Standardization of micro- and nanocelluloses
Transcript of Standardization of micro- and nanocelluloses
Standardization of micro- and nanocelluloses
Workshop on International Standards for NanocelluloseJune 9th, 2011,
Ulla Forsström and Erkki HellénVTT Technical Research Centre of Finland
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Formulating the Finnish view with g
Main national research activities
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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
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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
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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
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4
5
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Microfibrillated
Interest area
Overall dimensions in macroscale, fine structure in nanoscale
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1
2
Image area 1x1 μm Image area 2x2 μm
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15
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Charge/mass
C ll id l di i
Image area 2x2 μm
0
5
C ll id l di i
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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
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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
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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
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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.
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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
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• Amount of nanomaterial
Basic characteristics given by combination of viscosity combination of viscosity, transmittance and microscopy
Sneck A., 2011 TAPPI Int. Conference on
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,Nanotechnology for Renewable Materials
Basic characterization - Important physical and chemicalproperties of fibrillated celluloses
• Appearance, dimensions, aspect
properties of fibrillated celluloses
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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
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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
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• 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
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• 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
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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
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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
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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
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Please contact: [email protected]
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.
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DateAction FA0904 Food and Agriculture