Nanopaper is stronger than cast iron and tougher than bone. The paper is seven times stronger and two to three times as stretchy as conventional paper
By splitting up wood pulp into cellulose nanofibers and rearranging the fibers into an entangled porous mesh, researchers have made a nanopaper that is stronger than cast iron and tougher than bone. The nanopaper is seven times stronger and two to three times as stretchy as conventional paper.
This superstrong paper could be used to make tough packaging material, filters, membranes, and even car and aircraft parts. "Wood pulp is widely available, and there is the potential to produce nanofibers in very large quantities," says Lars Berglund, a biocomposites researcher at the Royal Institute of Technology, in Stockholm, Sweden.
To make regular paper, wood chips are heated with chemicals or mechanical force to create pulp. Aggregated, 30-micrometer-thick bundles of cellulose fibers in the pulp are then intertwined to create sheets. The new nanopaper is made of much thinner 10-to-40-nanometer-thick fibers. Individual cellulose strands are very robust, Berglund says. "They have properties similar to Kevlar," he notes. Even if a sudden impact ruptures the bonds between some of the nanofibers, the defect is small enough that the entire material does not fail. The paper can withstand nearly two-thirds more force than cast iron before it breaks.
The stretchiness comes from the pores in the mesh of nanofibers. When the nanopaper is stretched, there is enough space for the fibers to slip against each other. "You can stretch it up to 10 percent before it fails," Berglund says. "Conventional paper can stretch a maximum of 3 to 4 percent, then it breaks."
Patel-Predd, Prachi, MIT Technology Review June 16, 2008
Opportunity: Strong paper could replace use on non-renewable resources
Threat: Possible threats of nano materials are not yet thoroughly researched