micro-scale polymer processing: multiscale modelling of entangled polymers

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  • Slide 1
  • Micro-scale Polymer Processing: Multiscale Modelling of Entangled Polymers
  • Slide 2
  • Polymer Processing in the 21st century? Reaction Chemistry Molecular shape Good processing Melt Rheology
  • Slide 3
  • Industrial LCB and the Buffer Zone THEORYMODEL MATERIALS INDUSTRIAL RESINS
  • Slide 4
  • Polymer characterisation Synthesis Scale up Advanced Rheological Characterisation Model Processing Flow Rig Materials testing Solid state Modelling Flow computation Molecular Theory Molecular Configuration Probes Synthesis Rheology Processing Properties INDUSTRY The Scaffold Concept
  • Slide 5
  • Follow the processing path of well characterised polymers from synthesis through processing and property evaluation combined with the parallel development of a mathematical and computational protocol. Polymer characterisation Synthesis Scale up Advanced Rheological Characterisation Model Processing Flow Rig Materials testing Solid state Modelling Flow computation Molecular Theory Molecular Configuration Probes The Principle
  • Slide 6
  • The Team Leeds Tom McLeish, Oliver Harlen, David Groves, Alexei Likhtman, Tim Nicholson, Alan Duckett, John Embery, Jorge Ramirez, Chinmay Das, Harley Klein, Dietmar Auhl Bradford Phil Coates, Tim Gough, Mike Martyn, Rob Spares Durham Lian Hutchins, Nigel Clarke, Eduardo de Luca Sheffield Tony Ryan, Ellen Heeley, Patrick Fairclough, Ron Young, Christine Fernyhough Cambridge Malcolm Mackley, Karen Lee, Ashish Lele, Mark Collis, David Hassell Oxford Paul Buckley, Junjie Wu, David de Foccatis
  • Slide 7
  • Polymer characterisation Synthesis Scale up Advanced Rheological Characterisation Model Processing Flow Rig Materials testingSolid state Modelling Flow computation Molecular Theory Molecular Configuration Probes flowSolve Tube models: LCB: Pom-Pom linear: ROLIEPOLY Cambridge MPR4/ Bradford-Durham recirc. Durham SANS Sheffield SAXS hPS+dPS linears +3 blends PB combs PB linears + hPB variants G *, shear transients, step shear Mei ner extensional Ox ford Model Compression Craze Birefringence Outline
  • Slide 8
  • Synthesis Platform Make polybutadiene in controlled fashion Polydispersity < 1.05 Molecular weight determined by reagent quantities Micro-structure affected by temperature, solvent Then hydrogenate to make polyethylene
  • Slide 9
  • Update on tube model physics: Reptation + Contour Length Fluctuation + Constraint Release Molecular Theory Platform
  • Slide 10
  • Reptation +CLF flow CR retraction Detailed Chain Formulation Graham, Likhtman, Milner, TCBM s R(s)
  • Slide 11
  • log [s -1 ] log G, G [Pa] Linear shear rheology and predictions PP2 software tool: RepTate Lines are predictions from linear theory (Likhtman & McLeish 2002) Model Parameters from linear theory: (Likhtman & McLeish 2002) e (25C) = 0.003 s G e (25C) = 0.569 MPa M e = 4.86 kg/mol c v = 0.1 T ref. = 25 C PI-4kPI-14kPI-30kPI-90kPI-200k
  • Slide 12
  • Solve momentum and mass conservation equations: where is the polymeric stress Flow solving Platform Constitutive equation can be used to calculate polymer stress. Develop a Lagrangian finite element flow solver whose moving triangular grid elements can hold the constitutive parameters (orientation and stretch for each mode). b, s,S, => u,p Nicholson, Bishko, Harlen
  • Slide 13
  • flowSolve output planar flow The recirculating vortex in the corner grows considerably as the simulation proceeds. The maximum stretch is not along the centre line, but lies between the centre line and the recirculating region where the material is sheared prior to extension.
  • Slide 14
  • MuPP2 Structure A Matrix approach to Industrial demand and technical opportunity
  • Slide 15
  • MuPP2 Management + Special task groups: Rheology team Synthesis team Solid State team Flow solving software team PDRA conference
  • Slide 16
  • EXPERIMENTAL DATA Text, binary file *.txt, *.dat, *.out ToolBox Need to visualize DIFFERENT VIEWS Gnuplot, Origin, Excel, Matlab, Xmgr THEORIES ReptationCLF DTDCCR SCCRRolie-Poly .Pom-Pom Set of equations to solve. Program in C, Fortran, C++, Pascal, Maple, Matlab, Mathematica Need to compare
  • Slide 17
  • 2PHASE: Mesoscale Simulations Two-dimensional simulations of freely suspended particles in a polymeric fluid under shear flow. Biperiodic lattice to extend a unit cell containing N particles to an infinte domain. Under shear these cells slide relative to one another. O. Harlen and A. Malidi
  • Slide 18
  • CRYSTAL Shear-induced crystallization of comb 10 363K 1020 s sheared at 100 s -1 for 5 s prior to crystallisation Massively increased rates after shear Well oriented crystals (no shearing during crystallisation) 54 kg mol -1 backbone with 8 arms of 15 kg mol -1 No shear
  • Slide 19
  • Model materials refine new entanglement physics Molecular structure has flow-field consequences Chain orientation is a family of numbers Routes to Polydisperse architectures Methodology extends to product structure in phase and crystallinity. Conclusions

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