Nanotechnology + Renewable Materials = Opportunity
By Colleen Walker

(Editor's Note: This article originally appeared in the November 2013 Nano Pages section of Coating International Magazine.)

The combination of nanotechnology and renewable materials offers a potentially significant commercial opportunity for the forest products industry.

While the promise of this opportunity has been brewing for a number of years, there was renewed excitement at the 2013 TAPPI International Conference on Nanotechnology for Renewable Materials held this past June in Stockholm, Sweden.

Co-chaired by Ulla Forsström (VTT), Phil Jones (IMERYS), and Bruce Lyne (KTH), more than 270 delegates from 28 countries gathered to hear the latest advances in characterization, chemistry, applications and processing issues related to cellulose and other bionanomaterials.

With more than 26 paper companies from around the world represented, along with 31 chemical and technology suppliers, fulfillment of the promise of new products, applications, and technology breakthroughs could be just around the corner.

THE PATH TO COMMERCIALIZATION
Four keynote speakers at the conference focused on challenges related to commercializing cellulose nanomaterials. Dr. David Lazarevic, a researcher with KTH's Division of Environmental Strategies Research and the Division of Industrial Ecology, gave the opening keynote address, and focused on the value and importance of using life cycle assessments as tools for evaluating the environmental impacts of renewable nanomaterials versus non-renewable nanomaterials. Continuing on the theme of safe use and handling of nanomaterials, Dr. Jukka Ahtiainen, a Senior Researcher with the Finnish Safety and Chemicals Agency, discussed regulatory tools under exploration for ensuring the safety of nanomaterials.

Katja Salmenkivi, Principal, Pöyry Management Consulting, presented recent trends in patents on cellulose nanomaterials and the players active the field. Salmenkivi revealed that a recent Pöyry analysis found that patents issued for cellulose nanomaterials have doubled over the last two years; most was related to production of the nanomaterials while the number of patents for applications remained constant. Applications patents cover a wide range, with composites and paper coating accounting for the greatest percentage.

Martha Marrapese, Partner with Keller & Heckman, provided her ten key considerations for successful technology transfer for cellulose nanomaterials including: time and cost to commercialize, the complimentary roles of government and industry, exploring higher-value product lines en route to entering larger, lower-margin markets, understanding regulatory hurdles, and more. Marrapese's presentation underscored the many scientific, economic, and regulatory considerations needed to move nanomaterials into the commercial marketplace.

BARRIERS & COATINGS
The conference featured several sessions that focused on using cellulose and renewable nanomaterials to improve barriers and coatings, as well as new coating technologies. Substrates and treated surface applications ranged from traditional paper grades and polymer films to cellulose-based films and composites. A few examples of work being done with barrier coatings follow.

Current approaches involve incorporating either cellulosic or inorganic nanomaterials directly into the furnish, or pre-mixing or reacting these nanomaterials with the fillers or other components. Tiemo Arndt at the Papiertechnische Stiftung (Germany), showed that the addition of cellulose nanomaterials can improve the flocculation of both precipitated calcium carbonate (PCC) and kaolin. Katariina Torvinen at VTT (Finland), shared their latest research on using nanoscale calcium silicate hydrate to introduce nanoparticles to the surface of coating fillers.

Cellulose nanomaterials can be formed into films with excellent optical transmittance and low surface roughness. This smooth surface, as compared to traditional paper, provides a good base for printed electronics. Organic filled-effect transistors have been successfully printed on films made from cellulose nanomaterials. Céline Guézénnec with The International School of Paper, Print Media and Biomaterials and the Centre Technique du Papier (France), presented work on using sorbitol in nanocellulose films to improve barrier properties. Christian Aulin with Innventia (Sweden), presented how vermiculite can be used to improve barrier properties in nanocellulose films.

COMPOSITES FROM RENEWABLE MATERIALS
As in years past, several sessions explored the use of cellulose and renewable nanomaterials for use in composite materials for a wide range of applications. Dr. Dylan Boday of IBM (USA), returned to give an update on their work. In 2010, IBM launched a Renewable Materials Initiative to replace petroleum-based products for information technology product applications. This initiative was directed at establishing a roadmap for a sustainable product line, and qualifying new renewable materials. While IBM is exploring many options for incorporating renewable materials, Dylan reported on the fire retardant properties of films made from cellulose nanomaterials.

Dr. Shaul Lapidot from Melodea (Israel), also returned to the Nano Conference to give an update on their use of waste streams from pulp and paper mills to produce renewable foams. Melodea isolates cellulose nanocrystals from the waste streams and produces foams for core materials in sandwich composites. Their latest work incorporates furan resins to obtain increases in strength and fire retardation properties.

Cellulose nanomaterials are also being investigated for use in cements. Jeffrey Youngblood with Purdue University (USA), presented his work, finding that the incorporation of cellulose nanocrystals into cement can increase the flexural strength, acting as a super plasticizer and stabilizer of cement particles.

NOVEL APPLICATIONS
For the first time, the Nano Conference featured an entire session devoted to cellulose and renewable nanomaterials being used in medical applications. Dr. Ilari Filpponen from Aalto University (Finland), presented work on immobilizing antibodies on cellulose films for use as a diagnostic tool. Dr. David Plackett with the University of British Columbia's Pharmaceutical Sciences (Canada) presented their latest investigations into the binding and release of specific drugs using cellulose nanomaterials as a substrate.

Dr. Orlando Rojas from North Carolina State University (USA), presented his research team's findings on using nanofibrillated cellulose as a carrier for short peptides assemblies for detection and affinity separation of human gamma globulin (IgG); their system could detect IgG at concentrations as low as 0.05 mg/mL. Dr. Yuvraj Singh Negi from the Indian Institute of Technology Roorkee, presented work on using xylan- or cellulose-based nanoparticle carriers for ester prodrugs (Note: A prodrug is a medication that is administered in an inactive or less than fully active form and converted to its active form through normal body metabolic processes.)

HONORING A PIONEER AT THE VASA MUESUM
Professor Derek Gray of McGill University (Canada), was awarded the 2013 Marcus Wallenberg Prize, presented to an individual to recognize, encourage and stimulate path breaking scientific achievements which contribute significantly to broadening knowledge and to technical development within fields of importance to forestry and forest industries. Standing close to the Vasa, a 333-year old wooden ship-and a Stockholm treasure-Professor Gray gave a brief presentation to the 2013 Nano Conference attendees on the history of nanocellulose, highlighting key publications, important properties, and scaling up of production.

POSTER PRESENTERS HONORED
The Student Poster Competition provides an opportunity for students to be recognized for their research efforts. This year's competition and cash prize was sponsored by Verso Paper Corp (USA), and reviewed by a team of judges who evaluated the objective of the work, experimental plan, layout and presentation of results and conclusions.

First Place was awarded to Christina Schütz from the Wallenberg Wood Science Center, Royal Institute of Technology and Department of Materials and Environmental Chemistry, Stockholm University (Sweden), for her poster "Carbon Aerogels from Bacterial Nanocellulose as Anodes for Lithium Ion Battery."

Second Place was awarded to Virginie Bigand from Grenoble INP Pagora - LGP2 (France), for her poster "Use of Different Quality of MFC for Producing Controlled Release Films." And third place prize went to Assya Boujemaoui from KTH Royal Institute of Technology (Sweden), for "Nanostructured Biocomposite Materials of poly-e-caprolactone and High Surface Area Nanopaper."

STANDARDS WORKSHOP
For the third year, participants gathered to discuss and coordinate standards development to support the commercial use of cellulose nanomaterials. TAPPI's International Nanotechnology Standards Coordination Committee (INSCC) hosted a series of working sessions to facilitate cooperation and knowledge sharing. The primary role of the INSCC is to facilitate communication among the many standards-developing organizations, and to coordinate efforts.

An update on the TAPPI Standard on Terminology was presented, which is currently out for balloting. Updates were also provided on activities in the International Organization for Standardization ISO TC 229 and ISO TC 6 communities. The Canadian Standards Association (CSA) also gave an update on their efforts to develop a national standard for Canada.

In a concurrent session, experts interested in the development of Environment, Health & Safety standards met to discuss their work to date. Efforts are ongoing in collecting sample protocols, identifying existing standards that may be applicable, and identifying priorities for standards development. The group agreed that the most immediate need is for standardized methods to measure nanocellulose in the air in a workplace. If you are interested in joining this working group, please contact Jo Anne Shatkin at jashatkin@gmail.com.

IMPORTANT NOTE: Presentations from the 2013 Conference are now available for download free to TAPPI members. Visit www.tappi.org and search on Nanotechnology 2013.

Colleen Walker, Ph.D., is Project Manager and Technical Lead, TAPPI, and can be contacted at cwalker@tappi.org.

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