Structure_Property Behavior

Structure_Property Behavior - UNIVERSITY OF UNIVERSITY OF...

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Unformatted text preview: UNIVERSITY OF UNIVERSITY OF FLORIDA Polymeric Materials Polymeric Structure-Property Behavior Structure-Property A Review Dr. Anthony Brennan Plastics Processing 07/17/11 EMA 4666C Structure Property Behavior Review 1 UNIVERSITY OF UNIVERSITY OF FLORIDA Agenda • Overview of Plastics • General Classifications • Structure/Property Relationships • Plastics Processing • Plastics Industry • Experimenting with Plastics 07/17/11 EMA 4666C Structure Property Behavior Review 2 UNIVERSITY OF UNIVERSITY OF FLORIDA Polymer Structure -Property Polymer Behavior Behavior •chain chain thermodynamics thermodynamics •chain dimensions •chain environment •chain topography •mechanical behavior •circle 07/17/11 EMA 4666C Structure Property Behavior Review 3 UNIVERSITY OF UNIVERSITY OF FLORIDA Compare MD with TD for PE Film • Slowly draw each Dogbone • Observations? • Explain in a Physical Sense • Explain using Thermodynamics • Relate to Processing 07/17/11 EMA 4666C Structure Property Behavior Review 4 UNIVERSITY OF UNIVERSITY OF Stress (A.U.) FLORIDA A 07/17/11 Stress - Strain Response •A: Modulus-chain A: entanglements, bond rotation rotation •B: Yielding-chain B: D disentanglement, volume B C expansion expansion •C: Strain HardeningC: chain viscous motion, chain alignment chain •D: Failure-chain bond D: Strain breakage, reduction in EMA 4666C Structure Property Behavior Review 5 molar mass molar UNIVERSITY OF UNIVERSITY OF FLORIDA Observations •Difference in total Difference elongation elongation •Difference in applied Difference stress stress •Necking •Exam changes Exam in stress strain stress response response •Whitening •Retraction upon Retraction failure failure 07/17/11 EMA 4666C Structure Property Behavior Review 6 UNIVERSITY OF UNIVERSITY OF Stress - Strain Response A B Stress (A.U.) FLORIDA C D •A: High frequency (τ << t), Low temperature (T<<Tg,Tm), high crystallinity high •B: Decreasing frequency, (τ ~t) (T~Tg, T<Tm) ~t) •C: Decreasing frequency C: (τ >t), decreasing crystallinity, (T>Tg, T<Tm) crystallinity, •D: Low frequency (τ >>t), high temperature (T>>Tg, T~Tm), low crystallinity T~Tm), Strain 07/17/11 EMA 4666C Structure Property Behavior Review 7 UNIVERSITY OF UNIVERSITY OF FLORIDA Chain Energy (Thermodynamics) HEAT H - bonding COOL ∆G = ∆Η 07/17/11 − Τ∆ S EMA 4666C Structure Property Behavior Review 8 UNIVERSITY OF UNIVERSITY OF FLORIDA Balance of Three Energies •Intramolecular – PE vs Nylon 6 – Nylon 6 vs Kevlar – Kevlar vs Nomex •Intermolecular – Nylon 6 : 10 to 20 Nylon kcal/mol (Tm: 220°C) kcal/mol – Kevlar: >20 kcal/mol •Secondary Bonding – H-Bonds, Dipole, H-Bonds, Ionic, van der Waals Ionic, – Nylon vs PE •Thermal – kT per repeat unit 07/17/11 •Bond rotation – 2 to 11 kcal/mol •Low energy – ~0.6 kcal/mol EMA 4666C Structure Property Behavior Review 9 UNIVERSITY OF UNIVERSITY OF FLORIDA Polymer Structure -Property Behavior Chain Dimensions • conformation – spatial arrangement – changes with rotation around bonds • configuration – bonding arrangement – changes only through bond breakage • aspect ratio (L/D) for PE (100kg/mol) – 60,000 07/17/11 EMA 4666C Structure Property Behavior Review 10 UNIVERSITY OF UNIVERSITY OF FLORIDA Polymer Structure -Property Behavior Chain Dimensions •Dependent upon •Controls – composition – configuration – viscosity – Tg – molar mass – temperature – modulus – elongation – pressure – solubility – processability – stability 07/17/11 EMA 4666C Structure Property Behavior Review 11 Polymer Structure -Property Behavior Thermodynamics •Glass transition (Tg) •Melting transition Melting – solid to liquid (Tm) (Tm) UNIVERSITY OF UNIVERSITY OF FLORIDA – second order second transition transition – modulus decreases modulus by 2 to 3 orders of magnitude magnitude – elongation increases – volume expansion volume rate increases (CTE) rate – ~2/3 Tm 07/17/11 – solid to liquid – first order first transition transition – modulus modulus decreases by 2 to 3 orders of magnitude magnitude – volume expansion volume discontinuous discontinuous EMA 4666C Structure Property Behavior Review 12 UNIVERSITY OF UNIVERSITY OF FLORIDA Polymer Structure -Property Behavior Chain Dimensions - Measurement •Absolute Methods – Mn •Relative Methods – GPC • Membrane Osmometry • Freezing Pt depression • Boiling Pt. elevation – Mw • Solution light scattering – Mz – Viscosity – Vapor phase Vapor osmometry osmometry – Fractionation – End group End titration titration • ultracentrifugation 07/17/11 EMA 4666C Structure Property Behavior Review 13 UNIVERSITY OF UNIVERSITY OF FLORIDA Gel Permeation Chromatography Σc ΣNM Mn = = Σc/M ΣN 2 Σ cM ΣNM Mw = = Σ c ΣNM 1 a injector ΣNM ΣcM = MV = Σc ΣNM 2 3 Σ cM ΣNM MZ = = 2 Σ cM ΣNM 07/17/11 (1+ i) 1 a EMA 4666C Structure Property Behavior Review detector 14 UNIVERSITY OF UNIVERSITY OF FLORIDA Viscosity •Viscosity Viscosity (solution) (solution) – hydrodynamic hydrodynamic volume volume – relative – inherent – intrinsic (Mv) η − η0 [η ] = limc→0 cη 0 η0 = KM a V – Mark-Houwink M N < MV < MW < M Z 07/17/11 EMA 4666C Structure Property Behavior Review 15 UNIVERSITY OF UNIVERSITY OF FLORIDA Polydispersity Polydispersity – Mechanical Mechanical Properties Properties – Processing – Stability 07/17/11 Mw PDI = Mn σ = Mn Mw −1 Mn EMA 4666C Structure Property Behavior Review 16 UNIVERSITY OF UNIVERSITY OF FLORIDA Polymer Structure -Property Behavior Chain Dimensions •Viscosity Viscosity (solution) (solution) – hydrodynamic hydrodynamic volume volume – relative •Gel Permeation Gel Chromatography (GPC) (GPC) – hydrodynamic volume – size exclusion – inherent – intrinsic (Mv) – universal calibration – Mn (number average) – Mark-Houwink – Mw (weight average) – Mz (z-average) •Viscosity (melt) – similar 07/17/11 EMA 4666C Structure Property Behavior Review 17 UNIVERSITY OF UNIVERSITY OF Williams-Landel-Ferry FLORIDA • Temperature – size increases with increasing temperature – viscosity decreases with increasing viscosity temperature temperature – governed by WLF equation η (T1, t ) 07/17/11 − 17.4 (T − Tg ) ∝ η (T2 , t ) 51.6 + (T − Tg ) EMA 4666C Structure Property Behavior Review 18 UNIVERSITY OF UNIVERSITY OF FLORIDA Polymer Structure -Property Behavior Chain Environment -Plasticization • Low Molar Mass Molecules – decreases Tg – decreases viscosity – governed by Flory-Huggins Relationship – “like dissolves like” – requires a negative ∆ H requires – reduces melting point – eg. PVC • vinyl siding versus raincoats 07/17/11 EMA 4666C Structure Property Behavior Review 19 UNIVERSITY OF UNIVERSITY OF FLORIDA Polymer Structure -Property Behavior Chain Topography •Bulkier side Bulkier groups raise Tg groups •Longer flexible Longer units lower Tg units 07/17/11 EMA 4666C Structure Property Behavior Review 20 UNIVERSITY OF UNIVERSITY OF THERMOMECHANICAL PROPERTIES Anhydride Epoxy FLORIDA 10 9 Postcured Time (hrs) o @ 125 C 8 8 8 16 -1.0 16 24 24 -2.0 7 -100 Postcured Time (hrs) @ 125oC Log Tan δ Log E ' (Pa) 0.0 -50 0 50 100 150 Temperature (oC) 200 250 -100 -50 0 50 100 150 200 250 Temperature (oC) Frequency = 1 Hz, heating rate = 0.75oC/min., N2 flow rate = 200 ml/min. 07/17/11 EMA 4666C Structure Property Behavior Review 21 UNIVERSITY OF UNIVERSITY OF FLORIDA 0 -80 Viscoelasticity of PUR -40 0 40 80 120 160 Temperature (°C) DMS of a DMS Polyurethane copolymer copolymer 07/17/11 EMA 4666C Structure Property Behavior Review 22 UNIVERSITY OF UNIVERSITY OF FLORIDA Viscoelastic Functions Compliance – Reciprocal of Modulus 1 − e J (t ) = J U + ( J R − J U ) −t e τ J (t ) = A −t τ Time dependence demonstrated. 07/17/11 EMA 4666C Structure Property Behavior Review 23 UNIVERSITY OF UNIVERSITY OF FLORIDA Sinusoidal Test - DMTA τ ( t ) = τ o cos ω t Applied Stress Strain Response γ ( t ) = γ o cos ω t Ideally Viscous Liquid (Newtonian) 07/17/11 π γ ( t ) = γ o cos (ω t − ) 2 EMA 4666C Structure Property Behavior Review 24 UNIVERSITY OF UNIVERSITY OF FLORIDA Viscoelastic Behavior Input τ ( t ) = τ o cos ω t γ ( t ) = γ o cos (ω t − δ ) Response 07/17/11 EMA 4666C Structure Property Behavior Review 25 UNIVERSITY OF UNIVERSITY OF FLORIDA Viscoelastic Behavior τ (t) τo e G= = γ (t) γo τo = (cos δ + i sin δ ) γo = G ' + iG" * 07/17/11 iδ EMA 4666C Structure Property Behavior Review 26 UNIVERSITY OF UNIVERSITY OF FLORIDA Tan δ Derived from DMTA Tan Derived G * = G ' + iG" G" tan δ = G' 07/17/11 EMA 4666C Structure Property Behavior Review 27 UNIVERSITY OF UNIVERSITY OF FLORIDA 07/17/11 Thermal Transitions EMA 4666C Structure Property Behavior Review 28 UNIVERSITY OF UNIVERSITY OF FLORIDA Condensation Polymers •Nylon 6,6 – A-A Monomer: adipic acid – B-B Monomer: 1,6 hexane diamine – A Monomer: End Monomer: group group – B Monomer: 07/17/11 •Properties – Tg ~ 55°C – Tm ~ 250 - 265°C – Process: 500 to Process: 600°F 600°F EMA 4666C Structure Property Behavior Review 29 UNIVERSITY OF UNIVERSITY OF FLORIDA Condensation Polymers • Poly(bis phenol A Poly(bis carbonate) carbonate) – A-A Monomer: Bis phenol A-A A – B-B Monomer: phosgene – A Monomer: End group O CH3 HO C OH + Cl CH3 O CH 3 O C O C CH 3 n • Properties – Tg = 150°C – Processing ~ 520 to 560°F 07/17/11 C EMA 4666C Structure Property Behavior Review 30 Cl UNIVERSITY OF UNIVERSITY OF FLORIDA Condensation Polymers • Kevlar – A-A Monomer: terephthalic acid – B-B Monomer:p-phenylene diamine HOOC C OOH – A Monomer: End group • Nomex C OOH – A-A Monomer: isophthalic acid O H N 07/17/11 HOOC O C C N EMA 4666C Structure Property Behavior Review n H 31 UNIVERSITY OF UNIVERSITY OF FLORIDA Chain Growth Polymer • Nylon 6 – A-A Monomer: caprolactam – A Monomer: – B Monomer: • Properties – Tm ~ 220°C – Process ~440 to 525°F 07/17/11 EMA 4666C Structure Property Behavior Review 32 UNIVERSITY OF UNIVERSITY OF FLORIDA Polymer Structure -Property Behavior Crystallites •Spherulite •Mozaic – lamellae – folded chain – liquid crystalline – smectic – tie chain/molecule – quiescent conditions – nematic – cholesteric – flexible chain – high shear, high solution solution – rigid rod chain or rigid side chain side •Row nucleated – lamellae – shear field, i.e., shear extruded 07/17/11 extruded melt 4666C Structure Property Behavior Review EMA 33 UNIVERSITY OF UNIVERSITY OF FLORIDA Crystalline Morphology Of Polymers Fringed Micelle Staudinger - PET, Nylon 10 nm 07/17/11 EMA 4666C Structure Property Behavior Review 34 UNIVERSITY OF UNIVERSITY OF FLORIDA Crystalline Morphology Of Polymers Folded Chain Model Keller 1957 P.E. 10-20 nm Single Crystal Contour length of PE chains were 200 nm, thus they must have been folded 07/17/11 EMA 4666C Structure Property Behavior Review 35 UNIVERSITY OF UNIVERSITY OF FLORIDA EM of PE - Keller EM PE single crystal PE 07/17/11 EMA 4666C Structure Property Behavior Review 36 UNIVERSITY OF UNIVERSITY OF FLORIDA 07/17/11 Switchboard Morphology EMA 4666C Structure Property Behavior Review 37 UNIVERSITY OF UNIVERSITY OF FLORIDA 07/17/11 Adjacent Reentry Morphology EMA 4666C Structure Property Behavior Review 38 UNIVERSITY OF UNIVERSITY OF FLORIDA Non-adjacent Reentry Morphology 07/17/11 EMA 4666C Structure Property Behavior Review 39 UNIVERSITY OF UNIVERSITY OF FLORIDA 07/17/11 PE Lattice Structure EMA 4666C Structure Property Behavior Review 40 UNIVERSITY OF UNIVERSITY OF FLORIDA Rate of growth Edge view Nucleation of Lamellae Top view 07/17/11 EMA 4666C Structure Property Behavior Review 41 UNIVERSITY OF UNIVERSITY OF FLORIDA 07/17/11 Rate of growth EMA 4666C Structure Property Behavior Review 42 UNIVERSITY OF UNIVERSITY OF FLORIDA Summary • Thermodynamics govern the Thermodynamics properties of polymers properties • Composition and topography Composition determine structure and thus properties such as Tg, Tm, Modulus, Viscosity, etc. Viscosity, • Properties vary logarithmically with Properties time and linearly with temperature time 07/17/11 EMA 4666C Structure Property Behavior Review 43 UNIVERSITY OF UNIVERSITY OF FLORIDA References • Fundamental Principles of Polymeric Fundamental Materials, 2nd Edition, Stephen L. Rosen, Wiley Interscience (1993) ISBN 0-471-57525-9 Wiley • Introduction to Physical Polymer Science, Introduction 2nd Edition, Lesley H. Sperling, Wiley Interscience (1992) ISBN 0-471-53035-2 Interscience • Polymer Science and Technology, Joel R. Polymer Fried, Prentice Hall PTR (1995) ISBN Fried, 07/17/11 EMA 4666C Structure Property Behavior Review 44 ...
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This note was uploaded on 07/17/2011 for the course EMA 4666c taught by Professor Brennan during the Spring '08 term at University of Florida.

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