COST Action FP 1205 Cellulose material properties and industrial

potential

Final Meeting in StockholmMarch 8th, 2017

Herbert Sixta

Are Ionic Liquids suitable for the Lyocell Spinning Process?

No info on regeneration conditions, filmsor fibre mechanical properties

The first paper reporting about theproduction and characterization of IL-based Lyocell fibers

PART 1

ILs as Cellulose Solvents• Cellulose Dissolution• Rheology• Thermal Stability• Toxicity

Ionic liquids(M.P. < 100°)

R.T. ILs(M.P. < RT)

Acid superbaseconjugates

(M.P. > RT)

Phase-SeparableILs

Aqueous OniumElectrolytes

R1 R2 R3

H

1,5-diazabicyclo[4.3.0]non-5-ene (DBN)

1,8-diazabicyclo[5.4.0]undec-7-ene (DBU)

7-methyl-1,5,7-triazabicyclo [4.4.0] dec-5-ene (MTBD)

N,N,N,N,NN,-hexamethylphosphorimide triamide (HMPI)

1,2-dimethyl-1,1,4,5,6-tetrahydropyrimidine (DMP)

N,N,N,N,-tetramethylguanidinium (TMG)N N

NH

N N

O

O-

Parviainen, A.; King, A.W.T., Mutikainen, I.; Hummel, M.; Selg, C.; Hauru, L.K.J., Sixta, H.; Kilpelainen, I. ChemSusChem 2013, 6, 2161-2169Lenz. Ber (2005), 84:71-85Lenz. Ber (2006), 86:154-161

Cellulose Dissolving ILs

Chem. Lett. 2012, 41, 987-989; ChemSusChem 2012, 5, 388-391

Amino Acid Ionic Liquid

Dissolution of cellulose (MCC)at 100°C, 10 min:

[N221ME][Ala], KT-β = 1.041 12 wt%[N221ME][Lys], 11 wt%[N221ME][OAc], 7 wt%

[N221ME][Ala]: DMSO = 1:1 (w/w), χIL = 0.25dissolves 22 wt% cellulose at RT!!

Amino group essential to realize high cellulose dissolution->amino group mayinteract with certain parts of cellulose.

N+

ONH2

O

-O

[N221ME][Ala]

N,N,-diethyl-N-(2-methoxyethyl)-N-methyl-ammonium alanine

Dissolution Window

Hauru, L.K.J.et al.. Biomacromolecules 2012, 13, 2896-2905.

KT: Net-basicity Concept

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 NMMOH2O NMMO2H2O LiCl/DMAc

[Pnnnn] [Rmim]MeOHPO2

[eimH]EtCOO DMAPH]EtCOO [HOC2mim] [EMIM] [BMIM]

[DBNH][OAc]

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)

Rheological properties

70 75 80 85 90 95 1000

1

2

3

15k

30k

45k60k75k

20 wt%

13 wt%

[emim][OAc]

Euca-PHKs

-1

[] 0* , P

a.s

Temperature, C

at c

ross

-ove

r

[DBNH][OAc]NMMOxH2O

13 wt%

Cellulose solutions (dopes)

Thermal stability of ILs

Partly unpublished results

50 100 150 200 250 3000

2550

70

80

90

100W

eigh

t per

cent

Temperature, °C

[BMIM][dmp] [AMIM][dmp] [EMIM][OAc] [DBNH][OAc] [TMGH][OAc]

PART 2

Cellulose Coagulation• Diffusion of water• Structure formation• Cellulose gelation

Diffusion of water into the filament

Hauru, L. et al. Soft Matter, 2016, 12, 1487-1495

0 2 4 6 8 10 12 140,6

0,4

0,2

0,0

radial distance from center [µm]de

pth

trave

lled

in b

ath

[m]

0,01

0,05

0,10

0,15

0,20

0,40

0,80

1,00NMMO

20 s40 s60 s90 s

120 s150 s180 s

Water diffusion• fastest for NMMO• slowest for

[emim]OAc

0 2 4 6 8 10 12 140,6

0,4

0,2

0,0

radial distance from center [µm]de

pth

trave

lled

in b

ath

[m]

0,01

0,05

0,10

0,15

0,20

0,40

0,80

1,00[DBNH][OAc]

0 2 4 6 8 10 12 140,6

0,4

0,2

0,0

radial distance from center [µm]de

pth

trave

lled

in b

ath

[m] 0,00

0,05

0,10

0,15

0,20

0,40

0,80

1,00[emim][OAc]

0 5 10 15 20

0,2

0,4

0,6

0,8

1,0

Pene

trat

ion

dept

h (m

)

Extrusion velocity (m/min)

∆· ··

Regeneration depth, ∆ , of a [DBNH][OAc] dope

, 100

1.55 · 10 ⁄

Ve = 0.05 mL/minDR = 10V0 = 63.7 m/min

Rh (LS)

5 wt% 8 wt%

0 5 10 15 200

10

20

30

40

50

60

Tena

city

(cN

/tex)

con

d

Draw ratio

0 wt% water 2 wt% water 5 wt% water

0,1 1 10 1000

200

400

600

800

Rh,

nm

Water content, %

[emim][OAc]

Olga Kuzmina et al. Fibers and Textiles in Eastern Europe 2010, 18, 3 (80), 32-37

13 wt% birch-PHK in[DBNH][OAc]

Anne Michud, Doctoral Dissertation, Aalto University, Finland, p38

Regeneration in water

0 10 20 30 40 50

0

100

200

300Tu

rbid

ity (N

TU)

water (%)

Turbidity

0,1

1

10

100

0 10 20 30 40 50

0

100

200

300Tu

rbid

ity (N

TU)

water (%)

Turbidity

0,1

1

10

100

Complex viscosity

Com

plex

vis

cosi

ty [P

a·s]

0 10 20 30 40 50

0

100

200

300Tu

rbid

ity (N

TU)

water (%)

Turbidity

0,1

1

10

100

tan

Complex viscosity tan

Com

plex

vis

cosi

ty [P

a·s]

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

M. Hummel, ACS conference, San Diego 2012Le Kim Anh, R. Sescousse, T. Budtova. Cellulose 2012

PART 3

Spinnability• Causes for instability• Effect of MMD

SpinnabilitySpinning solvent

D0[m]

Textr[°C]

DRmax Tenacity[cN tex-1]

[DBNH][OAc] 100 70 7,5 38.5±8.4

NMMO.H2O 100 95 6,2 31.2±6.6[TMGH][OAc] 100 80 2,0 10.9±1.1[emim][OAc] 250 90 2,9 13,9±1.6

[TMGH][OAc] and [emim][OAc] not spinnable.

Spinning solvent

D0[m]

Textr[°C]

DRmax Tenacity[cN tex-1]

[DBNH][OAc] 100 70 7,5 38.5±8.4

NMMO.H2O 100 95 6,2 31.2±6.6[TMGH][OAc] 100 80 2,0 10.9±1.1[emim][OAc] 250 90 2,9 13,9±1.6

Spinning performance

0 20 40 60 80 1000

20

40

60

80

100

D [1

0-11 m

2 /s]

water content [%]

[DBNH]OAc [emim]OAc [TMGH]OAc NMMO

Poorly orientable network of [TMGH][OAc] and [emim][OAc] dopes.Constant diffusion across water contentindicative for gelatineous network.

Solvent diffusion vs. water cont1 2 3 4 5 6 7 8

0

10

20

30

40

50

[emim]OAc [DBNH]OAc [TMGH]OAc NMMO

bire

fring

ence

DR

103

[emim][OAc] fibers: orientation develops poorly due to lowresilience in the core.

[TMGH][OAc] fibers: solidified gel->solution behaves as a permanent network.

Fiber orientation vs. DR

L. K. J. Hauru, M. Hummel, K. Nieminen, A. Michud and H. Sixta. Soft Matter, 2016, 12, 1487--1495

L. K. J. Hauru, M. Hummel, K. Nieminen, A. Michud and H. Sixta. Soft Matter, 2016, 12, 1487--1495

Yield strain and stress decrease at 0.5 nH2O/nIL obviouslydue to a low water diffusion.Telescopic-type breach because of very low resilience in the core during the onset of regeneration.

Incipient [emim][OAc] filament

Michud et al. Polymer 75 (2015), 1-9

0 5 10 1510

20

30

40

50

60

Tena

city

(cN

/tex)

Draw ratio

Blend 1 - 15% Blend 2 - 15% Blend 4 - 13% Blend 5 - 15% Blend 6 - 13% Blend 6 - 15%

Molecular Weight of the Solute

0 1 2 3

2x103

4x103

6x103

8x103

G',

G'' a

t CO

P (P

a)

Angular frequency of COP (s-1)

Blend 1 - 15% Blend 2 - 15% Blend 3 - 15% / Blend 4 - 13/15% Blend 5 - 15% / Blend 6 - 13/15% / Euca. - 13/15%

103 104 105 106 107

Molar Mass (Da)

Blend 2PDI 5.9

6.9 23.9

103 104 105 106 107

Molar Mass (Da)

Blend 1PDI 5.3

6.8 12.5

103 104 105 106 107

Molar Mass (Da)

Blend 3PDI 2.1

1.0 19.6

103 104 105 106 107

Molar Mass (Da)

Blend 6PDI 3.4

3.5 22.5

PART 4

Fiber properties• First generation ILs• Acid-superbase conjugates• Structure-property relationship

IL-spinning in literature

[amim

]Cl

[bmim]C

l[em

im]O

Ac[bmim

]OAc

[emim

]dep0

20

40

60

Tena

city

cond

(cN

/tex)

Lenz. Ber (2005), 84:71-85Lenz. Ber (2006), 86:154-161Lenz. Ber (2006), 86:144-153Cellulose (2005), 85:59-66Macromol Mater Eng (2010), 295:676-681Polym Eng Sci (2012), 52:1708-1714

J Appl Polym Sci (2010), 115:1047-1053J Appl Polym Sci (2013), 128:4141-4150Cellulose (2012), 19:1075-1083Patent DE102012005489A1ACS Sustainable Chem&Eng (2016), 4:4545-4553Patent WO2013/144082A2

• Reaction of imidazolium cationwith the REG

• Formation of carboxylic acids, HCOOH, as a result of pulpdegradation

Ebner, G. et al. Tetrahedron Letters (2008), 49(51), 7322)

• High temperature > 100°C

• Poor spinnability

• Corrosion

• Excessive DP degradation

Successfully spun fibers fromAcid-Superbase Conjugates cellulose solutions

0 5 10 1520

30

40

50

60

Tena

city

(cN

/tex)

Draw ratio

13 wt% [DBNH][OAc] 13 wt% NMMO

Birch PHK

3 4 5 6 70,0

0,2

0,4

0,6

0,8

Diff

eren

tial M

ass

Frac

tion

Log Molar Mass

Birch PHK (312/69) NMMO (298/70) [DBNH][OAc] (328/76)

Substrates Cell%

Titerdtex

TenacitycN/tex

Elong%

NMMO-fibre 13 1.53 54.3 11.2

[DBNH][OAc] fibre 13 1.55 58.5 11.0

Unpublished results

Opportunities: Strong fibers with uniform nanostructure

30% Lignin, DR=10.6Ftot = 0.456

Pure cellulose, DR=10.6Ftot = 0.685

Asaadi, S.; Nishiyama, Y.; Sixta, H. unpublished results Hailwood, A.J. and S. Horrobin, Trans. Faraday Soc., 1946. 42B: p. 84-92, discussion 94-102

0 5 10 15 20 250

200

400

600

800

1000

CuproViscose, CV

NMMO

Tena

city

cond

[MP

a]

Elongationcond [%]

IONCELL

Modal, CMD

0 5 10 150,4

0,5

0,6

0,7

0,8

0,9

1,0f(c), f(a)

Draw ratio [ ]

f(c)

f(a)

Sixta, H. et al. NPPRJ, 30(1), 2015, 43-57

PART 5

Solvent Recycling• Removal of Water• Challenge of limited ionicity of

protic acidic ionic liquids

Premixing Dissolution SpinningFiltration

Washing, cutting, pre-conditioning,

drying

Pulp

Staplefibers

Evaporation

Water

Water

Water

c(IL) < 20 wt%

EvaporationPurification

Purification

IL preparationImpurities

MakeupIionic liquid

Water

A C

Water

Water

c(IL) < 20 wt%

Challenge: Solvent recycling

Thin film evaporator (RF10, UIC GmbH)

Ostonen, A. (2017). Doctoral Thesis, Aalto 9/2017.Hauru, L.. Et al. (2016). Soft Matter, 12, 1487-1495Pariainen, A. et al. ChemSusChem, 2013, 6, 2161-2169

Strong interaction between IL& water‒ Tolerable water content < 8 wt%‒ Achieved water content < 3 wt%

Removal of water

Acc. Chem. Res. 2007, 40(11), 1228-1236JACS (2003), 125-15411-15419

Hydrolytic instability of of DBN

• Vaporized DBN hydrolyses very fast to APP• in the condensate APPAc formed only at drastic conditions. • DBN regeneration by acid catalysis (reversion)

23

PART 6

Conclusions

• Acid-superbase conjugate ionic liquids currentlythe only promising class of ILs capable for theproduction of strong man-made cellulose fibres.

• However, solvent recovery challenging due to losses of small neutral base fractions.

• Opportunities exist to achieve the requested almostquantitative solvent recycling rate.

Acknowledgement