Nanocellulose materials

(1)

- Preparation, properties, uses

The Finnish Centre of Nanocellulosic Technologies

Timo M. Koskinen, UPM-Kymmene Ltd, Pia Qvintus,

Anne-Christine Ritschkoff, Tekla Tammelin & Jaakko Pere,

(2)

Pulp & paper industry after

year 2000

Paper production

Energy 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

Business environment

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

Conclusion

(3)

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.

(4)

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.

(5)

European vs. North American

approach

Europe: Focus on NFC/MFC

Long fibrils

Amorphous and crystalline

parts 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

(6)

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

(7)

Nanocellulose – New innovations

for the forest sector

Overall objectives

To develop technoeconomically

feasible, industrial scale

manu-facturing techniques for mass

production of cellulose

nano-materials

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

(8)

Vision: Nanocellulose as part of

biorefinery

Processing

Refining

Tailoring

Industrial pulps

Novel products

Step change/breakthrough product properties

Non-wood crop residues

Cellulose nanomaterials

Industrial pulps

(9)

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, Biomacromole cules, 8(2007)1934

(10)

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

(12)

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 to aramid fibers similar to quartz glass Cellulose I crystal form

Special properties

(13)

Manufacturing of NFC:

Operation principle of Masuko

grinder

Masuko grinder

Grindstone

(14)

Manufacturing of NFC:

Operation principle of fluidizer

Microfluidics fluidizer Cut-away view of an interaction chamber Operation principle

(15)

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 fro m s tress sweep [ P a] 0 50 100 150 200 250 300 350 G' m ax f rom st ress sweep [P a] plate-plate vane

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

(16)

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

(17)

Transparent gels by homogenization

(18)

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

(19)

Effect of drying method

Freeze drying Critical point drying

20 m

(20)

Methods of

functionalization

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

(21)

Changing the properties of

nanocellulose materials by

modification

Functionalization Hydrophobicity Charge (+/-) Specific interactions

Cellulose nanofibres and whiskers

Characterization Rheology Charge density Interactions Microscopy Chemical composition Small scale testing Compatibility Strength

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

(22)

Surface modification of NFC by

silylation

XPS analysis indicate increase in silica content Increase in the relative abundance of C-C and C-Si bonds

AFM analysis confirm

the successful surface modification

Maintain the nano-fibrillar structure 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 images

(23)

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

0 20 40 60 80 100 120 140 160 180 0 50 100 150 200 Time (s) Cont a ct a ngl e of w at er DS=0.6 DS=1

Tammelin/VTT, Johansson and Österberg/Aalto University School of Science and Technology

(24)

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) applications

Composite materials (10), Food products (2), Nonwovens (2), Filter materials (2), Paper and board (2), Paper and

board coatings (2)

Applications for microfibrilled

cellulose

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(26)

Potential applications of

NFC/MFC/CNC*

NFC/CNC/MFC can be used for:

Advanced building products

Recyclable structural and interior components for transport industry

Novel bioplastics

Fibre-reinforced composites Switchable optical films

Biocomposites for bone-repair

Additives for paints, pigments and inks Cosmetic products

Iridecent or magnetic films

Enhancement of performance of forest products such as building materials, paper, board and packaging….

… and more.

=> various functionalization methods and processes are needed *ArboraNano/FPInnovations