quality requirements of the dry-wet spinning process...

Third End-Year Meeting of STEP-ITN Marie Curie Initial Training Network

Quality requirements of the dry-wet spinning

process –

analysis of raw materials, solutions and fibers

Frank Wendler, Birgit Kosan, Thomas Schulze, Frank Meister

Centre of Excellence for Polysaccharide Research,

Thuringian Institute for Textile and Plastics Research,

Breitscheidstr. 97, D-07407 Rudolstadt, Germany,

Member of the European Polysaccharide Network of

Excellence (EPNOE), www.epnoe.eu

OutlineOutline

•• Shaping of Cellulose Shaping of Cellulose

•• LyocellLyocell processprocess

•• Aims of analyticsAims of analytics

•• Monitoring analyticsMonitoring analytics

•• ThermostabilityThermostability

From Cellulose to shaped bodies

Non-regular cellulose particlese.g. pulp, short fibres

• Cellulose acetate• Cellulose xanthate• Cellulose carbamate

soluble

C

E

L

L

U

L

O

S

E

• Cellulose silyl ether• mixed cellulose ethers

Shaping through regeneration

of dissolved cellulose

Thermoplasticshaping

fusible

DMAc/LiCl

NMMO • H2OBMIMCl

Spinning set-up for manufacturing of

fibreswater

evaporation

Cellulose additives

solvent

spinning dope

nozzle, ∅∅∅∅ ≈≈≈≈ 70 mm filament take-up

spinning pumps

washing

dope storage tank

air gap spinning capillaries

regenerated cellulose filaments

dope preparation

filament

solventrecovery

spinning

Raw materials

Pilotscale plant of Smart Fiber AG, Rudolstadt –Filament after-treatment, drying and winding.

• Process limits : Dope throughput

Take-up velocity

Dope viscosity → Deformation force

Solvent exchange rate

• Process limits : Dope throughput

Take-up velocity

Dope viscosity → Deformation force

Solvent exchange rate

Restricted processing window

Analytical methods

PurityParticle size, pH, surface

Special properties

PolymersSolvent

StabilizersAdditives

Raw materials

Solution stateSpinning behaviour

Thermostability

PulpSuspension

SolutionMelt, Gel

Solutions

PerformanceSpecial features

Fibers, Nano-fibersFilmsBeads

Non-wovens

Shaped bodies

Media

Analytical methods

X-ray (crystallinity)H2O content-CO, -COOH

BioactivityAminespH

...... ...

Adsorption capacityMetalsAmines

Water retention behaviorpHPorosity

White degreeThermostabilityParticle size

Recovery of additiveChromophores (UV/VIS)DP, molar mass

Solvent / metals residuesRheologyH2O content

PorosityDP, molar massα-Cellulose

Surface (Elmi, AFM, ZETA-pot.)MicroscopyMetals

Textil-physical propertiesParticle sizeAsh

FibersSolutionsRaw materials

Raw materials

Solution Fiber

Cellulose – Requirements profile

325 – 395 ml/gViscosity (Cuen)

< 0,5%Ash

> 90%White degree

< 35 µmol/gCO groups

< 25 µmol/gCOOH groups

< 0,5%Soluble content in 20% NMMO

< 100 ppmSum of alkali/earth alkali metals

< 10 ppmSum of heavy metals

(Fe, Cu, Ni, Cr, Mn, Co)

> 90%α-cellulose

480 – 580DP (Cuoxam)

Cellulose –Requirements profile

Not to forget:

Origin – cotton, wood

Processing – sulfite, sulfate

Refining - bleaching

Krässig et al. 2007 Cellulose. In Ullmann`s Encyclopedia of Ind. Chem. Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

α-Cellulose content of various paper and dissolving pulp

0

0,05

0,1

0,15

0,2

0,25

0,3

0,0010,010,1110100

Radius [µm]

Cu

mu

lati

ve

in

tru

sio

n [

ml/g

]

Blücher Precolith Ambersorb

Precolith ungem. Kuhera BR255

Hg porosimetry of different charcoals

Extraordinary effect on adsorption capacity

but enhanced thermal

degradation !

Wendler F., Kolbe A., Meister F., Heinze T. 2005. Macromol. Mat. Eng. 290: 826-832.

200 nm

MicroSilver BG™- porös, 80 – 140 nm

NanoSilver BG™- kolloidal, 5 – 20 nm

Wendler F., Meister F., Montigny R., Wagener M. 2007. FIBRES & TEXTILES in Eastern Europe 15, No. 5-6 (64 - 65): 41-45.

Extraordinary effect on fiber bioactivity

but enhanced thermal

degradation !

Raw materials

Solution Fiber

Surface topography on 1 x 1 µm sample size for a cellulose/xanthan fiber from EMIMac (Ra = roughness)

NMMORa 4.8 nm

NaOHRa 20.6 nm

EMIMacRa 0.93 nm

Prof. Dr. Stana-Kleinschek, University of Maribor

Atomic force measurement (AFM)

0

50

100

150

200

250

300

350

400

0 10 20 30 40 50 60 70 80 90

CHI [°]

Inte

nsität

[cps

]

Total scan with χχχχ sectionsthrough the reflexes at 2θθθθ

0

50

100

150

200

250

300

350

400

30 50 70 90 110 130

Chi [°]

Inte

nsität

[cps]

0

200

400

600

800

1000

1200

1400

1600

1800

0 10 20 30 40 50 60 70 80 90

CHI [°]

Inte

nsität

[cps]

Dr. Thomas Schulze, TITK

Raw materials

Solution Fiber

cell. xanthate/NaOH cellulose acetate/ cellulose/Cuoxam cellulose/ cellulose/

acetone NMMO/H2O BMIMCl

aqueous acids solvent evaporation aqueous acids water water(water)

irregular irregular/fibrous fibrous fibrous fibrous

Target: Dissolution of cellulose

→ Interaction of polymer and solvent is of fundamental importance for

understanding and perception of proceeding processes in polymer dissolution

→ structure of regenerates, structural changes of polymer and solvent, dope

properties and shaping behaviour should be discussed

→ different fibrous structures of regenerated films regarding to precipitating

structures

Michels, C., Kosan, B. 2005. Lenzinger Berichte 84, 62

Herlinger, H., Grynaeus P., Hirt P. et al. 1990. Lenz. Ber. 69, 65.Cibik T. 2003. Investigation of the system NMMO/H2O/Cellulose. Thesis, TU Berlin. Michels C., Kosan B. 2005. Lenz. Ber. 84, 62.

→ high ordered dissolved state is detectable in viscous NMMO melts containing different amounts of water

→ connected to the distinctive H-bond system existing in solid state

→ at about 62 % NMMO a stable 2,5 hydrate is formed

→ NMMO forms a second stable hydrate, NMMO monohydrate

→ high ordered state won’t be significant changed by the addition of polymers like cellulose but slightly disturbed

→ NMMO monohydrate dissolves cellulose fast macroscopic

- 1,5 n H2O

t = 0 minFibers dispersed in 60 % NMMO

t = 60 minAfter adjustment 80 % NMMO

t = 90 minAfter adjustment 80 % NMMO

t = 120 minAfter adjustment 80 % NMMO

0

20

40

60

80

100

0,1 1 10 100

Particle diameter [µm]

Su

m d

istr

ibu

tio

n [

%]

0

80

160

240

320

400

Den

sit

y d

istr

ibu

tio

n

Cellulose concentration 12,3 %Eucalyptus, DP 563 Zero shear viscosity 9910 PasParticle volume 1,3 µl/l solution Max. Particle diameter 18 µmColour number 12Filter amount 31

Particle analysis: Sum and density distribution of a cellulose/NMMO solution

5

10

15

20

25

0,5 0,7 0,9 1,1 1,3 1,5 1,7 1,9 2,1 2,3 2,5

Fineness [dtex]

Ma

x. p

art

icle

siz

e [

µm

]

Particle size criterion:

< 40 µm fiber< 20 µm filament

25

1. Determination of the zero shear viscosity

rotation mode with controlled shear stress (90 Pa)

2. Characterisation of the flow behaviour

oscillation mode (frequency sweeps between 0.046 and 14.7 Hz) at different temperatures for the calculation of master curves (storage and loss moduli as well as the complex viscosity depending on frequency respectively angular rate, referring to a reference temperature, i.e. 85°C)

determination of the cross over between storage and loss modulus and the plateau moduli (plateau value of the storage modulus)

calculation of the weighted relaxation spectra (relaxation

time λm, information on the molecular mass distribution of the polymers which are involved in the solution stateby rheological methods)

Rheometry of cellulose dopes is targeted to …

© maaja Design

© maaja Design

© maaja Design

Microscopic images by polarisation light of cellulose solutions in NMMO (16,5%) and EMIMAc (24,9%)

Kosan B., Schwikal K., Meister F. 2010. Cellulose 17: 495–506

2,5

2,7

2,9

3,1

3,3

3,5

3,7

3,9

4,1

4,3

4,5

0,0025 0,0026 0,0027 0,0028 0,0029 0,003

1/T [1/K]

lg n

[P

a s

]81°C

76°C

Viscosity measurement of cellulose/EMIMAc solutions at differenttemperatures at a shearing rate of 0.5 s-1 (Arrhenius plot)

28,0%

24,9%

19,2%

Main actions and degradation reactions in the system cellulose/NMMO

NMMOlabilityoxident

Celluloseendgroupssugar acidsradicals

Hydrogen bond systembetween cellulose and NMMO

Conta-

minationsIronCopper O

OH

OH

HOCell-O

O-Cell

ON

O

O

OH

OH

HOCell-O

O-Cell

Properties of additives

pH value -COOH, -NH2

structurepore sizeparticle size porosity

Temperature+

Pressure

O

OH

OH

HO

OH

O

OH NO

O

Cell-O

+

NO

OHOCell-

HO

OH

OH

Thermal degradation

Oxidation of cellulose, deoxygenation of NMMO

Radical reaction

Polonovski type reaction

NO

OAA

NO

O-Acyl

NOB

CH2 + O-Acyl H-B+

OH-

NO CH2OH

NO H

+ HCHO

AA = acylating agent

B = Base

NO

O

Fe(II)+ +.

Fe(III)NO2 H+

- H2O

O

NO HNO H2O+

_

+NO 1/3 1/3 1/32/3 + + CO2

Lukanoff, B., Philip, B., Schleicher, H. 1984. Acta Polymerica 35, 339-343.

Taeger, E., Franz, H., Mertel, H. 1985. Formeln, Fasern, Fertigware 4, 14-22.

Buijtenhuijs, F.A., Abbas, M., Witteveen, A.J. 1986. Papier 12, 615-619.

Rosenau, T., Potthast, A., Sixta, H., Kosma, P. 2001. Prog. Polym. Sci. 26, 1763-1837.

Wendler F., Graneß G., Heinze T. 2005. Cellulose 12/4: 411-422.

40 °C, 1min

0,8×2,0 magnification with microskope SMC 4, Fa. Ascania, heating table Linkam.

104°C, 5 min

112°C, 15 min

116 °C, 20 min

119 °C, 22 min

123 °C, 26 min

126 °C, 28 min

129 °C, 31 min

131 °C, 34 min

138 °C, 41 min

141 °C, 44 min

145 °C, 48 min

147 °C, 50 min

149 °C, 52 min

149 °C, 53 min

150 °C, 54 min

150 °C, 54 min

150 °C, 54 min

150 °C, 55 min

150 °C, 60 min

150 °C, 70 min

150 °C, 75 min

150 °C, 75 min

150 °C, 80 min

150 °C, 90 min

Accidere ex una scintilla incendia passimTitus Lucretius Carus (96 – 55 v. Chr.)

'Big fires often arise from a little spark'

Problem of industrial reactors:

Heat development ~ Volume ~ r3Vessel

Heat release ~ Area ~ r2Vessel

Vessel volume Cooling time for 1 K

Cooling speed K/min

10 ml 11 s 5,5

100 ml 20 s 3

1000 ml 2 min 0,5

2,5 m3 21 min 0,047

25 m3 233 min 0,0043

Phi = (ms * cs + mg * cg) / (ms * cs),

-50

-40

-30

-20

-10

0

10

20

25 45 65 85 105 125 145 165 185 205 225 245

Temperature [°C]

En

thal

py

[mW

]

5%Cell., BMIMCl

5%Cell., NMMO

NMMO

DSC measurements of NMMO and cellulose solutions in NMMO and BMIMCl

Fast screening method, 5 - 20 mg sample massOnset-Temperature, reaction enthalpy

0

50

100

150

200

250

300

0 50 100 150 200 250 300 350 400

Time [min]

Te

mp

era

ture

[°C

]

0

5

10

15

20

25

30

35

40

45

Pre

ss

ure

[b

ar]

p

-0,5

0

0,5

1

1,5

2

2,5

30 60 90 120 150 180 210 240

Temperatur [°C]

dp

/dt

[ba

r/m

in]

-0,5

0

0,5

1

1,5

2

2,5

dT

/dt

[K/m

in]

dp/dt

dT/dt

-0,05

0

0,05

0,1

0,15

0,2

100 120 140 160 180 200

Temperatur [°C]

dp

/dt

[bar/

min

]

-0,05

0

0,05

0,1

0,15

0,2

dT

/dt

[K/m

in]

Ton = 160°C

Dynamic measurements by means of the mini-autoclave:Sample mass 2 g, 0,75 K/min, 30 – 300°CTemperature and pressure !

Onset temperature (Ton): First thermal activity

Mini - autoclaveRADEX - Reaction calorimeterRapid Detector for Exothermic ProcessesFa. Systag/CH

Calorimetric measurements

131

142

146

151

160

145

163

120 130 140 150 160 170

9% Cellulose/NMMO modified w ith reactive activated

charcoal

11% Cellulose/NMMO + 50 ppm Fe(II)

11% Cellulose/NMMO + 50 ppm Fe(III)

9% Cellulose/NMMO modified w ith acidic ion exchange

resin

11% Cellulose/NMMO + NaOH, propyl gallate

11% Cellulose/NMMO

NMMO monohydrate

Onset - Temperature [°C]

Calorimetric measurements - mini-autoclave

Comparison of onset - temperatures

-0,2

-0,1

0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0 10 20 30 40 50 60 70 80 90

Time [h]

Pre

ssu

re [

bar]

10% cellulose + 5% charcoal in NMMO

10% cellulose + 2% ZnO in NMMO

11% Cellulose in NMMO

10% cellulose + 5% charcoal in BMIMCl

Calorimetric measurements: SEDEX oven, Fa. Systag/CH

Adiabatic calorimetry: Changes in isoperibolic pressure of cellulosesolutions at 110°C over 96 h.DEWAR vessel with 300 g sample mass

-100

0

100

200

300

400

500

600

0 5 10 15 20 25 30

Time [min]

Ab

so

rpti

on

[m

AU

]

Distillate of cellulose/NMMO solution

High Performance Liquid Chromatography (HPLC)

N

O

H

N

O

OH

N

OH

NN

OH

CHO

N

O

Wendler F., Kolbe A., Meister F., Heinze T. 2005. Macromol. Mat. Eng. 290: 826-832.

High Performance Liquid Chromatography (HPLC)

Comparison of onset temperature (Ton) and concentration of N-methylmorpholine

(NMM) in destillates of Lyocell solutions modified with activated charcoal.

0

2000

4000

6000

8000

10000

12000

0,9 1,8 2,7 3,6 4,5 6,8 8,6

Concentration [%]

NM

M [

mg

/l]

120

125

130

135

140

145

150

T o

n [

°C]O

N

CH3

Ton

Todi L.-N., Wendler F., Meister F., Heinze T. 2011. Analytical investigation of various cellulose-ionic liquid systems. 2nd

EPNOE Conference – Polysaccharides as source of advanced and sustainable products, Wageningen, NL

Qualitative determination of the volatile compounds in the Cellulose/EMIMAc system (Head-space-GC/MS)

Electron Spin Resonance Spectroscopy

H50 G

R2

*CH

3

R3 H

*CO

R2

R2

R2R

2R3

R3

Experimental ESR spectra of NMMO/cellulose solution recorded after 16 min excimer laser (� = 248 nm) photolysis at 77 K.

Konkin A., Wendler F., Roth H.-K., Schrödner M., Meister F., Heinze T., Aganov A., Garipov R. 2006. Magn. Reson. Chem. 44/6: 594-605.

mN

I= 0

mN

I= - 1

- NO*

-

ACH2 A

CH3

H 50 G

2A2

(N)

experiment

simulation

- CH2- NO

*- CH

3

mN

I =1

2AN

1

105 K

Experimental ESR spectra recorded after 16 min irradiation at 105 K and their simulations Constructed spectra of pure -NO٠ radical and R_NO٠-R'

.CH2 CH2 N CH3CH2OCH2

.O

CH3

O.

CH2 CH3N+

CHOCH3.

CH2 CH OH

CCH3

O

H

.

H+

O

NO

Suggested pathway

Electron Spin Resonance Spectroscopy

Changes in UV/VIS spectrum of cellulose/NMMO solutions heated at 120°C

After 400 min

Immediately after preparation

∆ E

Observation wave length

UV/VIS spectrometry

Heating coil

Sample

Copper block

Aperture slitQuarz window

Varistors

34,0

24,5

18,5 I0

Distance ring: 0,35 mm

Wendler F., Graneß G., Heinze T. 2005. Cellulose 12, 411-422

Design of the cuvette for heating

of cellulose

solutions

140°C

130°C120°C

110°C

100°C

Extinction-time curves of a cellulose/NMMO solution at different

temperatures. Determined at λλλλ 400 nm.

Extinction

Time [min]

UV/VIS spectrometry

90°C

100°C

110°C

120°C

130°C

140°C

Extinction-time curves of a cellulose/NMMO solution modified with an acidic ion

exchange resin at different temperatures. Determined at λλλλ 400 nm.

Extinction

Time [min]

UV/VIS spectrometry

Exothermicity: temperature development exclusively caused by the exothermic reaction accompanied by pressure rise.⇒ sporadically, uncontrollablly, autocatalytically running reactions

Determination by calorimetric and spectroscopic methods:Pressure and temperature rise are overlayed by the pyrolyse

Three steps:segregation oscillation degradation

Low thermal conductivity Compensation by convection

0

0,5

1

1,5

2

2,5

3

3,5

0 50 100 150 200 250 300 350 400

Time [min]

Ab

so

rba

nc

e

12% cellulose in EMIMac, recycled

12% cellulose in EMIMac, new

UV/VIS spectrometry

Extinction-time curves of a cellulose/EMIMAc solution at 120°C, λλλλ 400 nm.

T [

°C]

0

20

40

60

80

100

120

140

0 100 200 300 400t [min]

p [

mb

ar]

0

20

40

60

80

100

120

140

p T

Wendler F., Graneß G., Project reports 2008/2010Wendler F., Graneß G., Büttner R. 2005. DE 102005 010560 B4, 04.03.2005.

Special designed calorimetric cell.

Changes in isoperibolic pressure of 11% cellulose solution in NMMO at 130°C over 400 min, 3 - 4 g sample mass

Adiabatic calorimetry: Changes in isoperibolic pressure of 11% cellulosesolution in NMMO at 110°C over 96 h.DEWAR vessel with 300 g sample mass

0

20

40

60

80

100

120

0 25 50 75

Time [h]

Te

mp

era

ture

[°C

]

0

0,05

0,1

0,15

Pre

ss

ure

[b

ar]

0

50

100

150

200

250

300

350

400

0 2 4 6 8 10 12 14 16

Time [h]

Te

mp

era

ture

[°C

]

0

0,5

1

1,5

2

2,5

Pre

ss

ure

[b

ar]

Sample temperature

Oven temperature

Pressure

Adiabatic calorimetry: Changes in isoperibolic pressure of 11% cellulosesolution in NMMO at 130°C over 96 h.DEWAR vessel with 300 g sample mass

0

0,2

0,4

0,6

0,8

1

1,2

1,4

0 2 4 6 8 10 12 14

Time [h]

dT

/dt

[K/m

in]

0

0,01

0,02

0,03

0,04

0,05

dp

/dt

[bar/

min

]

dT/dt

dp/dt

Adiabatic calorimetry: Changes in isoperibolic pressure of 11% cellulosesolution in NMMO at 130°C over 96 h.DEWAR vessel with 300 g sample mass

Target:

Dissolution of cellulose

and

to keep the cellulose in solution

under practical conditions:

Time

Temperature

1 mm 1 2 3 4

Reasons for dissolution / segregations:

• Solution stateNetworks, gelic behaviorSchurz J. 1979. Papier 12: 558-561

• MorphologyCrystalline/amorphous regions, surface properties, porosityKlemm D., Philipp B., Heinze T., Heinze U., Wagenknecht W. 1998. Comprehensive Cellulose

Chemistry. Wiley, Weinheim.

• Ionic interactionsHydogen-bond network (NMMO), complexations(LiCl/DMAc, Cuoxam, Cuen, FeTNa)Bechtold T., Manian A.P., Oeztürk H.B. et al. 2011. 2nd EPNOE conference, Wageningen, NL

• Amphiphilic character of celluloseLindman B., Karlström G., Stigsson L. 2010. J. Mol. Liquids 156: 76-81.

Bergenstråhle M., Brady J. W. et al. 2010. Carbohydr. Res. 345: 2060-2066.

... more practical reasons:

• Time

Dwell time in reactor, tubes

• Temperature

• Water content

• Cellulose concentration

• Type of cellulose

DP, MWD

• Solvent

Co-solvent, purity

• Stabilizers

• Functional additives

SAP, char coal, carbon black, ceramics, Ag NPWendler F., Graneß G., Büttner R., Meister F., Heinze T. 2006. J. Polym. Sci. Part B: Polymer Physics,44/12: 1702-1713.

Spinning stabilitySpinning stability

Conclusions

Monitoring of Lyocell solutions ensures

Conclusions

Monitoring of Lyocell solutions ensures

Requested fiber performanceRequested fiber performance

RecyclabilityRecyclability

Thermal stabilityThermal stability

Choice of appropriate raw materialsChoice of appropriate raw materials

Process efficiencyProcess efficiency

Acknowledgements: Financial support was granted by the EC 6th framework program, contract number NMP3-CT-2005-500375 (project acronym: Polysaccharides), the EC 7th framework program, Marie Curie Initial Training Networks (ITN), call: FP7-PEOPLE-2007-1-1ITN, contract number 214015 (project acronym: STEP) and the German Ministry of Economics and Technology (INNO-WATT IW091005). Furthermore the authors thank all who were involved in the works and have contributed to the realization of the results.

Thank you very much for your attention!

Special thanks to:

Birgit Kosan

Marcus Krieg

Michael Mooz

Thomas Schulze

Frank Meister