Symposium Gefahrstoffe 2012 „Schlema VII“ Nanocellulose… · Nanocellulose: Possible products...

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

D

B


D

B

NFC Production

D

B

NFC Production

D

B


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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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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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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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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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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• 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.

Symposium Gefahrstoffe 2012 „Schlema VII“ Nanocellulose… · Nanocellulose: Possible products...

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