micro-scale polymer processing: multiscale modelling of entangled polymers

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Micro-scale Polymer Processing: Multiscale Modelling of Entangled Polymers

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Page 1: Micro-scale Polymer Processing: Multiscale Modelling of Entangled Polymers

Micro-scale Polymer Processing:Multiscale Modelling of Entangled Polymers

Page 2: Micro-scale Polymer Processing: Multiscale Modelling of Entangled Polymers

Polymer Processing in the 21st century?

Reaction Chemistry

Molecular shape

“Good processing”

Melt Rheology

Page 3: Micro-scale Polymer Processing: Multiscale Modelling of Entangled Polymers

Industrial LCB and the “Buffer Zone”

THEORY MODEL MATERIALS INDUSTRIAL RESINS

18 20 22 24 26

0.0

0.2

0.4

0.6

0.8

1.0

RI

(rel

ativ

e in

ten

sity

)

Retention time (minutes)

DOW680E 200k before 200k after

103

104

105

106

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2Model distribution for CM3

MW

Fre

quen

cy

102

104

106

108

10-4

10-1

102

105

108

G'(

), G

''()

0

2

4

6

-5 0 5 10

log

log

G'(

), G

''()

Page 4: Micro-scale Polymer Processing: Multiscale Modelling of Entangled Polymers

Polymer characterisation

Synthesis Scale up

Advanced RheologicalCharacterisation

Model ProcessingFlow Rig

Materials testingSolid stateModelling

Flow computation

Molecular Theory

Molecular ConfigurationProbes

Synthesis

Rheology

Processing

Properties

INDUSTRY

The Scaffold Concept

Page 5: Micro-scale Polymer Processing: Multiscale Modelling of Entangled Polymers

• “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 RheologicalCharacterisation

Model ProcessingFlow Rig

Materials testingSolid stateModelling

Flow computation

Molecular Theory

Molecular ConfigurationProbes

The Principle

Page 6: Micro-scale Polymer Processing: Multiscale Modelling of Entangled Polymers

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

Page 7: Micro-scale Polymer Processing: Multiscale Modelling of Entangled Polymers

Polymer characterisation

Synthesis Scale up

Advanced RheologicalCharacterisation

Model ProcessingFlow Rig

Materials testingSolid stateModelling

Flow computation

Molecular Theory

Molecular ConfigurationProbes

flowSolve

Tube models:LCB: Pom-Pomlinear: ROLIEPOLY

Cambridge MPR4/Bradford-Durham recirc.

Durham SANSSheffield SAXS

hPS+dPS linears +3 blendsPB combs PB linears + hPB variants

G*, shear transients, step shearMeiner extensional

Ox ford ModelCompressionCrazeBirefringence

Outline

Page 8: Micro-scale Polymer Processing: Multiscale Modelling of Entangled Polymers

Synthesis Platform

• Make polybutadiene in controlled fashion

sec-Bu-Li+ +

1,4-polybutadiene (cis- and trans-)

1,2-polybutadiene

93%

7%

n

m

-

Li+

– Polydispersity < 1.05– Molecular weight determined by reagent quantities– Micro-structure affected by temperature, solvent

• Then hydrogenate to make polyethylene

Page 9: Micro-scale Polymer Processing: Multiscale Modelling of Entangled Polymers

Update on tube model physics:Reptation + Contour Length Fluctuation + Constraint Release

Molecular Theory Platform

Page 10: Micro-scale Polymer Processing: Multiscale Modelling of Entangled Polymers

)','(ln'

)',('

),(ln)',(2

1

)('2

3)(

')',(

'

2

2

2

2

2

ssftrs

ssfs

ssftrs

ssfs

ffss

ffffss

ssDsst

f

e

eqT

eq

)','(ln'

)',('

),(ln)',(2

1

)('2

3)(

')',(

'

2

2

2

2

2

ssftrs

ssfs

ssftrs

ssfs

ffss

ffffss

ssDsst

f

e

eqT

eq

Reptation +CLF flow CR

retraction

Detailed Chain FormulationGraham, Likhtman, Milner, TCBM

zdsssf

s

tsR

s

tsRtssf

0),(;

'

),'(),(),',(

z

dsssfs

tsR

s

tsRtssf

0),(;

'

),'(),(),',(

s

R(s)

Page 11: Micro-scale Polymer Processing: Multiscale Modelling of Entangled Polymers

Log(w)43210-1-2-3-4

Lo

g(G

'(w

),G

''(w

))

7e0

6e0

5e0

4e0

3e0

2e02

taue=0.0030221

5.756 Ge=5.6985E5

log [s-1]

lo

g G

‘, G

‘‘ [

Pa

]Linear shear rheology andpredictions

µPP2 software tool: RepTate

Lines are predictions from linear theory (Likhtman & McLeish 2002)

Model Parameters from linear theory:(Likhtman & McLeish 2002)

e (25°C) = 0.003 s

Ge (25°C) = 0.569 MPa

Me = 4.86 kg/mol

cv = 0.1

Tref. = 25 °C

PI-4kPI-14kPI-30kPI-90kPI-200k

Page 12: Micro-scale Polymer Processing: Multiscale Modelling of Entangled Polymers

• 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).

2u p

u 0

b,s,S,=>

u,p

u,pu,p

Nicholson, Bishko, Harlen

Page 13: Micro-scale Polymer Processing: Multiscale Modelling of Entangled Polymers

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.

Page 14: Micro-scale Polymer Processing: Multiscale Modelling of Entangled Polymers

MuPP2 Structure

A Matrix approach to Industrial demand and technical opportunity

Platform I: Synthesis and Characterisation

Platform II: Theoretical Molecular Modelling

Platform III: Experimental Probes

Platform IV: Flow Visualisation

Platform V: Solid State Properties

Stm1: CRYSTAL Stm2: TOOLBOX Stm3: 2-PHASE

Page 15: Micro-scale Polymer Processing: Multiscale Modelling of Entangled Polymers

MuPP2 Management

+ Special task groups:• Rheology team• Synthesis team• Solid State team• Flow solving software team• PDRA conference

Page 16: Micro-scale Polymer Processing: Multiscale Modelling of Entangled Polymers

EXPERIMENTAL DATA

Text, binary file*.txt, *.dat, *.out…

ToolBox

Need to visualize

w0.001 0.01 0.1 1 10 100 1,000

G'(

w),

G''(w

)

1e2

1e3

1e4

1e5

1e6DIFFERENT

VIEWS

Gnuplot, Origin, Excel, Matlab, Xmgr…

THEORIES

Reptation CLFDTD CCRSCCR Rolie-Poly…. Pom-Pom

Set of equations to solve.Program in C, Fortran, C++, Pascal, Maple, Matlab, Mathematica…

Need to compare

Page 17: Micro-scale Polymer Processing: Multiscale Modelling of Entangled Polymers

2PHASE: Mesoscale SimulationsTwo-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

Page 18: Micro-scale Polymer Processing: Multiscale Modelling of Entangled Polymers

CRYSTALShear-induced crystallization of comb 10

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00

1.10

1.20

0 200 400 600 800 1000 1200 1400

Time /sec

No

rmal

ised

inte

nsi

ty /A

rb

363K iso

368K iso

363K shear

368K shear

370K shear

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

Page 19: Micro-scale Polymer Processing: Multiscale Modelling of Entangled Polymers

• 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