramidal crystal.145
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