高物高分子物理課件chapter

1、Chapt.Molecular andChapt.Molecular andTransitions of S 6.1Molecularmotionsof 特點, 基本類型e Glass transitionof意義, 表征, 理論Viscous flowof 特點, 表征, 影響16.1高聚物的分子熱運動1. 主要特運動單元的多重6.1高聚物的分子熱運動1. 主要特運動單元的多重:relaxation與運動單元有關(guān)與溫度有關(guān)xx etx0 0eE/a指數(shù)形式bWLF方程(3) 與觀察時的時間標(biāo)尺t2ViscoelasticityofElasticityandHookeslawViscoelas

2、ticityofElasticityandHookeslawdescribesthebehaviorofa linearelasticsolidNewtonstofa linearviscousSpringasam Modulus:Dashpotasa :Viscosity粘度Hookeslaw: =stress應(yīng)力Newtonslaw: = strain應(yīng)變3Elasticity+ Viscosity= Viscoelasticityd2 1 2Elasticity+ Viscosity= Viscoelasticityd2 1 2 1 d 1 d MaxwellForstress rela

3、xation, d/dt=tE tmAttime t =0, =0Relaxationtime: = 4t expt 粘彈性-力學(xué)松弛行粘彈性-力學(xué)松弛行52. 力學(xué)狀態(tài)與熱轉(zhuǎn)T次級松形變不可回復(fù)高彈性力學(xué)性質(zhì)普彈性運動單元2. 力學(xué)狀態(tài)與熱轉(zhuǎn)T次級松形變不可回復(fù)高彈性力學(xué)性質(zhì)普彈性運動單元鏈段鏈段鏈段分子實驗不可測范松弛時間實驗可測實驗可測6Semi-crystallineor crystalline TmTfCrystalline6.216.21237GlassTransitionas a RelaxationsThermalhistoryGlassTransitionas a Relax

4、ationsThermalhistorydependenceof 1:fast2:slowTemperature dependence of the specific volume of PVA, measured during heating.Dilatometric (膨脹計法results after a quench to 20C, followed by 0.02 100h of storage. (Kovacs, A. J. THochpolym. Forsch. 1966,3, 8V4. 現(xiàn)象和實驗表(1(2(3玻璃高彈4. 現(xiàn)象和實驗表(1(2(3玻璃高彈粘流 0(495Fre

5、eVolume Freevolume: aconcept5FreeVolume Freevolume: aconceptusefulindiscussing chas viscosityandinThe segmentalmotionof polymer chain requires more volumeOccupied volume: filled circles; free Holetheoryofliquid: the liquidconsistsofmatterand holes. The largervolume ofliquid when comparedto the cryst

6、alis representedby a number of holes of afixedvolume. The holesrepresent zed freevolume, whichcanredistributedby movementorcollapse inone placeand creationinFreeVolume dV VT dT The coefficient of thermal expan (CTE,熱膨脹系數(shù)isconstant for the occupiedvolumeforbothtemperaturebelowand above The volume-tem

7、perature fora typical amorphous polymer Vf: free volume at T Tg (Vf)T: free volume at T Tg Vt: total volume at T Tgthe temperature below T gthefreevolumeisconstant; and the volumeFreeVolume dV VT dT The coefficient of thermal expan (CTE,熱膨脹系數(shù)isconstant for the occupiedvolumeforbothtemperaturebelowan

8、d above The volume-temperature fora typical amorphous polymer Vf: free volume at T Tg (Vf)T: free volume at T Tg Vt: total volume at T Tgthe temperature below T gthefreevolumeisconstant; and the volumewillincreasewithtemperature when temperature exceed TgV0:occupied volume(determined dV dV T T vande

9、reraction +VVTV dT dT gf0grggdV/dT):CTEoftheglass- andrubber-geT dV dV dV dV V VT TT dT dT dT dT g fffT TTTdV dV VfTTf dT dT ggfVg f T Tg gfT fg(T Tg1 dV 1 dV dT dT fVVgggFreeVolume Theory AexpBV /VRelationof the molecularmobilityto free volume: Doolittle equationln V (T)FreeVolume Theory AexpBV /VR

10、elationof the molecularmobilityto free volume: Doolittle equationln V (T)(T(TgV B 0Vf (TVf (Tg)(TgfVf (TVf (TNormalizedfreeTV (T)V (TV (T0f0fg f TTg fT (T B 1 1 T fg /f TTg 2.303 fg(TTglog(Tlog(TWLF (Tg51.6(TTg (Tgfg 0.025equalto 1fg4.8104/ffAppendix:Doolittle equation & Einstein Doolittle AexpBV /A

11、ppendix:Doolittle equation & Einstein Doolittle AexpBV /Vandthevolume fraction1InV V0 /Vfsf0Einstein Forthe solutionof impenetrablespheresof radius R, EinsteinderivedEffectiveviscosityof 0 12.5sp.69of ChainMorerigidchainpresenthigher Tvs.mg/Tm 1/Forsymmetricalbackbone, MolecularweightTg /Tm 2/ChainM

12、orerigidchainpresenthigher Tvs.mg/Tm 1/Forsymmetricalbackbone, MolecularweightTg /Tm 2/ForasymmetricalT () FoxggMT nmHeatingratemTgvs. eE/ 0T 高度柔性和剛性鏈tgbt1/v 升溫速度t停留時間Tg f中度剛性鏈強迫高彈形變Tg1Tt tT1s1f1tstf g1tf g2EffectsoffilmEffectsoffilmthickness onTsui,OKC,Macromolecules, 34,5535Glass transition of pol

13、ymer Somepolymerblends exhibitpartial miscibility. Theyhave amutual, solubilityindicatedby Glass transition of polymer Somepolymerblends exhibitpartial miscibility. Theyhave amutual, solubilityindicatedby a hetwopanyingaphaseitionof the blend. monisthe type ofindicatedby the presenceof only single l

14、edPartialww1 Fox-FloryTgof lend Plasticization of PVC: Tg as function of di(ethylhexyl)-DSC curves of 50mass-% blends of PS and poly(-methyl styrene) at aandPS as a function of content.(Bair, H. E. Polym. Eng. Sci. 1970, 10, 247.)latecontent. (Wolf, heatingrate of 10 K/min. (Lau, S.F.; etc. Macromol

15、ecules 1982, 15, 1278.)Kunststoffe 1951, 41, EffectsofTg onEffectsofTg onMorphologyof PolymerTanakaH,J PhysCondens12,R207ChengSZD,KellerA,Ann RevMaterSci,28,5336.3Viscous Flow ofTherheological6.3Viscous Flow ofTherheological properties流變性質(zhì)polymersisextremelyimportantRheology: The study of the deform

16、ation and flow of matter.Characteristicofpolymerviscous 1. 鏈段的蠕動實現(xiàn)整個分子的遷移2. Characteristicofpolymerviscous 1. 鏈段的蠕動實現(xiàn)整個分子的遷移2. 不符合流體的規(guī) Characteristicofpolymerviscous 時伴有高彈Characteristicofpolymerviscous 時伴有高彈形Considera steadysimpleshearShearShearDie-(出口長大Extrudate swell observed for a melt of PS for

17、various shear ratesand temperatures. (Burke, J. J.; etc.Characterization of Materials in Research, Syracuse Univ. Press, Characterization ofviscous三種最基本的(形變)-shearviscosityCharacterization ofviscous三種最基本的(形變)-shearviscosity(形變)-tensileviscositya.剪切b.拉伸velocityc.壓縮bpresibleMelt viscosities of dhMelt

18、viscosities of dhs1-2-a dha s0 0 sint /2 sin t0Measurementofsheareter -anMrHRhrtanMeasurementofsheareter -anMrHRhrtan dv r h b a3Theflowcurveofpolymer td0零切粘pTheflowcurveofpolymer td0零切粘pplog00dependentof Criticalmolecularentanglement纏結(jié)limit0dependentof Criticalmolecularentanglement纏結(jié)limitM Mc M Mc RouseMMWWMM0Tubeion)0EffectsofTemp.,ShearRateShearStress on分子量與分子分子量與分子量分溫度-Vogel-Fuchler 方 Aexp/T T0 剪切應(yīng)力與剪切速鏈結(jié)構(gòu)-支分子結(jié)構(gòu)的柔順分子3. 外力作Normal stressdifferenceandElasticeffectson viscous flow of polymersAF