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旋转流变仪及其 测量技术简介

金建青年学术 沙龙第十期. 旋转流变仪及其 测量技术简介. 工程塑料实验室 张宝 庆 zhangbq@iccas.ac.cn 2014-9-3. 主要内容. 一、流变学基础 知识 简介 二、旋转流变仪简介 三、基于旋转流变仪平台的测量技术. Linear Viscoelasticity. V iscoelastic relaxation modulus of flexible linear polymers. Polym J . 2009, 41( 11 ), 929. strain g. unit area.

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旋转流变仪及其 测量技术简介

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  1. 金建青年学术沙龙第十期 旋转流变仪及其测量技术简介 工程塑料实验室 张宝庆 zhangbq@iccas.ac.cn 2014-9-3

  2. 主要内容 一、流变学基础知识简介 二、旋转流变仪简介 三、基于旋转流变仪平台的测量技术

  3. Linear Viscoelasticity Viscoelastic relaxation modulus of flexible linear polymers. Polym J. 2009, 41(11), 929.

  4. strain g unit area  = G(t)g unit height Stress Relaxation (Transient Test)

  5. Superposability of Stress g 2 1 t t1 t2 s 1 2 1+2 t t1 t2 Just for g1 1(t) = G(t-t1)g1 Just for g2 2(t) = G(t-t2)g2 Forg1 + g2 1+2(t) = 1(t) + 2(t) = G(t-t1)g1 + G(t-t2)g2

  6. Boltzmann Principle  for strain g(t) of arbitrary history dgi t dt'  di t ti t For infinitesimal strain dgi at time

  7. Boltzmann Superposition Principle The principle of linear superposition of stresses and/or deformations： • The response to any event is linear； • All consequent events lead to independent responses. The material reacts to the next action as if no former action took place! Rheology: Concepts, methods and applications. Page 61.

  8. Linear Viscoelasticity (Oscillatory Shear) Input Output η*: complex viscosity

  9. Frequency Defined Test Input: strain (g), frequency (w), and gap (H). Measure: torque (M) and phase angle (d).

  10. Frequency Sweep The amplitude of the perturbation can be freely chosen for each frequency, and dynamic modulus measurement is so far the most common method of linear viscoelastic characterization currently.

  11. Stress Relaxation vs.Frequency Spectrum G(t) vs. t G'(ω) vs. ω A is monodisperse with M<Mc; B is monodisperse with M>>Mc and C is polydisperse LVE response is very sensitive to the molecular structure of the polymers

  12. Dynamic Compliance J*(ω) Dynamic Modulus G*(ω) Algebraic Equations Fourier Transforms Fourier Transforms Creep Compliance J(t) Relaxation Modulus G(t) Integral Equations Laplace Transforms Laplace Transforms 线性粘弹性函数之间的关系 Retardation Time Distribution L(τ) Relaxation Time Distribution H(τ) Integral Transforms 12 Polymeric liquids and networks – Dynamic and rheology. Page 122.

  13. Time-Temperature Superposition (TTS) WLF (Williams-Landel-Ferry) equation 13

  14. Time-Temperature Superposition (TTS) Thermorheologicallysimple Master curve of the linear viscoelastic moduli 14 J Rheol. 2011, 55(5), 987.

  15. Creep – Creep Recovery Recoverable Non-Recoverable Principle of a creep-recovery experiment J Rheol. 2014, 58(3), 565.

  16. Dynamic Compliance J*(ω) Dynamic Modulus G*(ω) Algebraic Equations Fourier Transforms Fourier Transforms Creep Compliance J(t) Relaxation Modulus G(t) Integral Equations Laplace Transforms Laplace Transforms 线性粘弹性函数之间的关系 Retardation Time Distribution L(τ) Relaxation Time Distribution H(τ) Integral Transforms 16 Polymeric liquids and networks – Dynamic and rheology. Page 122.

  17. 聚合物流变学的“链接”作用 ProgPolym Sci. 2001, 26(6), 895. 17

  18. 主要内容 一、流变学基础知识简介 二、旋转流变仪简介 三、基于旋转流变仪平台的测量技术

  19. AR-Series Hybrid-Series Aton Paar Malvern ARES ARES-G2 旋转流变仪的种类 应变控制型 （SMT） 应力控制型 （CMT） 19 Separate Motor and Transducer

  20. 旋转流变仪的种类 FRT Motor Inertia & friction Involved in Torque Measurement Motor/Transducer Torque Measurement is Unaffected by Motor Inertia & Friction Primary Moving Elements Motor 应力控制型 （CMT） 应变控制型 （SMT） 20

  21. Strain vs. Stress controlled Stress Controlled OKfor oscillatory measurements Good for fixed stress measurements Good for creep measurements Drag cup motors often cannot do low stresses well EC motors often have more inertial effects Often assumes certain type of material response Strain Controlled Good for oscillatory measurements Good for fixed shear rate/strain measurements (Stress relaxation) Motors are really good - good for weak materials Very sensitive torque transducers 两种流变仪差别越来越小！

  22. 决定流变仪性能的重要参数（时间分辨率） • Torque range • （扭矩范围） • Angular Resolution • （角位移分辨率） • Angular Velocity Range • （角位移速率范围） • Frequency Range • （可测频率范围） • Normal Force • （法向力范围） • Motor type • （驱动马达类型）

  23. 流变仪如何得到流变数据 一个周期内得到时间间隔为Δt的N个点 From the time into the frequency domain Discrete Fourier transformation (DFT)

  24. 信噪比(S/N)与取样速率(n points/cycle)关系

  25. Testing Geometries Concentric Cylinder Single/double-gap Parallel Plates Cone Plate ○ 用量少(~0.5 - 3 mL) ○ 非均匀应变 ○ 制样简单 ○ 可用于变温测试 ○ Gap可变，用于界面滑移的表征 ○ Gap可变，shear rate随之改变 ○用量少(～ 1 mL) ○均匀应变 （真实粘度) ○第一法向应力差测试 ○不适用于较大粒子的分散体系 ○对间距设置更敏感 ○不适用于变温测试 ○高粘度流体制样有困难 ○ 适用于低粘度样品 ○均匀应变场 ○样品用量大(~9 mL) ○清洁困难 ○末端效应校正

  26. Testing Geometries M (扭矩) — τ (应力)，ω(角速度)—(剪切速率）

  27. Extensional Viscosity Fixture (EVF)

  28. Extensional Viscosity Fixture (EVF) 对于ARES-G2 拉伸速率 ≤ 10 s-1, 拉伸应变

  29. 主要内容 一、流变学基础知识 二、旋转流变仪简介 三、基于旋转流变仪平台的测量技术

  30. Rheological Measurements • Flow tests • Constant shear rate • Continuous stress/rate ramp and down • Steady state shear rate sweep • Flow temperature ramp • Flow reversal • Oscillation tests • Frequency sweep • Time sweep • Strain/stress sweep (LVE) • Temperature ramp • Temperature/Frequency sweep (TTS) • Fast Sampling • Multiwave • Transient tests • Stress relaxation • Creep & creep recovery • others • Elongational test • LAOS • Strain-Rate Frequency Superposition (SRFS)

  31. Slow Relaxation Behavior of Linear Chains Polybutadiene, 40C relaxation time t ~ M3.4±0.2 Delay of orientation/stress relaxation due to entanglement of uncrossable chains

  32. Slow Relaxation of Star-branched Chains PBD: Linear Mw=160K 6-arm star Ma=77K Relaxation time t ~ exp(0.6Marm/Me) Much stronger delay for star chain cf.  ~ M3.4±0.2 for linear chain

  33. 利用蠕变测试扩展SAOS测试频率 Example for the extension of the frequency range using the retardation spectrum obtained from creep-recovery tests (recover time up to 104 s). J Rheol. 2014, 58(3), 565.

  34. 利用应力松弛测试扩展SAOS测试频率 UHMWPE DFreq SR ARES-G2 Fourier Transforms Relaxation Modulus G(t) Dynamic Modulus G*(ω)

  35. Oscillation Time Sweep Re-entanglement kinetics of freeze-dried polymers (a) Buildup of modulus in polystyrene samples with time. (b) Equilibrium entanglement time of samples freeze-dried from solutions with different original concentrations. Macromolecules. 2012, 45 (16), 6648 .

  36. Oscillation Time Sweep Effect of thermally reduced graphite oxide (TrGO) on the polymerization kinetics of poly(butylene terephthalate) Polymer. 2013, 54 (6), 1603.

  37. MultiwaveOscillation • The total strain amplitude should not exceed the linear viscoelastic regime • The test time is the same as the dynamic single point experiment under the fundamental frequency

  38. MultiwaveOscillation Evolution of the loss tangent during a curing reaction. The gel point is the point, when tan δ becomes independent of frequency.

  39. Oscillation Temperature Ramp Cross-linking kinetics of XLPE

  40. Oscillation Temperature Ramp Phase separation temperature of polymer blends PS/PVME with big difference in Tg PB/PI with big discrepancy in viscoelasticity Miscible Metastable Phase-separated Dynamic temperature s ramp for a 50:50 PS 38K/PVME-23K blend J PhysChem B.2004, 108 (35), 13220.

  41. Steady Shear Stress/Rate Sweep Physics Today. 2009, 62(10), 27.

  42. Shear Reversal Results of flow reversal studies of a 4.80 wt% PP/clay hybrid nanocomposite. Macromolecules. 2001, 34 (6), 1864.

  43. ElongationalTest-1 Polylactide with long-chain branched structure Strain-hardening coefficient: IndEngChem Res. 2014, 53(3), 1150.

  44. ElongationalTest-2 (a) Chewing and (b) bubble gum behavior during start-up of uniaxial extension J Rheol. 2014, 58(4), 821.

  45. 聚合物流变学的“链接”作用 ProgPolym Sci. 2001, 26(6), 895. 45

  46. Further Readings The Rheology Handbook-For Users of Oscillatory Rheometers ( 3rd ed.) Thomas G. Mezger 2013 Structure and Rheology of Molten Polymers: From Structure To Flow Behavior and Back Again John M. Dealy, Ronald G. Larson. 2006

  47. Further Readings Melt Rheology and Its Applications in the Plastics Industry John M. Dealy , Jian Wang 2013 Colloidal Suspension Rheology Norman J. Wagner, Jan Mewis. 2012

  48. Further Readings Viscoelastic Properties of Polymers (3rd Revised) John D. Ferry 1980 Rheology: Principles, Measurements, and Applications Ch. W. Macosko 1994

  49. Rheology Related Journals • Journal of Rheology • RheologicaActa • Journal of Non-Newtonian Fluid Mechanics • Applied Rheology • Korea-Australia Rheology Journal • Nihon ReorogiGakkaishi (Journal of Society of Rheology Japan) • Macromolecules • Langmuir • Soft Matter • Physical Review Letters • Physical Review E • Journal of Chemical Physics

  50. 仪器公司网站

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