Biomedical Engineering Reference
In-Depth Information
(2) optical properties and (3) surface enhancement. It was envisioned that nanotech-
nology could generate these breakthroughs where conventional approaches have been
lacking. These enabling and precompetitive technology breakthroughs in the three key
areas can then be leveraged separately or in combination by the industry to generate
competitive advantage. The solutions would allow radical reduction of raw material
use by the industry and its customers; provide opportunities to develop and market new
and advanced products with superior performance; and ultimately allow the industry
to develop new and unique materials for markets outside the pulp and paper industry.
Reduced grammage (basis weight) of paper and paperboard products will substantially
reduce wood consumption and the volume of material processed in the pulp and paper
industry, with proportional energy reductions and environmental impact. It will also
reduce the mass of nonrecoverable paper ending up in landfills. Furthermore, it would
provide opportunities to replace nonrenewable materials in a wide range of markets
with sustainable materials made from cellulose-based alternatives. The physical and
chemical properties of the cellulose fiber network in paper and board have been studied
extensively over the past 50 years and vast amounts of information on the subject can
be found in the literature. In essence the strength of the network is governed by the
bond strength, fiber strength, fiber size and shape, effect of any additives or fillers and
uniformity of material distribution. While commercial strength enhancement chemicals
are effective to a point, these technologies are not capable of leveraging the inherent
strength of cellulose nanofibrillar material, which approaches that of steel. In addition
many biologically derived materials of high strength are made up of building blocks that
are noncovalently bonded. They rely on the shear large number of points of contact to
build strength and provide mechanisms for energy dissipation, i.e. crack termination.
Therefore, it is an opportunity in using nanotechnology to diminish or close the gap
between actual current network strength, and the orders of magnitude higher strength of
the basic cellulose structure building blocks. Both nature and science have accomplished
some impressive results in strength development using very small amounts of materials
on the nanoscale.
As part of previous research in this area, extensive modeling and theoretical back-
ground results have been accomplished, and it is likely that this information can be
used as a starting point for developing the theoretical foundation for a nanotechnology-
derived strength enhancement. There is a need as part of this priority area to develop
tailored modeling capabilities and theory to predict and elucidate strength effects of
nanoscale-level modifications to the network structure and effects of nanodimensionally
sized additives. This enhanced modeling package should be used as part of a first step to
develop a theoretical perspective on the levels and kinds of enhancements to the struc-
ture that will be needed to meet research objectives. Such nanotechnology solutions will
allow a 40% reduction of basis weight of current products and establish the precompeti-
tive platform for development of new and stronger materials from cellulosic fibers. The
preferred solution will allow the industry to continue using current production assets,
but this should not be a constraint on the development work. There is a great deal of
value in solutions that involve significant modifications to infrastructure as well. Those
solutions that allow significant simplifications of the current assets are of special inter-
est. Data are readily available in the literature to understand what the property effects
of reduced basis weights will be with the limitations of current technology. It is known
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