The new technology, developed by researchers at the Royal Institute of
Technology in Stockholm, takes ordinary cellulose and puts it through special
processing. The end result is a paper, made out of normal wood pulp that
has an incredible
tensile strength of 1.6 times that of iron. The paper sports 214 MPa
of tensile strength, easily trumping iron (130 MPa) and heavy duty paper (103
MPa). Tensile strength helps to measure how resistant a material is to
ripping, and how much weight it can support.
The new paper is composed of nano-sized whiskers of cellulose. Cellulose,
the crystalline polymer of glucose, is what makes up cell walls and makes
plants so rigid. On a nanoscale, cellulose fibers beat steel and glass in
strength, but paper is composed of larger cellulose strands that are prone to
breakage under stress. Typical commercial paper has a tensile strength of
a mere 30 MPa, indicating its weakness.
To make super paper, researchers first had to make the cellulose fibers super
small. Head researcher Lars Berglund used enzymes and mechanical beating
to tear the cellulose fibers to a mere 1,000 of their original size. Then
the researchers added carboxymethanol, which coated the fibers in carbonyl
groups. These groups produced hydrogen bonds, further strengthening the
The research was published
in the current issue of Biomacromolecules.
Mike Wolcott, a materials scientist and cellulose fiber expert at Washington
State University in Pullman, labels the paper as "quite
interesting". He notes that the paper has large pores between
fibers. These pores make it dry quicker, saving in production costs and
making manufacturing easier. John Simonsen, a physical chemist and
nanocrystalline cellulose expert at Oregon State University in Corvallis, adds
that the new material is formed from the most abundant organic material on the
planet, so even with the extra treatment it should be cost competitive against
more exotic materials like carbon nanotubes.
The new paper may be even used in medical uses such as providing scaffolds for
growing replacement tissues or organs. However its most practical
application may be as simple as the shopping bag.
quote: tensile strength is just a measure of the force required to make the material yield.
quote: after this point the tensile strength usually reduces before the the material utimately breaks apart.