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Pressure Quench of flow-induced crystallization

Putting values to a model for Flow Induced Crystallization (DPI #714,VALFIC). Pressure Quench of flow-induced crystallization. Zhe Ma, Luigi Balzano, G errit W M Peters Materials Technology Department of Mechanical Engineering Eindhoven University of Technology. Z. Ma, G.W.M. Peters

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Pressure Quench of flow-induced crystallization

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  1. Putting values to a model for Flow Induced Crystallization (DPI #714,VALFIC) Pressure Quench of flow-induced crystallization Zhe Ma, Luigi Balzano, Gerrit WM Peters Materials Technology Department of Mechanical Engineering Eindhoven University of Technology • Z. Ma, G.W.M. Peters • Materials Technology • Department of Mechanical Engineering • Eindhoven University of Technology

  2. motivation flow structures properties

  3. motivation structure flow strength depending on the molecular mobility strong mild quiescent (no flow) oriented nuclei point-like nuclei, f(T) more point-like nuclei nuclei [1] Swartjes F.H.M (2001) PhD thesis, Eindhoven University of Technology, NL [2] Hsiao B.S et al. (2005) Physical Review Letter, 94, 117802

  4. objective How to observe nuclei: Small Angle X-ray Scattering (SAXS) Wide Angle X-ray Diffraction (WAXD) …… flow SAXS electron density difference Limitation: precursors without electron density difference (or very little concentration) WAXD  crystalline structure Limitation: non-crystalline precursors

  5. objective observable point-like nuclei No crystallization after flow row nuclei -- No oriented nuclei formation during flow shish nuclei – Yes

  6. objective observable point-like nuclei crystallization after flow (kinetics) No row nuclei -- No oriented nuclei shish nuclei – Yes

  7. objective develop a method which is (more) reliable, simple, also works with flow.

  8. suspension-based model[1] ? space fillingf nucleation density N(T) measure G*(T) Avrami Equation linear viscoelastic three dimensional generalized self-consistent method[2] Relative dynamic modulus,f*G=G*/G*0 A*, B* and C*determined by ratio of the complex moduli of the continuous phase and dispersed phase, Poisson ratio of both phases: all known, A*, B* and C* then depend on space filling only. [1] R.J.A. Steenbakkers et al. Rheol Acta (2008) 47:643 [2] R.M. Christensen et al. J.Mech.Phys.Solids (1979) 27:315

  9. suspension-based model iPP and U-Phthalocyanine(145oC) method suitable for combined effect of NA and flow Z Ma et al. Rheol Acta (2011) DOI 10.1007/s00397-010-0506-1

  10. objective observable point-like nuclei No crystallization after flow (orientation and kinetics) row nuclei -- No oriented nuclei shish nuclei – Yes

  11. objective crystallization: 1. morphology (isotropic or oriented) 2. kinetics (compared with quiescent case) Undercooling is expected to start crystallization decrease Texp by fast cooling --- Temperature quench difficult for large devices increase Tequilibrium by pressure --- Pressure quench!

  12. Pressure-quench Set-up Multi-Pass Rheometer (MPR) Protocol Erase history at 190oC and cool to 134oC A apparent wall shear rate: 60 1/s shear time: 0.8s 300bar reference 50bar

  13. c b 50bar a c a b Pressure-quench Pressure Quench t=0s t=17s flow highly oriented crystals twisted lamellae row nuclei

  14. Pressure-quench Set-up Multi-Pass Rheometer (MPR) Protocol Erase history at 190oC and cool to 134oC A apparent wall shear rate: 60 1/s shear time: 0.8s 300bar reference 50bar annealing after flow, ta=22min

  15. no annealing 0s 8.5s 17s 102s annealing (ta=22min) 0s 8.5s 34s 93.5s results Pressure Quench

  16. results relaxation of orientation experimental theoretical (tube model)

  17. results relaxation of orientation experimental theoretical (tube model) For HMW tail (1,480,000 g/mol) at 134 oC Long lifetime of orientation Besides molecular mobility, other effect exists.

  18. results relaxation of orientation theoretical (tube model) For HMW tail (1,480,000 g/mol) at 134 oC iPP[1] Long lifetime of orientation Besides molecular mobility, other effect exists. [1] H An et al. J. Phys. Chem. B 2008, 112, 12256

  19. results relaxation of orientation theoretical (tube model) For HMW tail (1,480,000 g/mol) at 134 oC iPP[1] Long lifetime of orientation Interaction between PE chains (or segments) at 134oC [1] H An et al. J. Phys. Chem. B 2008, 112, 12256

  20. results average nuclei density specific (200) diffraction (equatorial, off-axis or meridional) no annealing annealing (ta=22min) randomization of c-axes content of twisting overgrowth (nuclei density)

  21. results average nuclei density specific (200) diffraction (equatorial, off-axis or meridional) no annealing annealing (ta=22min) randomization of c-axes content of twisting overgrowth (nuclei density) some nuclei relax within annealing lower nuclei density

  22. results Pressure Quench with annealing (ta=22min) orientation 0s 8.5s 34s 93.5s kinetics – apparent crystallinity Using Pressure Quench, it is found that nuclei orientation survives but average nuclei density decreases within annealing. Z Ma et al. to be submitted

  23. results flow field in the slit X-ray WAXD results after flow the whole sample in situ characterization  the first formation outer layer (strongest flow)

  24. objective observable point-like nuclei No row nuclei -- No oriented nuclei formation during flow shish nuclei – Yes

  25. experimental combining rheology (Multi-pass Rheometer ,MPR) and X-ray Pilatus MPR DUBBLE@ESRF (30 frame/s) to track shish formation during flow

  26. experimental combining rheology and X-ray X-ray Pilatus MPR DUBBLE@ESRF flow time 0.25s (30 frame/s) Pressure difference and shish during flow

  27. For ≥ 240 , pressure difference deviates from the steady state and shows an “upturn”. results rheology “upturn”  wall stress iPP (HD601CF) at 145oC

  28. results rheology birefringence 0.03 MPa iPP (PP-300/6) at 141oC[1] iPP (HD601CF) at 145oC approach steady state after start-up of flow [1]G Kumaraswamy et al Macromolecules 1999, 32, 7537

  29. results rheology birefringence “upturn”[1] “upturn” 0.06 MPa  oriented precursors iPP (PP-300/6) at 141oC[1] iPP (HD601CF) at 145oC ∆P “upturn”  precursory objects form faster at higher shear rate [1]G Kumaraswamy et al Macromolecules 1999, 32, 7537

  30. results apparent shear rate of 400s-1 and T = 145oC 1). formation of precursor flow ∆P “upturn”  precursors during flow. time for precursor formation is around 0.1s

  31. shish streak results apparent shear rate of 400s-1 and T = 145oC 2). from precursor to shish 2D SAXS time 0.10s 0.20s 0.23s flow stops at 0.25s 0.26s 0.40s

  32. results apparent shear rate of 400s-1 and T = 145oC 2). from precursor to shish SAXS 2D SAXS flow flow shish SAXS equatorial Intensity shish formation around 0.23s

  33. results apparent shear rate of 400s-1 and T = 145oC rheological response SAXS flow flow shish formation around 0.23s ∆P “upturn” around 0.1s Precursors develop into shish

  34. results apparent shear rate of 560s-1 and T = 145oC t = 0.13s t = 0.17s shish t = 0.20s Shish forms during flow, faster at 560s-1 than 400s-1.

  35. results apparent shear rate of 320s-1 and T = 145oC t = 0.26s t = 0.33s shish t = 0.37s Shish precursors form during flow and shish forms after flow.

  36. results SAXS results linked to the FIC model Nucleation and growth model[1] growth rate number of nuclei length growth total length of shish [1] F. Custodio et al. Macromol. Theory Simul. 2009, 18, 469

  37. conclusions conclusions innovation observable point-like nuclei Suspension-based model • The combined effect of nucleating agent and flow on the nucleation density can be assessed. No Pressure Quench • Formation of row nuclei is visualized. • Stable nuclei can survive within 22-min annealing. • Unstable ones relax within 22-min annealing. row nuclei -- No oriented nuclei Combining rheology and synchrotron X-ray • Shish formation is tracked during flow. • The shish precursors are formed during flow and further develop into shish. • Formation times of shish precursors and shish both depend on the flow conditions. shish nuclei – Yes

  38. Acknowledgements Prof. Gerrit Peters Dr. Luigi Balzano Ir. Tim van Erp Ir. Peter Roozemond Ir. Martin van Drongelen Dr. Giuseppe Portale

  39. Thank you for your attention

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