1

Les futures fibres

cellulosiques artificielles.

Procédés écologiques

pour générer des fibres

de demain

Patrick Navard Centre de Mise en Forme des Matériaux (CEMEF)

Ecole des Mines de Paris-CNRS

France

version 0.4

2

Biomass-based polymer

activities in CEMEF

Basic and applied research

20 active projects with industry

Industrial Chair “Bioplastiques” 2009 –

2013

Durable bioplastics

EPNOE:

European

Polysaccharide Network of

Excellence

0

0.2

0.4

0.6

0.8

1

1.2

1.4

3.0 4.0 5.0 6.0 7.0log Molar Mass

Dif

fere

nti

al

We

igh

t F

rac

tio

n

SE DP 360 original wood pulp,

SE DP 360 fraction 1,

SE DP 360 fraction 2,

SE DP 360 fraction 3,

SE DP 360 fraction 4 ,

Soluble

fraction

(4)Insoluble

fractions

(1, 2, 3)

0

0.2

0.4

0.6

0.8

1

1.2

1.4

3.0 4.0 5.0 6.0 7.0log Molar Mass

Dif

fere

nti

al

We

igh

t F

rac

tio

n

SE DP 360 original wood pulp,

SE DP 360 fraction 1,

SE DP 360 fraction 2,

SE DP 360 fraction 3,

SE DP 360 fraction 4 ,

Soluble

fraction

(4)Insoluble

fractions

(1, 2, 3)

3

Content

A: Introduction: cellulose fibres

B: Present fibres: properties and difficulties

C: Fibres coming from new solvents

D: Conclusions

4

A: Introduction: cellulose fibres

B: Present fibres: properties and difficulties

C: Fibres coming from new solvents

D: Conclusions

5

algae

sea animals (tunicin) cotton

trees

bacteria fungi

Cellulose sources

6

Cellulose is the most abundant natural polymer on Earth.

Cellulose cannot be melted.

Cellulose must be either solubilized or derivetized.

Cellulose is a « normal » polymer.

7

Organisation of a natural fiber

- fiber diameter: 10-30 microns

- a very complex “composite”:

cellulose, lignin, hemicellulose,

proteins

- the composition varies a lot!

almost pure cellulose 50-95% cellulose

8

A: Introduction: cellulose fibres

B: Present fibres: properties and

difficulties

C: Fibres coming from new solvents

D: Conclusions

9

0

10

20

30

40

50

60

1950

1960

1970

1980

1990

2000

2010

cellulosics

Synthetics

Cotton

wool

Mean fibre consumption

per kg per person

*Source: Lenzing AG

Examples of fibres

constant increase (2 à 3% per

year)

cotton culture is not increasing

sustainability issues

10

Why to use cellulose fibres ?

Confort in wet environment, softness

This is due to the special properties of cellulose

towards water: very hydrophylic, but not soluble

Existence of many h-bonds around cellulose

molecules water affinity

Hydrophobic moieties no dissolution in

water

Swelling of fibers in water associated with an

increase of mechanical resistance

11

20-60s

0 s

Swelling of a

regenerated cellulose

fibre

Swelling of cotton

fibre

12

Two main choices

Cotton

Cultivated in fields

Cotton hairs are nearly pure cellulose

Viscose

Based on cellulose extracted from wood or other plants

Spun from a cellulose derivative solution

13

Cotton fibres

World production : 25 million tonnes annually,

accounting for 2.5% of the world's arable land.

Pesticides: about 25% of pesticides used in the World.

Water use: 2.6 per cent of the global water use. As a

global average, 44 per cent of the water use for cotton

growth and processing is not for serving the domestic

market but for export. Consumers in the EU25

countries indirectly contribute for about 20 per cent to

the desiccation of the Aral Sea.

A.K. Chapagain et al, the water footprint of

cotton consumption, Research Report Series No. 18, Unesco September 2005

14

Viscose fibres

World production : 14% of artificial fibres (clothes, tires).

Invented by French scientist Hilaire de Chardonnet in 1891. Three British

scientists, Charles Frederick Cross, Edward John Bevan, and Clayton Beadle

patented the process in 1902.

Preparation: pulp is dissolved in caustic soda and it is shredded and allowed to

age. The aged pulp is then treated with carbon disulfide to form a yellow-

colored cellulose xanthate, which is dissolved in caustic soda again. Spinning

then regeneration (acid media or temperature).

Cellulose cellulose xanthate cellulose

Pollution: carbon disulfide and other by-products of the process.

15

Which solutions?

Decrease environmental pressure of cotton growing

« Coton bio »

Decrease pollution of viscose process

Possible but very costly

Use other sources

Bacterial cellulose ??

Use other solvents

Only one is industrialized (Lyocell process)

Need to find other solvents

16

A: Introduction: cellulose fibres

B: Present fibres: properties and difficulties

C: Fibres coming from new solvents

D: Conclusions

17

New solvents for processing cellulose fibres

Three main possibilities

• Lyocell process (not really new)

• NaOH-water

• Ionic liquids

18

Solution preparation Pumping (up to 30bars)

regeneration finishing

Air gap treatment

Filtering and spinning (through spinneret :40-400mm)

O

C

N

H

LYOCELL Process

cellulose processing in N-methylmorpholine-N-oxide / water

19

From Chanzy et al, Journal of Applied Polymer Science, 1983

RAMIE FIBRES

A: Dissolution

B: Only irreversible

swelling

C: Only reversible

swelling

D: Inactivity

phase diagram NMMO – H2O

D C B A

Dissolution, swelling and inactivity zones

20

Lyocell fibres: spun from a NMMO solution

Comparison with viscose fibres in both dry and wet states :

higher tensile strength

higher modulus

higher tear strength

lower strain at break

The textile properties in the wet state are very good.

BUT: high tendency to fibrillation

21

0,0

10,0

20,0

30,0

40,0

50,0

60,0

Percentage

(%)

<50 nm [50-100 nm] [100-500 nm] [0.5-1 µm] [1-2 µm] >2 µm

Ranges of fibril diameters

0,0

10,0

20,0

30,0

40,0

50,0

60,0

Percentage

(%)

<50 nm [50-100 nm] [100-500 nm] [0.5-1 µm] [1-2 µm] >2 µm

Ranges of fibril diameters

0,0

10,0

20,0

30,0

40,0

50,0

60,0

Percentage

(%)

<50 nm [50-100 nm] [100-500 nm] [0.5-1 µm] [1-2 µm] >2 µm

Ranges of fibril diameters

0,0

10,0

20,0

30,0

40,0

50,0

60,0

Percentage

(%)

<50 nm [50-100 nm] [100-500 nm] [0.5-1 µm] [1-2 µm] >2 µm

Ranges of fibril diameters

warm humid air gap and precipitated in water

cold dry air gap and precipitated in water

Normal atmosphere and precipitated in water

normal atmosphere and precipitated in NaOH

22

Under mechanical stress, in wet state, fibres fibrillate: fibrillation is

linked to the strong orientation of cellulose chains.

Dangerous process

Environmentally safe (99.8% solvent recovery)

Source: Ducos et al., 2005

23

Net NREU (GJ/t fibre), Cradle-to-factory gate

plus post-consumer waste incineration

with energy recovery (recovery rate = 60%primary energy)

Cotton (U

S&CN)

PET (W.Europe)

PP (W.Europe)

PLA fibre, w

ithout w

ind

PLA fibre, w

ith w

ind

Lenzing Viscose Asia

Tencel, Austria

Lenzing Modal

Tencel, Austria

, 2012

Lenzing Viscose Austria-40

-20

0

20

40

60

80

100

Net NREU

Net NREU, lower range

Net NREU, higher range93

85

62

43

2536 22 19

-10 -14

-29

-9 -9 -9 -9 -9

Cradle-to-factory gate

Recovered energy from

waste incineration

(energy recovery rate 60%)

Cotton: 26

-11 -11

66

39

Li Shen and Martin Patel

Utrecht University

24

Net Global Warming Potential (t CO2 eq./t fibre), Cradle-to-factory

gate plus post-consumer waste incineration

with energy recovery (recovery rate = 60%primary energy)

Cotton (U

S&CN)

PET (W.Europe)

PP (W.Europe)

PLA fibre, w

ithout w

ind

PLA fibre, w

ith w

ind

Lenzing Viscose Asia

Tencel, Austria

Tencel, Austria

, 2012

Lenzing M

odal

Lenzing Viscose Austria

-1

0

1

2

3

4

5

6

Net GWPlower range

Net GWPhigher range

-0.3

GHG emissions from waste

incineration (energy recovery

rate: 60%)

Cradle-to-factory gate GWP

(including carbon sequestration)

2.0

1.1

4.0

1.5

2.7

1.5 3.9

0.9

1.2

0.9

0.15

0.9

0.03

0.9

-0.25

0.9

Cotton: 3.1

2.6

0.9

1.2

1.2

25

Cotton (U

S&CN)

Lenzing V

iscose A

sia

PET fibre

(W.E

U)

PP fibre

(W.E

U)

Tencel, Austri

a

Lenzing M

odal

Lenzing V

iscose A

ustria

Tencel, Austri

a 2012

NO

GE

PA

Sin

gle

-sc

ore

po

ints

(Fir

st

no

rma

lise

d t

o W

orl

d 1

995

)

0

1050

60

70

80

90

100

Global warming

Abiotic depletion

Ozone layer depletion

Human toxicity

Fresh water ecotoxicity

Terrestrial ecotoxicity

Photochemical oxidation

Acidification

Eutrophication

Single-score result

NOGEPA weighting factors (normalised to world)

1 tonne fibre, cradle-to-factory gate, cotton =100

Weighting factors (NOGEPA)

Climate Change 32

Abiotic depletion* 8

Ozone layer depletion 5

Human toxicity 16

Fresh water ecotoxicity 6

Terrestrial ecotoxicity 5

Photochemical oxidation 8

Acidification 6

Eutrophication 13

Total 99

Source: Huppes et al (2003),

except for abiotic depletion

(marked with *), which is not

excluded by Huppes et al. and

is determined based on own

estimation.

26

Na-OH Process

• Look simple: NaOH + water + cellulose at low

temperatures (- 5°C)

• No pollution

• Invented during the 80’s by Japanese scientists

• Huge amount of research in Asia (mainly China

now) and Europe

• But suffers major drawbacks

27

Buckeye VFC

swollen in 8 % NaOH – water -5°C

Borregaard VHF

swollen in 8% NaOH – water -5°C

Bad, even very bad solvent

In 8% NaOH-water at -5°C under agitation, cellulose dissolves,

but not very well, with many undissolved parts remaining.

Solutions are gelling

28

Need to increase solubility and decrease gelation

• Need complex pre-treatments

of cellulose pulps

• Need adding additives like ZnO

of urea

Un-treated solution

• Not yet ready, if ever

0.01

0.1

1

10

0 300 600 900time, min

G', G'', Pa

G', 20°C

G'', 20°C

G'', 25°C

G'', 25°C

tgel tgel

5% cellulose in 9%NaOH/water

29

Cellulose solvents:

Dissolution:

[7% -10%] NaOH

Intensive mixing for 2 hours at [-6°C - +1°C]

- NaOH-water

- Imidazolium-based Ionic Liquids:

, melting point: ~60°-70°C , room temperature liquid

Dissolution: heating and stirring for several hours

- Cellulose • Microcrystalline cellulose = “cellulose”, DP 170

• “other” native celluloses: DP 300, 500, 1000

• bacterial cellulose, DP 4420

30

Ionic liquids

Ionic liquids (IL): new green cellulose solvents

- non-toxic (is it sure ?) and non-volatile

- high termal stability

- possible to dissolve high cellulose concentrations without

pre-activation

- can be tuned due to modifications in anions or cations

- expensive, but possible to recycle

31

Ionic liquids

Imidazolium-based Ionic Liquids:

, melting point: ~60°-70°C , room temperature liquid

No commercial product yet

32

A: Introduction: cellulose fibres

B: Present fibres: properties and difficulties

C: Fibres coming from new solvents

D: Conclusions

33

What is the future of cellulose fibres ?

• It must be proved that they offer a REAL advantage

over other fibres in terms of environment footprint.

• New, water-based solvents must be designed.

• Recent advances about hydrophobicity of cellulose

offer reasons to hope that new solvents can be

designed.

34

CEMEF

www.cemef.mines-paristech.fr

www.epnoe.eu