1

“Inventing Plastic Microcapillary Films”

BY

MALCOLM MACKLEY.With Acknowledgement to;

Dr Bart HallmarkDr Christian Hornung

Dora MedinaSina Bonyadi and Hui Cheah

Nuno ReisFrederik Scheiff, David Agar and Matthais Mendorf

DEPARTMENT OF CHEMICAL ENGINEERING AND BIOTECHNOLOGY.

UNIVERSITY OF CAMBRIDGE.

mrm5@cam.ac.uk

LG. Korea 2012

2

Plastic Fantastic

Sub millimetre Process Engineering

3

Plastication of polymer

Band heaters

hopper

high pressure gas

metering device

static mixer nucleationPolymer

Polymer/gas solution formation

Nucleation and Cell growth

plasticating screw

Conventional Foaming Processing

4

Background. Plastic Micro Capillary Films

(MCFs)

Bart Hallmark and Malcolm Mackley 2005

5

6

Haul off

Hollow extrudate

Heatedbarrel

Gear pumpT1 T2 T3 T4

T5 T6Motor

Hopper

Screw

Flange with filter

P2

Nitrogen supply

Gas flow control

Primary pressureregulator

Secondary pressureregulator

F

Rotameter

Die

T7

P1

Gas injector

Convergent die

Edge of quartz window

Early experiments 2002

PE

7

Heatedbarrel

Gear pumpT1 T2 T3 T4

T5 T6Motor

Hopper

Screw

Flange with filter

P2

Die

T7

P1

Haul off

Hollow extrudate

Gas entrainment

Convergent die

Edge of quartz window

MCF Process Development

Hallmark et al. J. Non-Newtonian Fluid. Mech (2005)

8

Quench bath

Melt drawing length, L

Extrudate to haul off

Polymer flow

Die land

MCF extrudate

Brass ‘roller’

Gas entrainment – die and injector design

9

Low voidage MCF

10

Die design

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T1 T2 T3 T4

T5 T6P2

Single screw extruder

MCF extrusion

die

Chilled rollers

Spooling

Guide rollers

Gear pump

MCF

PLAN VIEW

MCF

Chill rollers

Direction of flow

Array of 19 entrainment nozzles

Entrainment body

Air inlet

Polymer melt

Die exit

Quenching length, L

The MCF process

Hallmark et al Adv. Eng. Mat., (2005).

12

A1

A2 A3

1

322 A

AA

31

21 AA

A

= 9.6 %

= 10.3%

Initial die voidage

13

Low Voidage MCF

Standard MCF

0

50

100

150

200

250

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

Capillary number

Hyd

rau

lic d

iam

eter

(μ

m)

340 μm

MCF voidage ≈ 9-11 %

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Drawing Low Voidage MCF

D. I. Medina B. Hallmark T. D. Lord M. R. Mackley The development of voidage and capillary size within extruded plastic films. J Mat Sci, in press

15

MCF

Fixedlowerclamp

Upper Clamp

Mechanical Drawing of MCFs (using stable Microsystems texture analyser)

MCF

Upper Clamp

Fixedlowerclamp

RoomTemperature

Mechanical drawing process - Increases orientation but limits drawability

16

Diameters after Mechanical Drawing of MCFs

0102030405060708090

100110120130140150160170180190200210

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Capillary number

Hyd

rau

lic d

iam

eter

(μ

m)

Standard MCF

Diameters after Mechanical Drawing

17

COLD DRAWN

0

20

40

60

80

100

120

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

Capillary number

Hyd

rau

lic d

iam

eter

(μ

m)

MCF voidage ≈ 8.5 %

Necking

Post-neckmaterial

Material in neck

Undrawn material

18

0

5

10

15

20

25

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

Capillary number

Hyd

rau

lic

dia

met

er (

μm

)

HOT DRAWN

MCF voidage ≈ 9-11 %

Optic micrograph of top view MCFs

Drawing direction

19

V2

Extrusion die

Chilled rolls 9 °C

Hot roll T = 60-120°C

MCF

Quenching

Extruder

Hot drawing - Second stage Hot draw-

Molecular orientation

Melt T=170 °C

little

orie

nta

tion

Hig

h o

rien

tatio

n

V1

Draw ratio λ = V1/V2

Solid

Thermal camera image

X-Ray diffraction

20

MCF Product from continuous drawing

Optic micrograph of top view MCFs

100 μm

Drawing direction

0

20

40

60

80

100

120

140

160

180

200

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Capillary number

Hyd

rau

lic

dia

met

er (

μm

)

21

High Voidage MCF

D Medina J Mat Sci 2008

22

T1 T2 T3 T4

T5 T6P2

Compressed air

Isolationvalve

Conventional extrusion line MCF extrusion die

Chilled rollers

High-speed air quench

Needlevalve

Mass flow control valve

Spooling

Guide rollers

TP P

P Pressure sensor

T Temperature sensor

Manual valve

Control valve

High Voidage MCFsBy rapid cooling and or injecting air under pressure into capillaries during melt processing it is possible to produce “High voidage MCFs”

Develop orientation

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High voidage MCFs

100 μm

MCF-MCF hv2- big voidage

0

50

100

150

200

250

300

350

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

Capillary number

Hyd

rau

lic

dia

met

er (

μm

)

200 m

Hydraulic diameter varies from 150 μm to 417 μm

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(110)

(200)

Orientation present

X-Ray

Extrusion direction

Solid MCF

Air entrainmentneedle

SolidificationInterface zone

Die exit

Air quench jet

Air quench jet

MoltenMCF Chill rollers

Extrusion direction

Solid MCF

Air entrainmentneedle

SolidificationInterface zone

Die exit

Air quench jetAir quench jet

Air quench jetAir quench jet

MoltenMCF Chill rollersChill rollers

Melt residence time << 1 sMelt relaxation time < 1 s

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Extrusion direction

Solid MCF

Air entrainmentneedle

Solidificationinterface

Die exit

Air quench jet

Air quench jet

MoltenMCF

Chill rollers

To << Ti

ηo

ηi

To

Ti

u1A1, u2A2,

ηo >> ηi

High-voidage MCF

Asymmetry in temperature profile Asymmetry in viscosity profile Asymmetry in the velocity profile

Symmetry planeInjector needle

2D schematic

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Ultra High Voidage MCF

D. I. Medina B. Hallmark T. D. Lord M. R. Mackley The development of voidage and capillary size within extruded plastic films. J Mat Sci, in press

27

MCF

Fixedlowerclamp

Upper Clamp

Mechanical drawing of High Voidage MCFs

Capillary direction

MCF

Upper Clamp

Fixedlowerclamp

RoomTemperature

It breaks

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Upper Clamp

MCF

Fixedlowerclamp

MCF

Fixedlowerclamp

Upper Clamp

Mechanical drawing of MCFs Transverse direction

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HV-MCF is unfolded to form

the UHV-MCF

Dora Medina

Go to MCF UHV movie

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ULTRA HIGH VOIDAGE MCFs

1000 μm

1000 μm

1000 μm

SEM UHV-MCF

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High Voidage die

Bart Hallmark 2008

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A1

A2 A3

1

322 A

AA

31

21 AA

A

= 30%

= 60%

Initial die voidage

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High Voidage Die – some interesting results

Melt draw, chill rollers, haul off

Die quench, haul off

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Microcapillary Monoliths

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An addition to the MCF family – Microcapillary Monoliths (MCMs)

500μm

200μm

7mm

Christian Hornung

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Plastic Fantastic

MCF applications

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MCF Development; Pressure Drop

Christian Hornung

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MCF Development RTD

0

5

10

15

20

25

30

35

40

45

50

0 5 10 15 20 25 30t [min]

c [m

g/l]

inletoutlet

length = 20 mflow rate = 0.5 ml/min

PE, EVOH and FEP

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MCF Commercialisation

2 flat silicon heaters (200 W each) PID control - Temperature monitoring at top and bottom heater

plates

Tmax = 150 °C developed by

Lamina Dielectrics Ltd.& Cambridge University

Teflon coatedhot plates

Temperature control

Reactor disk tray

Patrick Hestor Lamina Ltd

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MCF Development; Microflow

Organic.Kerosene, 1.8 mPasOil, 27 mPasVegetable oil. 50 mPas

Water, 1 mPas, glycerol 10-50 mPas or methanol

Video,Methanol into Veg oil

Nuno Reis

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MCF Development; Slug separation

Scheiff et al. Lab on a Chip. 2011

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Multi channel flow

Nuno Reis

Go to MCF multi channel flow

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MicrocapillaryFlow disc

Vegetable oil

Glycerol

Biodiesel

Methonal pluscatalyst

Input Output

MCF Development; Biodiesel Microreactor

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MCF Microreactor; BiodieselMethanol

Veg oil

Methanol pluscatalyst

Glycerol

Glycerol

Biodiesel

45A Edwards et al Lab on a Chip 2011

MCF Protein Assay Nuno Reis and Al Edwards

FEP/EVOH

46

Bore fluid

NitrogenGas

Cylinder

Polymer Solution

Die

External Coagulant

Haul-off

Single Capillary,MCF membranes

Air-gap

Glass Water Bath

MCF Development. Microporous MCF membranes

Sina Bonyadi

PVDF/NMP (18/82 wt%)

47

Water coagulation

bath

Bore Fluid

Polymer Solution

Air-gap

MCF Membrane Fabrication Concept

48

Microporous MCFs

2 µm

100 µm

2 µm

1 µm

Bonyadi et al. Journal of Membrane Sci 2012

49

Plastic Fantastic

Microcapillary Films (MCFs)

•Polymer processing lessons learnt.

•A new material form looking for the right application.