Nano Cellulose Center Teknokeskiviikko 20-4-2011
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Transcript of Nano Cellulose Center Teknokeskiviikko 20-4-2011
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Nanocellulose materials- Preparation, properties, uses
The Finnish Centre of Nanocellulosic Technologies
Timo M. Koskinen, UPM-Kymmene Ltd, Pia Qvintus, Anne-Christine Ritschkoff, Tekla Tammelin & Jaakko Pere, VTT Technical Research Centre of Finland
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Pulp & paper industry after year 2000
Paper productionEnergy costs increaseShortage of wood and all fibreEconomy of scale in paper products does not work any more, especially in EuropeCapital intensive industry – difficult to be flexibleSensitive to economical fluctuation
Business environmentShift to more added value paper products is no more competitive approach in Europe and in North AmericaOvercapacity and low prices in EuropeIncrease in demand and increase in production outside Central Europe: low prices and less export from Europe
ConclusionCompletely new initiatives are needed
Present
Research on micro / nano fibrillated cellulose (MFC / NFC) and cellulose nano crystals (CNC) has gradually increased since year 2000.
Today there is on-going all over the world a substantial amount of research on nano cellulose.
Nanocellulose research groups
SunPap – EU-project, 2009-2012 (nanocellulose as a driver)
SustainComp – EU-project (nanocellulose included)
KTH, L Berglund, T Lindström, Sweden
Univ. of Kyoto, Yano & al, Japan
Univ. of Tokyo, Isogai & al, Japan
Univ. of North Carolina & PennState University, U.S.A.
EMPA, Switzerland
ArboraNano, Paprican, Canada
Agenda 2020 (2 parts: biorefinery & nanocellose), U.S.A.
Other groups in Sweden, Germany, Norway, etc.
European vs. North American approach
Europe: Focus on NFC/MFC
Long fibrils
Amorphous and crystallineparts both in fibrils
Mechanical process, or chemi-
mechanical
No self assembly
Strongly shear thinning -rheology depends on the manufacturing process
N.A. - Focus on CNC
Whiskers – short
Crystalline
Chemical process
Acid hydrolysis
Self assembly possible
Defined rheology
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Combines the competencies of Aalto University School of Science and Technology, VTT and UPM:
Profound and cross-disciplinary basic research Multi-technological applied research and high level project administration Product development and techno-economical expertise
Sets up a project portfolio which addresses production technology, physical and chemical modification, characterization and novel applications.
Combines capabilities and resources to create and govern of needed versatile IPR.
Annual volume ca. 40 person years – 5 M€.
The Finnish Centre for Nanocellulosic technologies – Est. March 2008
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Nanocellulose – New innovations for the forest sector
Overall objectivesTo develop technoeconomicallyfeasible, industrial scale manu-facturing techniques for mass production of cellulose nano-materialsTo generate new markets for (ligno)cellulosic raw material and renew the potential of existing products
Added value from nanocelluloseIncreased functionality, improved mechanical properties, novel optical and conductivity properties, light weight high performance structuresNovel forest based products
Breakthroughs
Vision: Nanocellulose as part of biorefinery
ProcessingRefiningTailoring
Industrial pulps
Novel products
Step change/breakthrough product properties
Non-wood crop residues
Cellulose nanomaterials
Industrial pulps
Biorefining by-products
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From the cellulose molecule to a three – a perfect example of self-assembly
Fibres• Width 30-40 µm• Length 1-3 mm
Fibrils• Width 5-30 nm• Length over 1 µm
Esau, Anatomy of seed plants, 1977, Wiley, NY
Aalto University School of
Science and Technology,
Myllytie
Pääkkö et al, Biomacromolecules, 8(2007)1934
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What is nanocellulose?
Preparation of nanofibrills Products
It is a natural nanomaterial that seems to give a range of opportunities to obtain superior material properties for different end-products
Esau, Anatomy of seed plants, 1977, Wiley, NY
Pääkkö et al, Biomacromolecules, 8(2007)1934
1,7% solid content
WHY?
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What is the basis?
How large a fraction of atoms are on the surface of a fiber?
40 m wood fiber, 0.002%4 nm elementary fibril, 19%
The surface atoms specify the properties
Cellulose pulp vs. NFC gel, Pääkkö 2008
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Pääkkö et al, Biomacromolecules, 8(2007)1934
Semi-crystalline extended chains
Young´s modulus 140 GPa(T. Nishino et al. J.Polym.Sci.,Part B,1995)Tensile strength 3 GPa(D.Page, F. El-Hosseiny, J.Pulp Paper Sci. 1983)Coefficient of thermal expansion 0,1 ppm/ºK(H.Yano, Seminar lecture, Otaniemi 2009)
close toaramid fibers
similar toquartz glass
Cellulose Icrystal form
Special properties
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Manufacturing of NFC:Operation principle of Masuko grinder
Masuko grinderGrindstone
Operation principle
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Manufacturing of NFC:Operation principle of fluidizer
Microfluidics fluidizer
Cut-away view of an interaction chamber
Operationprinciple
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Rheological characterization of NFC suspensions/gels => processability
1 pass
4 passes
6 passes
0
1000
2000
3000
4000
5000
6000
7000
1 4 6
Number of fluidizer passes
G' m
ax fr
om s
tress
sw
eep
[Pa]
0
50
100
150
200
250
300
350
G' m
ax fr
om s
tress
sw
eep
[Pa]
plate-platevane
1 pass 4 passes 6 passes
plate-plate:20 mm,
gap 1 mm
vane in cup:
vane 28 mm, cup 30 mm
Result is geometry dependent!
Combination of analytical tools !
Small deformation oscillatory testing – stress sweep
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Characterization – a challenge
Particle size analysis
SEM, AFM, (Cryo-) TEM
Rheology of suspension
On line –measurements
Combination of analytical tools!
SEM imaged NFC (Pere, Tammelin, Tapper/VTT)
AFM imaged fractionated NFC (Ahola, Eronen, Österberg/Aalto University School of Science and
Technology)
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Effect of refining and fluidizing on fiber dimensions
NFC after fluidizing: light microscope image (above) and cryo-TEM image (left)
P. Hiekkataipale, Aalto University School of Science and Technology
Methods offunctionalization
Chemical modification of NFC surface
Functionalzation using nanoparticles
Nanocellulose modified with inorganics and
surfactants
Biochemical modification
Enabling drying & redispersing
Nanocellulose
Functionalization of NFC using polymers
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Changing the properties of nanocellulose materials by modification
FunctionalizationHydrophobicityCharge (+/-)
Specific interactions
Cellulose nanofibres and whiskers
CharacterizationRheology
Charge densityInteractionsMicroscopyChemical
composition
Small scale testing
CompatibilityStrength
Testing of functionalized material in different applications:
Application oriented
processability of NFC material
Ideas for enhanced properties of end
products
Ideas for novel cellulose based
materials
1. Composites 2. Nanomaterial Additives
3. Porous cellulose materials
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Surface modification of NFC by silylation
XPS analysis indicateincrease in silica contentIncrease in the relative abundance of C-C and C-Si bonds
AFM analysis confirmthe successful surface modificationMaintain the nano-fibrillar structure
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Sample O 1s (%)
C 1s (%)
Si 2p (%)
C-C, C-Si (%)
DSs
NFC ref 43.8 55.5 0 2.1 NFC I 35.3 60.5 4.3 27.0 ~0.6 NFC II 31.9 62.1 5.9 35.8 ~1.0
Tammelin/VTT, Johansson and Österberg/Aalto University School of Science and Technology
NFC, ref NFC DSs ~0.6 NFC DSs ~1.0
5×5 m height images22
Water contact angle of the silylated NFC films
Silylated NFC films are hydrophobic
Nanoscale surface roughness may have effect on the contact angle values
Higher value for lower DS
Contact angle of pure NFC is <40° and the age of the water droplet is much lower
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020406080
100120140160180
0 50 100 150 200
Time (s)
Con
tact
ang
le o
f wat
er
DS=0.6DS=1
Tammelin/VTT, Johansson and Österberg/Aalto University School of Science and Technology
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Filed patent applications for nanocellulose in different end uses
Composite materials (46, 38%)Nonwovens, adsorbent webs (22, 18%)Paper and board (20, 16%)Food products (15, 13%)Paper and board coatings (10, 8%)Cosmetics and toiletry (4, 3%)Filter materials (5, 4%)Many of the granted patents have expired and many of the applications were not granted
13 %3%
18 %
4 %16 %
8 %
38 %
NFC applications
Recent (2009) applicationsComposite materials (10), Food products (2), Nonwovens (2),Filter materials (2), Paper and board (2), Paper and board coatings (2)
Applications for microfibrilled cellulose
Data collected by Dr. Juha Merta, Aalto University School of Science and Technology24
Potential applications of NFC/MFC/CNC*
NFC/CNC/MFC can be used for:
Advanced building productsRecyclable structural and interior components for transport industryNovel bioplasticsFibre-reinforced compositesSwitchable optical filmsBiocomposites for bone-repairAdditives for paints, pigments and inksCosmetic productsIridecent or magnetic filmsEnhancement of performance of forest products such as building materials, paper, board and packaging….… and more.
=> various functionalization methods and processes are needed
*ArboraNano/FPInnovations
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Safety of nanomaterials
Occupational safety issuesAre there nanomaterials in the work space air?How to protect oneself?The Finnish Institute of Occupational Health has made some initial evaluations
Product safety – EU comissionOfficial demands are application specificCellulose nanomaterials are not in REACH, yetRegulations for nanotechnology products in general will be tighter in a near futureBest to be proactive and collaborative while the new regulations are being developed
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Acknowledgements
Following persons are gratefully acknowledged for their contribution to this presentation
VTT: Unto Tapper, Martina Lille & Sauli Vuoti
Aalto University School of Science and Technology, Department of Forest Products Technology: Tuomas Hänninen, Eero Kontturi, Monika Österberg & Janne Laine
Aalto University School of Science and Technology, Molecular Materials: Panu Hiekkataipale & Olli Ikkala
The Finnish Centre for Nanocellulosic Technologies and UPM-Kymmene Ltd is gratefully acknowledged for the financial support.
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