BIObased polymer and composite group
Centre de Mise en Forme des Matériaux
Materials Forming Center
Cellulose and polysaccharide solutions
Contacts:
[email protected]
[email protected]
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Cellulose and polysaccharide solutions
Cellulose is the most abundant natural polymer on Earth
but it is difficult to dissolve and it is not fusible
Goal of research
• Understand cellulose biosynthesis.
• Understand dissolution mechanisms of cellulose coming
from various sources. Methods to improve dissolution.
• Study solution thermodynamics and rheology in new
solvents.
• Control cellulose coagulation.
Cellulose structuration in cell walls during
biosynthesis
Goal: to understand the organisation behaviour of cellulose fibres in
the cell wall
•
•
•
•
How are cellulose chains organizing right after exiting from membrane?
What is the distance membrane – wall?
Is growth synchronised ?
What are the states right before crystallisation?
Numerical simulation of the conformations of six fibres exiting
the plasma membrane during biosynthesis
(with B Monasse, CEMEF)
validation
Collaboration Candace Hagler
Photo C. Hagler & M Grimson
[email protected]
Cellulose fiber swelling and dissolution
Goal: to understand the swelling and dissolution of cellulose fibres
and to relate them to the fibre morphology
Dissolution behaviour of native cellulose fibres is
controled by the existence of different walls made
during biosynthesis. The picture shows how the
primary wall rolls around a swelling secondary
wall, making sort of balloons.
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Influence of enzymatic and/or chemical treatments
for improving cellulose dissolution
Goal: to improve and find new activations of cellulose pulp:
- treatment with Nitren (dissolution of xylan)
- enzymatic treatment (dissolution of the primary wall)
- influence of tension
Disolution yield (%)
Softwood pre-hydrolysis kraft
60
40
20
250
300
350
400
450
500
550
600
Cuen viscosity (ml/g)
15
10
20
5
10
0
0
starting pulp 3%
Influence on enzymatic
treatments on solubility
5%
20
15
10
5
0
Mannose content of the pulp (%)
Softwood bleached sulfite
80
20
Xylose contentof the pulp (%)
Hardwood kraft
Glucose content of the pulp (%)
100
100
95
90
85
80
Glucose content
Xylose content
Mannose content
7%
Nitren concentration
Influence of nitren treatment
on pulp composition.
[email protected]
Dissolution of cellulose in NaOH-water
Goals:
- Mechanisms of cellulose dissolution in aqueous NaOH solutions.
- Influence of additives (urea, ZnO) on the properties of cellulose-NaOH
solutions (gelation, hydrodynamic properties).
Limit of cellulose dissolution in NaOH/H2O:
minimum 4NaOH per 1 AGU
eutectic mixture
• No influence of additives of the cellulose hydrodynamic volume
• Thermodynamic quality of solvent decreases with temperature ↑
water
DSC thermograms of cellulose-7.6%NaOH-water
[email protected]
[email protected]
Cellulose-ionic liquid solutions
Goals:
- To characterise the properties of cellulose-imidazolium-based ionic liquid solutions:
flow, visco-elasticity, solvent quality, comparison with other cellulose solvents.
- To understand the influence of non-solvent addition: water, DMSO.
140 intrinsic viscosity, mL/g
120
Cellulose-EMIMAc
100
80
60
40
Cellulose-BMIMCl
20
0
0
50
100
T, °C
Decrease of solvent thermodynamic quality with
temperature increase
-
Cellulose aggregation in EmimAc-water followed by coagulation
- No influence of DMSO on cellulose hydrodynamic size
[email protected]
Starch-ionic liquid solutions
Goals:
- To understand the behaviour of starch granule in ionic liquid.
- To characterise starch-ionic liquid solution visco-elastic properties.
Comparison of waxy starch dissolution and gelatinisation in EMIMAc, water and EMIMAc-water
dry starch granules
dissolution in EmimAc
swelling and dissolution in 25%EmimAc–75%water
Beginning of
Temperature of
Total dissolution
dissolution or
complete
time, min
gelatinization, °C
dissolution, °C
100% EMIMAc
75 – 80
100
16
75%EMIMAc-25%water
54 – 56
76 – 78
8
50%EMIMAc -50% water
54 – 56
76 – 78
8
25%EMIMAc-75%water
75 - 77
100
12
100% water
65 – 70
95-100
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- No starch gelatinisation in
ionic liquid.
- Water strongly accelerates
starch dissolution.
[email protected]
Rheology of polysaccharide solutions
Goal:
understand flow behaviour in relation with polymer chain structure,
solvent-polymer interactions and solution morphology
Elasticity of cellulose derivative solutions
measured by shear recovery methods
1.10

100Pa
r = 0.07
1.08
1.06
A- Interface elasticity between a HPC
solution and a molten polymer
Low elastic recovery
1.04
1.02
1.00
0.98
0
10
20
30
time (s)
0.20

Pure HPC 100 Pa r = 0.018
HPC, Mw = 9.5x10
45% in water
0.15
B- entropic elasticity coming from
the change of chain
conformations during shear
Moderate elastic recovery
4
10 Pa
20 Pa
50 Pa
100 Pa
200 Pa
500 Pa
0.10
0.05
0.00
0
200
400
600
800
6
time (s)
1000
HPC, Mw = 9.5x10
55 % in water

4
5
C- elasticity coming from
orientational defects in liquid
crystalline solutions
Very high elastic recovery
10 Pa
20 Pa
4
50 Pa
3
2
1
0
0
1000
2000
time (s)
3000
[email protected]
Low derivatized hydroxyethylcellulose cellulose
Goals:
- Influence of substitution on rheological properties and gelation of HEC solution in
NaOH-water solvent
- Properties of HEC spun fibers
-
Higher dissolution limit
Solution much more stable
- Gelation is strongly delayed as compared to cellulose
- Another kinetics
HEC
cellulose
•
Grafted hydroxyethyl groups decrease the probability of formation of inter- and intra-chain hydrogen
bonds and prevent cellulose aggregation.
•
Weak substitution can be a way of stabilization of cellulose-NaOH solutions.
[email protected]
[email protected]
CEMEF
www.cemef.mines-paristech.fr
Ecole des Mines de Paris / Mines ParisTech
Centre de Mise en Forme des Matériaux
CNRS UMR 7635
Rue Claude Daunesse
CS 10207
06904 Sophia Antipolis cedex - France
www.epnoe.eu
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