8/10/2019 Nanocellulose films - environmentally safe alternative

1/1

Nanocellulose films

- environmentally safe alternativeJ. Vartiainen V. Kunnari T. Kaljunen T. Tammelin U. Backman M. Vikman M. Pitknen H. Kangas

VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044 VTT

Acknowledgements

The nanocellulose fil m productio n was carried out in the Naseva2 Tailoring

of Nanocellulose Structures for Industrial Applications project by the

Finnish Funding Agency for Technology and Innovation (Tekes) that is

included in the Finnish Centre for Nanocellulosic Technologies project entity

formed by UPM, VTT and Aalto University. Nanocellulose grade used was

UPM Biofibrils supplied by UPM-Kymmene.

The work was also supported by the European Commission under grant

number 247989 (NanoSustain Development of sustainable solutions f or

nano-technology-based products based on hazard characterisation and LCA).

Finally, the work was also part of Efficient Networking Towards NovelProducts and Processes (EffNet) program of Finnish Bioeconomy Cluster

FIBIC Oy. The EffNet programme has r eceived funding from Tekes the

Finnish Funding Agency for Technology and Innovation and Forestcluster

Ltd.

Nanocelluloseis one of the most promising innovations for the modern forest

sector. In the near future, nanocellulose may have a wide range

of potential application areas such as paper, packaging,

concrete, oil dri ll ing, cosmetics, feed and composite

applications. Several surveys on the toxicity of nanocellulose

have been done using well-characterized in vitro tests

commonly applied in toxicity testing protocols. The results

indicated absence of cytotoxic and genotoxic properties as well

as absence of effects on inflammatory system of nanocellulose

studied1,2, thus using nanocellulose films as packaging

materials does not pose any direct safety risks to human health

or the envir onment. H owev er, new r egulations andrecommendations regarding nanomaterials should be taken into

account when the compliance of nanocellulose film for food

contact is evaluated. At present some recommendations exists,

however, hopefully the current confusion of nanomaterials

regulations and their appliance will be clarified in the near

future3.

Film productionVTT Technical Research Centre of Finland h as developed a

semi-industrial roll-to-roll pilot-line for coating and surface

treatments of various fiber- and plastic based webs and films.

SutCo surface treatment concept includes several coating

methods, pre-treatments and curing options. SutCo-concept

was successfully utilized in production of nanocellulose films4.

Nanocellulose dispersion was carefully pre-homogenized and

then casted onto moving web using a specific feeding head. In

feeding head the nanocellulose formed an even and uniform

layer with controlled thickness. Spreading and adhesion

between the web and aqueous film forming dispersion was

carefully fixed with physical pre-activation. After drying, the film

was finally delaminated from the web and rewinded into rolls.

Film propertiesNanocellulose film was 20 m thick, strong, translucent and

easy-to-handle. Films had superb oxygen barrier properties

even at high humidity (0.8 cm3mm/m2/day; 23C, 80% RH).

Films had smooth and shiny surface, great visual appearance

and excellent printing properties. Films were also impermeable

to grease and mechanically very strong (Youngs modulus 10GPa). Plasticization with glycerin improved the processability,

but decreased the mechanical strength and barrier properties

against oxygen. Based on preliminary tests migration from

plasticized film seems to be h igher than migration from films

without plasticizer. Films degraded completely in pilot-scale

composting test (modified EN 10145) and added nanocellulose

did not decrease the degradation rate of paper. Only moisture

sensitivity and high affinity towards water may hinder the

technical applicability of nanocellulose films in the

environmentally safe packaging applications.

1) Pitknen, M., Sneck, A., Hentze, H.P., Sievnen, J., Hiltunen, J., Helln, E., Honkalampi, U., von Wright, A.Nanofibrillar cellulose Assessment of cytotoxic and genotoxic properties in vitro. Presentation in TAPPI InternationalConferenceon Nanotechnology for the ForestProducts Industry,Sep 27-29,2010, Otaniemi, Espoo, Finland.

2) Vartiainen, J., Phler, T., Sirola, K., Pylkknen, L., Alenius, H., Hokkinen, J., Tapper, U., Lahtinen, P., Kapanen, A.,Putkisto, K., Hiekkataipale, P., Eronen, P., R uokolainen, J., Laukkanen, A. 2011. Health and environmental safety

aspectsof frictiongrinding and spray drying of microfibrillatedcellulose.C ellulose18:775-786.

3) Kangas, H., Pitknen, M., S neck, A., Tanaka, A., Forsstrm, U. Assessing the characteristics and safety ofnanocellulose consensus and co-operation on national, European and international level. Presentation in 2012Tappi International Conference on Nanotechnology for Renewable Materials. June 4-7, 2012. Montreal, Quebec,

Canada.4) Tammelin,T.; Salminen, A.; Hippi, U. 2011, Patent applicationFI20116048

VTT TECHNICAL RESEARCH CENTRE OF FINLAND

www.vtt.fi