symposium gefahrstoffe 2012 „schlema vii“ nanocellulose… · nanocellulose: possible products...
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Symposium Gefahrstoffe 2012„Schlema VII“
Nanocellulose: Possible products and experiences from health and safety studies
Tiemo Arndt, Papiertechnische Stiftung; Katja Bergroth, Juulia Rouhiainen, Pöyry Management Consulting Oy,
Atte von Wright, BioSafe - Special Laboratory Services Ltd.
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Agenda
Introduction
- Papiertechnische Stiftung
- SUNPAP
• Nanocellulose
- Sources, types and production of nanocellulose
- Properties of nanocellulose
- Current situation in nanocellulose production
• Application of Nanocellulose in Papermaking
- Possible products made out of nanocellulose
- Health and risk aspects of nanocellulose
• Summary
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• VDP – German Pulp and Paper Association• HPV – German Employers‘ Association of the
Paper, Board and Plastics Converting Industry• FPT – Paper Technology Research Association
Papiertechnische Stiftung at a glance
Founders
Facts
• Founded in 1951 • 140 employees• 2 locations
• Turnover of 15m €
Munich
Heidenau
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Financing structure of PTS
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Pilot Plants
Pilot Coater Vestra with Multilayer Curtain Coater
Complete pilot coating unit (60 cm, up to 2250 m/min) with starch and coating colour preparation
size press and film press
roll and jet applicator system with blade and rod metering
3 slot curtain coater
Super calander
Stock Prep and Paper Machine Pilot Plant
Pulper / Refiner
Pressurised stock screening / cleaning
Flotation
Pilot paper machine (simplex, duplex) (40 cm width, speed 10 m/min), NEW: inclined wire!
Size press, calander
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Scale-Up Nanoparticles in Modern Papermaking
• Large scale integrating project in the European Community‘s 7th Framework ProgramNMP-2008-1.2-1
• Three year project (2009-2012) with the budget of 9.8 mio Euro
• 22 partners from eight countries
• Coordinator is VTT Technical Research Centre of Finland
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Scale-Up Nanoparticles in Modern Papermaking
Graphical Papers(UPM, Felix Schoeller)
Packaging and Board (Stora Enso)
Technical Papers(Ahlström)
D
B
NFC Production NFC basedProcesses
Indusrydemonstrations
Assessement of Value Chain
Health and Safety
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B
NFC Production NFC basedProcesses
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B
NFC Production
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NFC Production
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NFC Production NFC basedProcesses
Indusrydemonstrations
Assessement of Value Chain
Health and SafetyR&DFactorby the Institutes
InnovationFactor
by the Industry
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Nanocellulose
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Cellulose
Plants Algae BacteriasAnimals
Cellulose Iβ Cellulose Iα
• Accounts for ~1/3 of all plant biomass
• (Chemically) very stable material, forms highly-ordered crystalline structures interrupted byamorphous regions
• 1,4-β-glucosidic bonds between the glucan molecules form a chain-molecule
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Polymer matrix of wood
Handbook of Pulp (H. Sixta ed.)
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Model of a microfibril (Fengel and Wegner 1984)
• A microfibril is a well defined structure in the plant fibre wall
cell wall layerup to 150 microlamella
microlamella1- 6 microfibrils
1 microfibril10- 20 cellulose elementary fibril
1 cellulose elementary fibril100 micelles
1 micelle40 cellulose molecule
1 cellulose molecule14.000 glucose molecules
structure unit
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The surface structure of chemical pulp fibre
Chinga-Carrasco Nanoscale Research Letters 2011, 6:417
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Types of nanocellulose
a) bacterial cellulose / Nakagaito (2005)
b) nanocrystals obtained after acid hydrolysis / Bai et al. (2009)
c) nanocellulose obtained from mechanical disintegration of sulfite pulp / Zimmermann et al. (2004)
d) nanocellulose obtained after TEMPO-oxidation and mechanicalhomogenization/ Pöhler et al. (2010)
d
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Terminology & Standardization
• Different terms of nanocellulosic products are known: microfibrillated cellulose (MFC), nanofibrillated cellulose (NFC), cellulose whiskers, cellulose nanocrystals (CNC) nanocrystaline cellulose (NCC),…
• Standardization is an on-going process
• According to a TAPPI nanocellulose standardization group following terminology isrecommended:
- Cellulose nanocrystals (CNC), and cellulose nanofibrils (CNF), and cellulosemicrofibrils (CMF)
- CNC and CNF are cellulose nano-objects
- Cellulose microfibrils and cellulose nanocomposites are cellulose nanostructuredmaterials
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Production routes of nanocellulose from wood pulp
Acid hydrolyis(e.g. sulfuric acid)
High shearhomogenization
Individual cellulosenanofibrils (CNF) Network of cellulose
microfibrils (CMF)Individual cellulose nanocrystals(CNC)
Dispersing (e.g. ultra sound)
Enzymes / Anionization / Cationization
Dialyse
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Properties of Nanocellulose
• Gel-like properties at low solid content
• Transparent films with high oxygen
barrier
• High strength properties
Siro et al. (2010), JAPS 117, 3601
Pöhler et al. (2010) 2010 TAPPI International Conference on Nanotechnology for the Forest Product Industry
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Properties of Nanocellulose
• nanocellulosic materials are from high interest not only in papermaking but also in composite materials, because of the superiormechanical properties
• high aspect ratio
• high Young Modulus at low density
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Current situation in nanocellulose production
• The paper industry sees in nanocellulose one step-stone to make new products and processes.
• Enormous interest in the industry to invest in production and application of nanocellulose.
• Homogenization technologies used in lab-scale have limited capacities to produce amounts > 100 kg/d (otro).
• In North America Cellulose Nanocrystals are more in focus.There a production plant with an expected production 1 t/d has built
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Application of nanocellulose
Rheologicalproperties
Strengthproperties
Barrierproperties
Composite materials
Nonwovens, adsorbent webs
Food productsCosmetics and toiletry
Filter materials
…and many others
Paper and board
Paper and board coatings
Paper and board coatings
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Application of nanocellulose in papermaking
• Increased strength properties, lightness of material and possibility to make tailored products are some of the interesting properties nanocellulose have. For example:
- in paper structure applications nanocellulose can be used to increase the strength of the paper.
- In paper coating nanocellulose could be used in replacing oil-based chemicals but also to make thinner and lighter products.
- Nanocellulose could allow production of functionalised paper products, e.g. antimicrobial paper
- Nanocellulose could in paper and paper board products lead to reduced raw material consumption as same properties are achieved with a lower amount of fibre raw material.
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Opportunities identified for nanocellulose in selected paper and paper board applications
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Application of nanocellulose – Risk assessment
What makes nanoparticles and nanomaterials special in regard to hazard?
Unique properties which make them interesting for commercial purposes, but also can introduce new hazards
• Nanoparticles can be distributed from the site of entry to elsewhere in the body and, to some degree, cross physiological barriers
• After exposure, many inorganic nanoparticles have been detected e.g. in brains, inner organs and embryos
• Many nanomaterials catalyse the formation of reactive oxygen species
There are a lot of results indicating various toxic effects of different inorganic nanomaterials
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Application of nanocellulose – Risk assessment
Nanocellulose has properties that may be associated with health risks
• Needle-like shape
• Biopersistence in the body
Somewhat similar properties to inorganic fibres which are known to have health risks like asbestos or carbon nanotubes
However, in contrast to rigid mineral fibres, nanocellulose
has a flexible structure, which may eliminate the safety
concerns
Source: INP Grenoble/CTP, SUNPAP Newsletter 2 in http://sunpap.vtt.fi
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Application of nanocellulose – Risk assessment
But 2010, no widely accepted risk assessment methodology existed for nanomaterials
• Method development has been challenging
• Challenges also include exposure assessment
Quite recently international organisations have taken the first steps to define an appropriate methodology e.g.
• ISO/TR 13121 Technical Report 2011: Nanomaterial risk evaluation
• EFSA 2011 Guidance on the risk assessment of the application of nanoscienceand nanotechnologies in the food and feed chain
Risk = exposure x hazard
Risk assessment is always about assessing both exposure and hazard.
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Application of nanocellulose – Risk assessment
Source: Pöyry, SUNPAP D10.1
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Application of nanocellulose – Risk assessment
In vitro tests
• to detect any cellular damage and to assess possible systemic effects
A nematode model
• to investigate potential systemic effects and neurotoxicity
Pharyngeal aspiration toxicity study with mice
• to investigate the pulmonary effects of nanocellulose
1.Screening the bioactivities of different CNFs
Cytotoxicity assays Immunotoxicological tests
Genotoxicity tests
Nematode testsSystemic effects (including neurotoxicity)
Animal tests
2. Inhalatory toxicity
Hazard assessment methodology for nanocellulose used in the SUNPAP project
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Application of nanocellulose – Risk assessment
• The suggested methodology appears suitable, and the individual tests can be adapted to meet the special challenges associated with the test material (e.g. microbial contamination, proper dispersion of the sample)
• The first results show marginal DNA-damaging effects with no dose response (Hannukainen et. al. 2011) and low cytotoxicity with no oxidative DNA damage (Hannukainen et. al 2012).
• The results are in agreement with the recently published studies on the toxicity of different micro- and nanocelluloses which do not indicate any concerns (e.g. O´Connor et.al., 2009; Rojaset.al., 2009; Kovacs et.al. 2010; Pitkänen et.al., 2010; Vartiainen et.al. 2011; Hannukainen et.al 2011, Catalan et. al 2011).
First results from the SUNPAP hazard assessment
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Summary
• Nanocellulose is in the pulp and paper making value chain considered as a high value-added product with many application in and out side of the forest products industry in thefuture
• Many different type of products with different properties are available.
• Technology and economical issues are under development to produce nanocellulose in industrial-scale amounts.
• Many studies were done to evaluate the risk potential of nanocellulose. They do not indicate any concerns.
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Acknowledgment
The research leading to these results received funding from the European Community’s Seventh Framework Programme under Grant Agreement No 228802.
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www.sunpap.vtt.fi – final conference