Standardization of micro- and nanocelluloses

Workshop on International Standards for NanocelluloseJune 9th, 2011,

Ulla Forsström and Erkki HellénVTT Technical Research Centre of Finland

1

Formulating the Finnish view with g

Main national research activities

3

Nanocelluloses – A Class of Nanomaterials

– Examples of Raw Materials:Wood Pulp Bacteria Straw Sugar Beet Banana Potato

– Examples of Production Methods:Examples of Production Methods:

Grinding, Homogenizer, Intensification, Hydrolysis / Electrospinning, Ionic liquids

4

Top-Down / Bottom-Up

Wide variety of micro- and nanofibrillar celluloses …

Novel products

Step change/breakthrough product properties

Cellulose nanomaterials

Industrial

Processing

Biorefining by-productsIndustrial

sidestreams, wastes

RefiningTailoring

Industrial pulps

Non-wood crop residues Industrial pulps Wood, harvesting residues

…leading to a wide range of applicationsg g pp

Important aspects for standardization

• International standardization of micro- and

p p

nanocelluloses needed to support commercialization

• Open international standard development

• No national standards

• First need to agree on terminology and start to standardize measurement methodsstandardize measurement methods

• No need to standardize products: different micro- or nanocelluloses

• Important to check already standardized measurement methods, some of which can be applied also to micro-and nanocellulosesand nanocelluloses

7

L th

Wide variety of cellulosic fibers – another view Length

FTech

MCC

Wood pulp fiber

Interest area: Microfibrillated cellulose

e in

crea

es

DaicelCelish KY-100G

RettenmeierMFC

Microfibrillated cellulose

on d

egre

e

RettenmeierUFC 100

TEMPO

Innventia II gen

Fibr

illat

io

Yano

NCCChemically modified grades

Width

Wide variety of different celluloses – suggestion for classification

Size/Dimensions/Branching Bacterial celluloseScale bar: 20 μm

Chain or rod-like structureAll dimensions in nanoscale

Nanowhiskers Nanofibres

v vvvvvv Ribbon-like

structureOverall dimensions in

v

All dimensions in nanoscale

Branched structureOverall dimensions in

Nanofibrillated macroscale, fine structure in nanoscale

3

4

5

6

Microfibrillated

Interest area

Overall dimensions in macroscale, fine structure in nanoscale

0

1

2

Image area 1x1 μm Image area 2x2 μm

10

15

20

Charge/mass

C ll id l di i

Image area 2x2 μm

0

5

C ll id l di i

9

Polyelectrolyte-likeWood-fibre like

Decreasing surface charge

Colloidal dispersionColloidal dispersion

Interest area

Suitable characterization methods depend on fibril type

Size/Dimensions/Branching Bacterial celluloseScale bar: 20 μm

Chain or rod-like structureAll dimensions in nanoscale

Nanowhiskers Nanofibres

v vvvvvv Ribbon-like

structureOverall dimensions in

v Set 3

Set 4 5All dimensions in nanoscale

Branched structureOverall dimensions in

Nanofibrillated macroscale, fine structure in nanoscale

3

4

5

6

Microfibrillated

Set 1Set 2

Set 4,5…

Overall dimensions in macroscale, fine structure in nanoscale

0

1

2

Image area 1x1 μm Image area 2x2 μm

10

15

20

Charge/mass

C ll id l di i

Image area 2x2 μm

0

5

C ll id l di i

10

Polyelectrolyte-likeWood-fibre like

Decreasing surface charge

Colloidal dispersionColloidal dispersion

Starting points for standardization

• Fibrillated, mechanically manufactured micro- and

g p

nanocelluloses form a specific subgroup of celluloses• Distinct from crystalline grades

• Terminology should agree with existing standards and help in defining relevant groups of cellulose fibers• Branched/ribbon-like• Micro/nano• Crystalline/including amorphous parts• Rigid/flexible• Chemically modified/unmodified

• Different characterization methods required for different

11

qtypes of cellulose materials

Characterization methods used for in-organic and synthetic nanomaterials are not directly applicable to

h l f f b ll d

y y ppfibrillar celluloses

• The main population of fibrillated celluloses consists of particles longer than 1 µm => Challenging!

• For example: In NanoSight system the longest fibres cover signals from smaller particles.p

• However after removing the longest fibres, the NanoSight can measure shorter NFC particlesshorter NFC particles.

12

Characterization methods working well for micro-and nanofibrillated celluloses

• Dry matter content

and nanofibrillated celluloses

Standards exist Dry matter content

• pH

• Brightness

Standards exist

Brookfield RVDV I Prime• Brightness

• Low shear viscosity

T itt

RVDV-I Prime viscometer withvane shape spindles

• Transmittance

• Microscopic methods (OM/LM, SEM, TEM, AFM)

• X-ray scattering/diffraction (WAXS, SAXS, XRD)

• CentrifugationDevelopment workneeded

13

• Amount of nanomaterial

Basic characteristics given by combination of viscosity combination of viscosity, transmittance and microscopy

Sneck A., 2011 TAPPI Int. Conference on

14

,Nanotechnology for Renewable Materials

Basic characterization - Important physical and chemicalproperties of fibrillated celluloses

• Appearance, dimensions, aspect

properties of fibrillated celluloses

50

60 MasscolloiderFluidizerCarboxymethylationratio, branching degree by

microscopy

• Amount of nanomaterial 10

20

30

40

%

CarboxymethylationTEMPO oxidation

Amount of nanomaterial (nano/non-nano, %)

• Average particle size, particle size

0

10

0 5 10 15 20 25 30 35 40 45 50Dry fibril width, nm

distribution of the nano fraction

• Specific surface area Manual analysis of FE-SEM images: dry fibril widthPöhler,T. et. al. Int. Conf. Nanotech 2010• Crystallinity (rigidity, flexibility)

• Surface charge, chemistry

Nanotech. 2010

15

• Dissolved (colloidal) substance (amount, quality) Date

Testing for environmental, health and safety aspect of fibrillated celluloses examples of standards/guidelines

• Cytotoxicity tests:

fibrillated celluloses, examples of standards/guidelines

• Acute cytotoxicity assays (HTD- and TPC-tests) according to ISO 10993-5

• RNA-synthesis inhibition tests EN 15845 “Determination of RNA synthesis inhibition tests EN 15845 Determination of Cytotoxicity”

• Genotoxicity tests:

• Ames test, OECD guideline (OECD 471, 1997)

• OECD guidelines for in vitro micronucleus tests (e.g. OECD 487, 2010)

• Immunotoxicity tests:

• No official standards for immunotoxicological tests

16

• Ecotoxicity tests:

• ISO 6341(1996) and ISO/DIS 21338 (2009)Date

Published safety testing data of micro-and nanocellulosesand nanocelluloses

Pitkänen et al., Int. Conf. Nanotech. 2010Cytotoxicological analysis:N i di ti f t i it f d

4045

%)

Sample Cytotoxicity Sublethaleffects

No indications of toxicity found

20253035

eath

rat

e (%

HTDHepa-1

HTDHaCaT

HTDHeLa229

RNA synthesis inhibition

assay

CTR 30 100 300 30 100 30005

1015

µg/mlC

ell d

e

Whisker-type UFC

No changes in cells’

morphology

No changes in cells’

morphologyNot tested Not tested

CTR 30 100 300 30 100 300 µg/mlMCCMFC

Fibrillar NFCNo changes

in cells’ morphology

No changes in cells’

morphology

No changes in cells’

morphology

Did not reduce mRNA synthesis in HeLa229 cells

Vartiainen et al, Cellulose (2011) 18:775–786Immunotoxicological analysis:No indications of toxicity found

17

o d cat o s o to c ty ou d

Material specifications to support commercializationp pp

• Basically similarly to wood fibers cf. TC-6 paper, board and pulps

Ch i i h d S f h h d

and pulps

• Some development work needed

Property Characterization method Apparatus Satus of the method

Dry matter content According to standard Ready for standardization

pH According to standard Ready for standardizationstandardization

Brightness According to standard Development needed on sample preparation

Size range Light scatteringFiber analysator

Nanosight, N5

Development neededFiber analysator N5

FiberLab

Rheology Low shear viscosity, yield stress Brookfield Ready for standardization

Chemical purity, Fiber analytical methods GC, MS Ready for use

18

composition

Conclusions

• Important to identify the needs for standardization

• Companies, global view

• People from ”Finnish” companies and research institutes are willing to participate in international standardization of micro- and nano-celluloses

• Information for standardization already available

• Several research projects producing more info for Several research projects producing more info for standardization on-going, some projects close to demonstration/scale-up phase

19

Why to standardize?y

• Important benefits:

• Suitability of products and processes for their intended purpose

• Prevention of barriers to trade

• Facilitation of technological cooperation

Active discussion about best characterization and safety t ti th d d i t ti l t ki d dtesting methods and international networking needed

Next collection date 30 September 2011

Pl t t ll f t @ tt fi

20

Please contact: ulla.forsstrom@vtt.fi

COST Action FA0904 “Eco-sustainable food packaging p g gbased on polymer nanomaterials”

• International Workshop “Novel nanostructured polymeric materials for food packaging and beyond” September 15-16 (Thursday-Friday), 2011 at VTT, September 15 16 (Thursday Friday), 2011 at VTT, Espoo, Finland

• The main objective of the Cost Action FA0904 is to constitute an international scientific and technology network on issues related to eco-sustainable Polymer network on issues related to eco sustainable Polymer Nanocomposites Food Packaging for the preservation, conservation and distribution of high quality and safe food.

21

DateAction FA0904 Food and Agriculture