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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