Progress in RegeneratedCellulose Fiber Production

Workshop on Cellulose Dissolution and regeneration,Göteborg, December 3rd, 2013

Herbert SixtaDepartment of Forest Products Technology, Aalto University, Finland.

Research team

AALTO UniversitySenior scientist:– Dr. Michael Hummel

PhD students:– Lauru Hauru– Anne Michud– Shirin Asaadi

Textile design– Marjaana Tanttu

Helsinki UniversityProfessor– Ilkka Kilpelainen

Senior scientist:– Dr. Alistair King

PhD students:– Arno Parviainen– Ashley Holding– Tia Kakko

Outline

Cellulose dissolution andregeneration

Spinning at AALTO

Structure Formation

Regenerated CelluloseProcesses

Background

Composites

Market of Cellulose Products

4

The Fiber Year 2013: World Survey on Textiles`& Nonwovens, April 2013

Global textile market- Cotton stagnant at 26-28 Mio t/a- High cotton prices- 33-37% minimum share of

cellulosics in textiles- GAP of 15 Mio t/a of cellulosic

fibers in 2030

Growth rates- Viscose, Lyocell > 9%/a- Acetate 1.5%/a

1940 1960 1980 2000 20200

2

4

6

8

10 MMC staple fiber, Mio t/a

1940 1960 1980 2000 20200

2

4

6

8

10 MMC staple fiber, Mio t/a

6%

9%

6%

Textile Fibers Overview

WoolSilkAngoraCashmereothers

CottonFlaxJuteHempOthers

ViscoseModalLyocellCuproAcetate

CaseinCollagenArdeinZein

PolyesterPolyamideElastanPPPUAcrylPET

CarbonCeramicsGlassMetal

Cellulosebased(MMC)

Protein-based

Cellulosebased

Protein-based

Natural fibersFrom natural

polymersSyntheticpolymers

Inorganiccompounds

Man-made fibers

FIBERS

Eichinger, Lenzing AG, 2012

Textiles value chain

Apparel– Silkiness– Soft drape– Good moisture absorption– skin sensory

characteristics– Lingerie

Spinning Yarn Knitting&Weaving

Dyeing &Finishing

GarmentManufact Retail CustomerFiber

Producer

Hometextiles:– Mattresses– Mattress pads– Upholstery– Carpets

Lenzing AG, 2013

Nonwovens

WipesHygiene

– Tampon fibersMedical

– Plasters– Wound pads– Surgical swabs, drapes and gowns

Technical– Filtration– Papers (short cut fibers)– Battery separators– Precursor fibers (carbon, graphite ,..fibers)

Roll-goodproducer

Converter

Privatelabel orbrand

Retailer CustomerFiberProducer

Lenzing AG, 2013

Outline

Cellulose dissolution andregeneration

Spinning at AALTO

Structure Formation

Regenerated CelluloseProcesses

Background

Composites

ViscoseCS2/NaOH

CarbamateNaOH/urea in o-

xylene *

BioCelsolEnzyme/NaOH/ZnO

(urea/thiourea)

BoCellSuperphosphoric acid

Air gap / acetone regen

MichelinFormate/air

gap/saponified

DuPontAcetate in

TFA/HCOOH/steamdrawn/saponified

FortisanAcetate/acetonespun, saponified

Cupro[Cu(NH3)4](OH)2

LYOCELL(a) NMMO.MH(b) Ionic liquids

*CarbaCell®Commercial, now or in former timesNon-commercial

Viscose vs. Lyocell

10Andrzej Ziabicki, Fundamentals of fiber spinning, John Wiley & Sons Ltd, (ISBN: 0-471-98220-2).

Viscose Lyocell

NaOH / CS2

wet spinning dry-jet wet spinning

derivatization direct dissolution

wood pulp

Viscose, Lyocell

Global production, 2012: 3.7 Mio tGlobal capacity, 2012: 5.2 Mio t

Cotton ViscoseModal Lyocell

Cellulose is converted to a cellulose xanthate which is thendissolved in diluted caustic.o CV: Regular Viscoseo CMD: Modal Fibres are high wet modulus fibres produced by a

modified viscose process: Bisfa wet modulus > 5 cN/tex/5%o CLY: Lyocell, Tencel®: air-gap spun from solution in direct solvent

Untersberger, CEO Lenzing AG, 2013

Historic viscose fiber developments

Process DP pulp Celluloseconc, %

CS2charge, %

Spinbath Stretch-ability,

%

Modifiers X-raycrystal-linity, %

Accessibility, %

(H/D)

Td,cN/tex

Tw,cN/tex

Standard 350-450 8-9 26-32 High acidity, highNa2SO4,

moderate ZnSO4

50-70 No or low amount ofmodifiers

28-35 65 25 12

High-wetmodulus

500-550 6 35-40 Moderate acidityand Na2SO4, high

ZnSO4

80-150 Organic modifiers(amines, PEOs)

35-40 50 35 20

Polynosic 600-650 6 38-42 Weakly acidic,strongly

coagulating saltbath.

Second, moreacidic bath

200-300(max600)

Addition offormaldehyde to

form methylolgroups, which are

split off in thesecond bath

40-47 45 35-55 25-35

Outline

Cellulose dissolution andregeneration

Spinning at AALTO

Structure Formation

Regenerated CelluloseProcesses

Background

Composites

Cellulose dissolution

Cellulose is amphiphilic (structural anisotropy): containspolar in equatorial and nonpolar groups in axial directions->electrostatic repulsion between charged backbones prevents re-association (Zn[OH]4

2-]

Thermodynamic aspects: hydrophobic interactions, 2.0 kcal/mol/residue, H-bonding, effect of charges

Kinetic aspects: removal of primary cell wall structure facilitatesthe penetration of the solvent molecules into internal cellulosestructure->ballooning phenomena avoided

• Martin Kihlman et al. Braz. Chem. Soc., Vol. 24, No. 2, 295-303, 2013• Medronoh, B.; A. Romano; M.G. Miguel; L. Stigsson; B. Lindman. Cellulose (2012), 19, 581-587• Bergenstråhle,M.; J.Wohlert, ME Himmel, JW Brady. Carbohydr Res (2010), 14, 2060-2066• Le Moigne, N.; Navard, P. ACS Symposium Series (2010), 1033 (Cellulose Solvents), 137-148.

Dissolution of Cellulose in ILs

+

+

O3-H-O5 intrachainO2-H-O6 intrachainO6-H-O3 interchain

O3-H-O5 intrachainO2-H-O6 intrachainO6-H-O3 interchainintersheet H-bondIntersheet bonds

+

O3-H-O5 intrachainO2-H-O6 intrachainO6-H-O3 interchainintersheet H-bond

Cho, H.M.; Gross, A; Chu J.-W. J. Am. Chem. Soc. 2011, doi 10.1021/ja2046155.

Solvation of nonpolar cellulose surfaceby the cation

Regeneration of cellulose

+ H2O

O3-H-O5 intrachainO2-H-O6 intrachainintersheet H-bond

Liu, H.; Sale, K.L.; Simmons, B.A.; Singh, S. Phys. Chem. B 2011, 115, 10251–10258.

Re-formation of intersheet and intrachainbonds

Wood pulp

IL / H2O

Final dope has to be filtrated and degassed

0 30 60 90 1200

50

100

150

Tem

pera

ture

,C

Time, min0

200

400

600

Torq

ue,N

mdissolved

Cellulose dissolution in a vertical kneader

19

Solubility up to 20 wt%PHK-Pulp, [ ] = 424 mL/g

20

0 s

45 s

Euca Sulfite DWP

Complete dissolution by left handeduntwisting of cellulose fibrils

Euca Kraft-CCE100

Increased swelling, no dissolutionBallooning, formation of collars

Gehmayr, V., Potthast, A., H. Sixta, Cellulose (2012)

Dissolution mechanismIn Cupri ethylendiamine

Swelling & Dissolution mechanisms:1. Dissolution by fragmentation2. Dissolution by ballooning3. Swelling by balloning4. Homogeneous swelling

Cuissinat, C.; Navard, P. Macromol Symp (2006), 244, 1-18Le Moignet, N.; Navard, P. ACS Symposium Series 1033 (2010), 137

Influence of Cell Wall Structure1. Solvent penetrates inside the fiber2. The S2 layer dissolved by fragmentation3. The S1 layer swells under pressure4. The primary wall breaks to form collars

21

Cellulose Aggregate Solution

0

50

100

150

200

250

no water20% NaOH

liquid ammonia0

200

400

600

800 Rg ,radius

ofgyration,nmaggr

egat

enu

mbe

r*

pre-treatment

*MW/162 DP

T. Röder, B. Morgenstern, Polymer 40 (1999) 4143 - 4147

0.2-0.3 wt% Pulp dissolved in NMMO.MH

Static light scattering measurements (Guinier-Zimm)

Molecules laterally aligned,core surrounded bydisordered regions;aggregate size not affected

Interpenetrated networksolution

Cellulose Dissolution&Regeneration in Water

Dissolution of Euca-PHK in:– [EMIM]OAc– [TMGH]OAc– [TMGH]EtCOO– NMMO H2O

• Regeneration by addition of water and mixing

• On completion of regeneration, turbidity appearsover a range

Hauru, L.K.J.; Hummel, M.; King, A.W.T.; Kilpeläinen, I.; Sixta, H. Biomacromolecules 2012, 13, 2896-2905..

23

Empirical Kamlet Taft solvent descriptorspredict cellulose solubility

Hauru, L.K.J.; Hummel, M.; King, A.W.T.; Kilpeläinen, I.; Sixta, H.Biomacromolecules 2012, 13, 2896-2905.

Dissolution window• Correlation of KT-parameter *

with cellulose solubility• Concept of net-basicity, , to take

into account

0,0 0,3 0,6 0,9 1,2 1,5-1,0

-0,5

0,0

0,5

1,0

100

20

[emim]OAc [TMGH]EtCO2

[TMGH]OAc NMMO H

2O

NMMO 2H2O LiCl/DMAc [Pnnnn]

[Rmim]MeOHPO2

[eimH]EtCOO [DMAPH]EtCOO [HOC2mim] [emim] [bmim]

23

Effects on the UV–VIS spectra of dyesto probe particular solvent properties

N+

O-

Reichardt's dyegreen-blue in methanol

… hydrogen bond acidity (donor)… hydrogen bond basicity (acceptor)*…dipolarity/polarizability (ability of a solvent to

stabilize a charge or a dipole)

Empirical solvent descriptors are veryhelpful in the development of novelsolvents for the dissolution ofindividual lignocellulosic components

M.J. Kamlet and R.W. Taft: JACS, 98:2, 377-383 (1976)R.W. Taft and M.J. Kamlet: JACS, 98:10, 2886-2894 (1976)M.J. Kamlet, J-L.M. Abboud, MH: Abraham, R.W.Taft, JOGS, 48,2877-2887 (1983)

Effect of Water

0 2 445

48

51

54

0 2 4 60.8

0.9

1.0

1.1

1.2

0 2 40.0

0.2

0.4

0.6

0.8

0 2 4 6

0.6

0.8

1.0

1.2

ET(30) *

Stoichiometry, (n H2O)Stoichiometry, (n H2O)

[TMGH]EtCOO [TMGH]OAc [emim]OAc NMMO LiCl/DMAc

decreases almostlinearly.

Deviation of linearitydue to water activity(non-linear).

Similar slope fordifferent Ils.

values of NMMOhydrates more sensitiveto water (high enthalpyof hydration of NMMO).

Hauru, L.K.J.; Hummel, M.; King, A.W.T.; Kilpeläinen, I.; Sixta, H.Biomacromolecules 2012, 13, 2896-2905.

Cellulose Regeneration in Water

• Noticeable turbidityappears only when2 mol H2O/ mol IL arereached or exceeded.

• Slope of turbidity riseslower for [TMGH]-ILsthan for the referencesolvents.0 2 4 6 8 10

0

100

200

300

400 [EMIM]OAc [TMGH]EtCOO [TMGH]OAc NMMO

Turb

idity

(NTU

)

Stoichiometry (n H2O)

Hauru, L.K.J.; Hummel, M.; King, A.W.T.; Kilpeläinen, I.; Sixta, H.Biomacromolecules 2012, 13, 2896-2905.

26

Regeneration

Hauru, L.K.J.; Hummel, M.; King, A.W.T.; Kilpeläinen, I.; Sixta, H. Biomacromolecules 2012, 13,2896-2905. DOI:10.1021/bm300912y.

0,6 0,8 1,0 1,2

0,0

0,5

1,0

----------

----

--

----

--

----

----

--

--

------

--

-- LiCl/DMAc [TMGH]EtCO

2

[TMGH]OAc NMMO

lit. [emim]OAc

Dissolution vs Regeneration• decreases upon water addition.

• [emim][OAc] water-tolerant ~ 16 w/w%

• [TMGH]-ILs water-intolerant 1-4 w/w%

• [TMGH]+ hydrotrope, bulky, hydrophobic

• Order of water tolerance: [TMGH][OAc]

< [TMGH][EtCO2] << [emim]OAc

26

Structure formation

Extrusionvelocity

Take-up velocity

27

In a dry-jet wet fiber spinningprocess the fluid filament isdrawn in the air gap

Structure formation

• Orientation of cellulosepolymers due toextensional stress

• Solvent exchange

• Formation of fiber’smicrostructure

Crystallites

Laminas

Irregular moleculesarrangement

Draw

28

Fourné, Synthetic Fibers; Carl Hanser Verlag, Munich 1999.

Experimental details

29

H2O

Cotton linters: DP 1975 (729 ml/g)DP 2640 (909 ml/g)

Eucalyptus urograndis pulpDP 1100 (468 ml/g)

dissolution

wateraddition H2O

Nephelometry

0 10 20 30 40 50

0

50

100

150

200

250

300

350

Turb

idity

(NTU

)water (%)

Turbidity

0 10 20 30 40 50

0

50

100

150

200

250

300

350

Turb

idity

(NTU

)water (%)

Turbidity

0.1

1

10

100

Complex viscosity

Com

plex

visc

osity

[Pa·

s]

Mazza et al. Cellulose, 2009, 16, 207-215 (DOI: 10.1007/s10570-008-9257-x).

30

Turbidity measured byquantifying back-scatteredlight: Nephelometer

not sensitive enough!

Steady shear measurements

0.1 1 10 1001

10

100

1000

10000 0.0 %

Dyn

amic

visc

osity

[Pa·

s]

Shear rate [s-1]

0.1 1 10 1001

10

100

1000

10000 0.0 % 5.0 %

Dyn

amic

visc

osity

[Pa·

s]

Shear rate [s-1]

0.1 1 10 1001

10

100

1000

10000 0.0 % 5.0 % 7.3 %

Dyn

amic

visc

osity

[Pa·

s]

Shear rate [s-1]

0.1 1 10 1001

10

100

1000

10000 0.0 % 5.0 % 7.3 % 9.7 %

Dyn

amic

visc

osity

[Pa·

s]

Shear rate [s-1]

0.1 1 10 1001

10

100

1000

10000 0.0 % 5.0 % 7.3 % 9.7 % 10.4 %

Dyn

amic

visc

osity

[Pa·

s]

Shear rate [s-1]

0.1 1 10 1001

10

100

1000

10000 0.0 % 5.0 % 7.3 % 9.7 % 10.4 % 15.0 %

Dyn

amic

visc

osity

[Pa·

s]

Shear rate [s-1]

0.1 1 10 1001

10

100

1000

10000

Dyn

amic

visc

osity

[Pa·

s]

Shear rate [s-1]

31

5% cotton linters (DP 1975) in[emim][OAc]

• Solution is diluted uponwater addition

Steady shear measurements

0.1 1 10 1001

10

100

1000

10000

Dyn

amic

visc

osity

[Pa·

s]

Shear rate [s-1]

0.1 1 10 1001

10

100

1000

10000 15.3 %

Dyn

amic

visc

osity

[Pa·

s]

Shear rate [s-1]

0.1 1 10 1001

10

100

1000

10000 15.3 % 17.3 %

Dyn

amic

visc

osity

[Pa·

s]

Shear rate [s-1]

0.1 1 10 1001

10

100

1000

10000 15.3 % 17.3 % 19.2 %

Dyn

amic

visc

osity

[Pa·

s]

Shear rate [s-1]

0.1 1 10 1001

10

100

1000

10000 15.3 % 17.3 % 19.2 % 24.9 %

Dyn

amic

visc

osity

[Pa·

s]

Shear rate [s-1]

32

5% cotton linters (DP 1975) in[emim][OAc]

• Solution is diluted uponwater addition

• Gel formation, i.e. formationof a supramolecular networkstructure

• Structure collapses, phaseseparation

Rheological sample analysis

Rheological keyparameter as function ofwater content

Viscosity decreasesbefore a steep rise isobservedG’, G’’ depict similarbehavior

Damping factor ( ) mostsensitive parameter

33

0 10 20 30 40 501

10

100

1000

Com

plex

visc

osity

[Pa·

s]

Water (w/w-%)

Complex viscosity

0 10 20 30 40 501

10

100

1000

Com

plex

visc

osity

[Pa·

s]D

ynam

icm

odul

i[P

a]

Water (w/w-%)

Complex viscosity Storage modulus Loss modulus

0 10 20 30 40 501

10

100

1000

Com

plex

visc

osity

[Pa·

s]D

ynam

icm

odul

i[P

a]

Water (w/w-%)

Complex viscosity Storage modulus Loss modulus

0 10 20 30 40 501

10

100

1000

Com

plex

visc

osity

[Pa·

s]D

ynam

icm

odul

i[P

a]

Water (w/w-%)

Complex viscosity Storage modulus Loss modulus

0

2

4

Damping factor

Dam

ping

fact

or

3% cotton linters (DP 1975) in [emim] OAc

Outline

Cellulose dissolution andregeneration

Spinning at AALTO

Structure Formation

Regenerated CelluloseProcesses

Background

Composites

Spinning at AaltoIONCELL-F

[EMIM][OAc]/E-PHK 20 wt-%

• Textr. = 95ºC• Vextr. = 0.8 cm3/min

NMMO/H2O/E-PHK 13 wt-%

• Textr. = 100ºC• Vextr. = 0.8 cm3/min

UNSTRETCHED STRETCHED

Dry-wet jet spinning - preliminary tests

36

5 10 15 20

0,4

0,6

0,8

1,0 Tw/Td

Dope conc, wt%2 4 6 8 10

0

10

20

30

40

tena

city

[cN

/tex]

DR

[emim][OAc] (mono)6% 15%9% 20%

NMMO (multi 18/100)13 wt% E-PHK

Fiber properties

0,01 0,1 1 10 1001E+01

1E+02

1E+03

1E+04

13 wt% Eu-PHK inNMMOxH2O at 100°C

Dyn

amic

Mod

uli,

Pa

Angular frequency, 1/s

20 wt% Eu-PHK in[emim][OAc] at 95°C • Despite comparable rheology,

[emim][OAc] dopes are much moredifficult to spin than NMMO dopes

• Structure formation in spinbathdelayed. Weak filament breakswhen certain draw is exceeded.

• Slight increase in orientation withincreasing dope concentration.

Tailored ionic liquids for air-gap spinning

A series of novel ILs has been synthesized andcharacterized.All have high and net-basicity values ( - ) excellentcellulose solvents.

RTIL ET(30)(a) *[b] [b] [b] -[emim][OAc] 50.1 1.01 0.50 1.09 0.59

[emim][O2CEt] 50.3 0.96 0.54 1.09 0.56

IL-1 51.3 1.02 0.56 1.08 0.52

IL-2 52.6 1.04 0.64 1.11 0.47

IL-3 53.2 1.00 0.71 1.16 0.46

[a] Dimroth-Reichardt polarity scale, [b] Kamlet Taft parametersA. Michud, A. Parviainen et al. FIBIC poster, Aug 20-21, 2013

Pulpdissolution

Dopecharacterization

Fiberspinning Fiber analysisPulp

dissolutionDope

characterizationFiber

spinning Fiber analysis

pre-mixing kneading/dissolution filtration

Pulpdissolution

Dopecharacterization

Fiberspinning Fiber analysis

shear-rheological characterization(to determine spinnability)

extensional-rheological characterization(to determine filament stability in air gap)

0 50 100 150 2000,0

0,5

1,0

150 160 170

0,02

0,1 elasto-capillaryregion

time (sec)

elasto-capillary

diameter (mm)

time (sec)

visco-capillary region

0,1 1 10 100101

102

103

104

105

IONCELL

8.1x102

5.6x104

Dyn

amic

mod

uli[

Pa]

Com

plex

visc

osity

[Pa.

s]

Angular Frequency [1/s]

G' G''

*

10 wt% BahiaPulp, 60ºC

3.4x105 IL2

Dope characteristics Value

22.1 nm

54.1 nm

10.00.33 wt%

6.93.8 wt%

= 1 6

=

( )

=

= 2 0.01

13 wt% E-PHK in IONCELL

41

Pulpdissolution

Dopecharacterization

Fiberspinning Fiber analysis

Pulpdissolution

Dopecharacterization

Fiberspinning Fiber analysis

42

Standard fiberanalysis

• Titer (linear density)• Tenacity• Elongation at break• Modulus

Polarized lightmicroscope

• Birefringence• orientation

SEM

• Morphology• Structure-

property relations

Mechanical stress

• Fibrillationtendency

IONCELL*/ E-PHK13 wt-%• Textr. = 65-70ºC

NMMO/H2O/E-PHK13 wt-%• Textr. = 100ºC

UNSTRETCHED STRETCHED

Dope preparation

Good spinnability

* Developed by Professor Ilkka Kilpelainen and Dr. Alistair KingAdapted from A. Michud et al. ACS conference, New Orleans, 2013

Rheological characterization

70 75 80 85 90 95 1000

1

2

3

15000

30000

450006000075000 13 wt% Euca-PHK

s-1[

] 0* ,Pa.

s

Temperature, C

atcr

oss-

over

IONCELL

NMMOxH2O

0,01 0,1 1 10 1001E+02

1E+03

1E+04

G''

Dyn

amic

mod

uli,

Pa

Angular frequency, 1/s

G'13 wt% Euca-PHK

1E+02

1E+03

1E+04

Com

plex

visc

osity

,Pas[ ]0*

Dope from novel cellulose solvent shows stablespinning conditions at much lower temperature thandope from NMMO.

°

Total draw ratio

Fiber pick-up

Draw ratio vs Fiber properties

Adapted from A. Michud et al. ACS conference, New Orleans, 2013

0 2 4 6 8 10 12 14 16 18Draw ratio

20

30

40

50

IONCELL13 wt% E-PHK

Tena

city

cond

[cN

/tex]

0 5 10 150,00

0,02

0,04

0,06 n

Draw ratio [ ]

AALTO fiber NMMO fiber (Mortimer, 1996)

Bire

fring

ence

Polymer stability under IONCELLprocess conditions

Very little degradation,which could be furtherreduced by reduceddissolution temperature3 4 5 6 7

0,0

0,5

1,0

dw/d

(logM

M)

log(MM)

PULP DOPE FIBER

kDa PULP DOPE FIBERMw 240.4 216.0 207.5Mn 72.2 76.8 774.6PDI 3.3 2.8 2.8

IONCELL-F Demonstration Run

47

Parameter Unit Fiber tenacities Yarn tenacityCond Wet AALTO Viscose

Titer dtex 1.9±0.2 1.7±0.2Tenacity cN/tex 46.9±3.0 43.5±4.2 34.4±4.7 17.3±1.6Elongation % 10.0±0.8 11.8±1.2 7.4±0.6 18.2±1.2

Brushed fibers 2nd carding

draftingroving

Feeding the roving

Yarn fromRotor spinning

Washed fibers Air-opened

27 runs, 411 g

Production of a Scarf fromIONCELL fibers

VIDEO: IONCELL-F - Cellulosic Fibers from Ionic Liquid Solution,http://www.youtube.com/watch?v=5bhCbGmNfTQ&feature=youtu.be

Outline

Cellulose dissolution andregeneration

Spinning at AALTO

Structure Formation

Regenerated CelluloseProcesses

Background

Composites

Tensile deformation of dry cellulose fibres

Stage I:Internal energy elasticity: Extensionof fibrillar&molecular structure withoutdisrupting H-bonds between fibrils.Plastic deformation due to disruptionof interfibrillar H-bonds close to PL

Stage II:Orientation of fibrils unhindered byinterconnecting H-bonds. Slower build-up of stress

Stage III:Chain slippage and chain rupture

0 5 10 150

200

400

600

800

1000

III

II

Tens

ilest

reng

th,M

Pa

Elongation, %

I

stress-strain curve:IONCELL15 wt% Euca-PHK IONCELL

dry

PL

Stress-strain curves of RegeneratedCellulose Fibers

0 5 10 15 20 250

200

400

600

800

1000

1200

Tena

city

cond

[MP

a]

Elongationcond [%]

CMD CV Cupro

0 5 10 15 20 250

200

400

600

800

1000

1200 CMD IONCELL CV NMMO Cupro BOCELL

0 5 10 15 20 250

200

400

600

800

1000

1200 CMD IONCELL CV NMMO Cupro

0 5 10 15 20 250

200

400

600

800

1000

1200 CMD CV NMMO Cupro

1 +

orientation parameter, , elastic, chain, shear moduli

tensile stress

= 132

1=

1+

Continuous chain modelSerial arrangment of small domains.Elastic tensile deformation is due to the elongation of the polymerchain and the shear deformation of the chain segment.The shear deformation induces a rotation of the direction of the chainsegment towards the fiber axis

Northolt, M.G. et al. Polymer (2001), 42, 8249-8264; Northolt, M.G. Lenzinger Berichte, (1985), 59, 71-79

Fibers > Fibrils > Crystallites-> orientation distribution relativeto fiber axis:

= + 2

For small strains:• elastic extension of the polymer chains• Elastic shearing of the crystallites (row of book

when falling over)

Birefringence vs chain orientation in a fiber: Hermans,Elsevier, 1949

From (1) and (3): nmax is the value for perfectlyoriented fibers for which E = ec

shear between adjacent chains

1 +

=1 +

Linear part:highly oriented fibers

g = 3.7Gpanmax= 0.068

Non-linear part:Medium and low oriented fibers(viscose): g is likely to be afunction of the orientation:

= 1.3 ln 0.81

For E = 10 ->g = 2.2

1Northolt, M.G. et al. Polymer, (2001), 42, 82492Kong, K.; Eichhorn, S.J. Polymer (2005), 46, 6380-6390

0,02 0,03 0,04 0,07 0,140,01

0,03

0,05

0,07

Ioncell, 17 wt% Bocell Fortisan, EHM Viscose

bire

fring

ence

,n

1/E, 10-9m2/N

=+

Birefringence vs Compliance

g = 2.5 GPa, dnmax = 0.0621

g = 3.6 Gpa, dnmax = 0.0812

= 90 ( )

0 5 10 150,00

0,02

0,04

0,06

bire

fring

ence

Draw ratio

IONCELL 13wt% E-PHK IONCELL 17wt% E-PHK NMMO 15wt% HW-PHK*

*Mortimer. Cell Chem Technol, 1996

Structure formation vs mechanical properties

Polymer concentration vs.orientation and tensile strength:higher entanglement leads tohigher orientation, higher elasticityand relaxation time?

For IONCELL, biggest gap in nand from 13 &15 wt% dope conc

Birefringence and tensile stressdevelopment clearly higher forIONCELL as compared to NMMO

0 5 10 15 200

200

400

600

800

1000Te

nsile

stre

ss,M

Pa

Draw ratio

IONCELL 13 wt% E-PHK IONCELL 15 wt% E-PHK IONCELL 17 wt% E-PHK NMMO 15 wt% HW-PHK

0 10 20 30 40200

400

600

800

1000

Tens

ilest

ress

,MP

a

Initial modulus, GPa

IONCELL 15 wt% E-PHK IONCELL 17 wt% E-PHK NMMO 15 wt% HW-PHK

0,01 0,02 0,03 0,04 0,05 0,06

0,0

0,2

0,4

0,61-Tw/Td

birefringence

IONCELL 17 wt% E-PHK NMMO 15 wt% HW-PHK Viscose regular

Structure formation

relates to the extent ofaccessible material within the fiberstructure and thus to thebirefringence.

NMMO and IONCELL seem to have aslightly different structure formation

Bingham, B.E.M. Makromolekulare Chemie (1964), 77, 139-52

IONCELL: Elastic modulus, E, moreaffected by polymer conc than tensilestress.

NMMO: E levels off. Other resultsshow higher Es, but did not show theE values of IONCELL

Rheology of high concentration spinningdopes

According to the Cox-Merz rule,the complex viscsoity, , isequal to steady shear viscosity,when the angular frequency andthe shear rate approach zero.

Cox-Merz rule works well at lowconc., but the differencebetween and startsgetting higher with increasingdope concentration1.

Deviations from Cox-Merz:destruction of strong intra- andintermolecular bonds undershear deformation (shearinduced slippage)?2

0,01 0,1 1 10 1001E+02

1E+03

1E+04

1E+05

= 3.900 Pa.s

13 wt% E-PHK: 70°C oscillatory shear

15 wt% E-PHK: 75°C oscillatory shear steady shear

17 wt% E-PHK: 85°C oscillatory shear steady shear

(com

plex

)vis

cosi

ty,P

a.s

Angular frequency, 1/sShear rate

= 15.500 Pa.s

IONCELLspinning dopes

1Kulicke, W.M.: Porter, R.S. Rheol. Acta (1980), 19 (5), 601-6052Song, H. et al. J. Phys. Chem B (2010), 114, 6006-6013

Outline

Cellulose dissolution andregeneration

Spinning at AALTO

Structure Formation

Regenerated CelluloseProcesses

Background

Composites

Cellulose fibre-reinforced composites

Regenerated Cellulose has unlimited length, precise and predictablegeometry. IONCELL fiber is damage-free, has high strength&toughness.

0 10 20 30 400,0

0,2

0,4

0,6

0,8

1,0

ViscoseModal

Lyocell

Tirecord0

101520 10

,GPa

Young's modulus [GPa]

IONCELL-F

L (wt%)

OL

Fundamental research on structure formation in air-gapand regeneration bath(s).

Fundamental rheological studies of spinning solutions,both shear and elongational.

Next stage of the technical development of theIONCELL process with particular emphasis on thesolvent recovery.

Evaluation of fiber properties within the whole textilechain. Tight collaboration with textile producers.

61

? !Outlook

AALTO University, Biorefineries Research Group

Thank you for your attention!Funding from Finnish Funding Agency for Technology and

Innovation (Tekes) and FiBiC as apart of the Future Biorefineryprogramme is gratefully acknowledged

June, 2013