Nano Cellulose Center Teknokeskiviikko 20-4-2011

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Nanocellulose materials - Preparation, properties, usesThe Finnish Centre of Nanocellulosic TechnologiesTimo M. Koskinen, UPM-Kymmene Ltd, Pia Qvintus, AnneChristine Ritschkoff, Tekla Tammelin & Jaakko Pere, VTT Technical Research Centre of Finland


Pulp & paper industry after year 2000Paper productionEnergy costs increase Shortage of wood and all fibre Economy of scale in paper products does not work any more, especially in Europe Capital intensive industry difficult to be flexible Sensitive to economical fluctuation Shift to more added value paper products is no more competitive approach in Europe and in North America Overcapacity and low prices in Europe Increase in demand and increase in production outside Central Europe: low prices and less export from Europe Completely new initiatives are needed

Business environment



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 groupsSunPap EU-project, 2009-2012 (nanocellulose as a driver) SustainComp EU-project (nanocellulose included) KTH, L Berglund, T Lindstrm, 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/MFCLong fibrils Amorphous and crystalline parts both in fibrils Mechanical process, or chemimechanical No self assembly Strongly shear thinning rheology depends on the manufacturing process

N.A. - Focus on CNCWhiskers short Crystalline Chemical process Acid hydrolysis Self assembly possible Defined rheology

The Finnish Centre for Nanocellulosic technologies Est. March 2008Combines 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.


Nanocellulose New innovations for the forest sectorOverall objectives To develop technoeconomically feasible, industrial scale manufacturing techniques for mass production of cellulose nanomaterials To generate new markets for (ligno)cellulosic raw material and renew the potential of existing products Added value from nanocellulose Increased functionality, improved mechanical properties, novel optical and conductivity properties, light weight high performance structures Novel forest based products Breakthroughs7

Vision: Nanocellulose as part of biorefineryNovel products Step change/breakthrough product propertiesCellulose nanomaterials Biorefining by-products Processing

Refining Tailoring

Non-wood crop residuesIndustrial pulps

Industrial pulps8

From the cellulose molecule to a three a perfect example of selfassemblyFibres Width 30-40 m Length 1-3 mmAalto University School of Science and Technology, Myllytie

Pkk et al, Biomacromole cules, 8(2007)1934


Width 5-30 nm Length over 1 mEsau, Anatomy of seed plants, 1977, Wiley, NY


What is nanocellulose?

Preparation of nanofibrills


Esau, Anatomy of seed plants, 1977, Wiley, NY

Pkk et al, Biomacromolecules, 8(2007)1934

1,7% solid content

It is a natural nanomaterial that seems to give a range of opportunities to obtain superior material properties for different end-products WHY?10

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 properties11

Cellulose pulp vs. NFC gel, Pkk 2008

Special properties

Pkk et al, Biomacromolecules, 8(2007)1934

Semi-crystalline extended chainsYoungs 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/K (H.Yano, Seminar lecture, Otaniemi 2009) close to aramid fibers similar to quartz glass

Cellulose I crystal form


Manufacturing of NFC: Operation principle of Masuko grinder

Operation principle

Masuko grinder Grindstone13

Manufacturing of NFC: Operation principle of fluidizer

Operation principle Microfluidics fluidizer

Cut-away view of an interaction chamber


Rheological characterization of NFC suspensions/gels => processabilitySmall deformation oscillatory testing stress sweep7000 350

plate-plate:20 mm, gap 1 mmG' max from stress sweep [Pa]

6000 G' max from stress sweep [Pa]


1 pass

5000 plate-plate 4000 vane



vane in cup:vane cup 28 mm, 30 mm



4 passes





0 1 4 Number of fluidizer passes 6


6 passes

1 pass

4 passes

6 passes

Result is geometry dependent! Combination of analytical tools !


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, sterberg/Aalto University School of Science and Technology)


Transparent gels by homogenization

Before fibrillation

After fibrillation

Concentration 0.8%


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


Effect of drying method



Freeze drying

Critical point drying



Functionalization of NFC using polymers

Methods of functionalization

Chemical modification of NFC surface

Functionalzation using nanoparticles


Nanocellulose modified with inorganics and surfactants

Biochemical modification

Enabling drying & redispersing


Changing the properties of nanocellulose materials by modificationCellulose nanofibres and whiskers

Functionalization Hydrophobicity Charge (+/-) Specific interactions

Characterization Rheology Charge density Interactions Microscopy Chemical composition

Small scale Compatibility Strength


Application oriented processability of NFC material

Ideas for enhanced properties of end products

Ideas for novel cellulose based materials

Testing of functionalized material in different applications:1. Composites 2. Nanomaterial Additives 3. Porous cellulose materials


Surface modification of NFC by silylation

Sample NFC ref NFC I NFC II

O 1s (%) 43.8 35.3 31.9

C 1s (%) 55.5 60.5 62.1

Si 2p (%) 0 4.3 5.9

C-C, C-Si (%) 2.1 27.0 35.8


~0.6 ~1.0

AFM analysis confirm

XPS analysis indicate increase in silica content Increase in the relative abundance of C-C and C-Si bonds the successful surface modification Maintain the nanofibrillar structure

NFC, ref

NFC DSs ~0.6

NFC DSs ~1.0

Tammelin/VTT, Johansson and sterberg/Aalto University School of Science and Technology22

55 m height images

Water contact angle of the silylated NFC films180

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 various functionalization methods and processes are needed *ArboraNano/FPInnovations


Safety of nanomaterials

Occupational safety issues

Are there nanomaterials in the work space air? How to protect oneself? The Finnish Institute of Occupational Health has made some initial evaluations Official demands are application specific Cellulose nanomaterials are not in REACH, yet Regulations for nanotechnology products in general will be tighter in a near future Best to be proactive and collaborative while the new regulations are being developed

Product safety EU comission



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 Hnninen, Eero Kontturi, Monika sterberg & 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.


Thank you for your attention!