Graphene, the one atom thick layer of graphite, has proven to be an exciting substance in the development of advanced materials.
Graphene sheets are formed from hexagonal carbon atoms linked by covalent bonds. Each sheet is considered as a single molecule since it is one atom thick. Graphene possesses high strength because of the strength of covalent bonds between each atom.
The electrical property of graphene is faster than any known material. Graphene has potential applications in medicine, energy, computing, and many other fields.
A recent breakthrough for graphene applications is in materials for bulletproof vests developed by combining carbon nanotubes with graphene. In 2012, researchers from the University of Wollongong (UOW) developed a new graphene-based material which is tougher than substances such as spider silk and Kevlar that are widely employed in bulletproof vests.
Ballistic/bulletproof vests employ layers of strong fibers to absorb the energy of the bullet, and deform it, to disperse its energy throughout the vests. They minimize the force of the bullet in one area, and prevent the bullet from penetrating the textile matrix and body.
Sometimes, bullets may penetrate some fiber layers of the vest. However, the energy from the bullet is absorbed by larger fiber areas as the bullet starts to deform. To this date, Kevlar and spider silk are still regarded as the toughest fibers employed in ballistic vests.
UOW researchers developed the composite material by adding equal parts of graphene and carbon nanotubes to the polymer. This graphene material was then processed into fibers using a wet-spinning method.
Could graphene replace spider silk and kevlar in bulletproof vests?
The resulting fiber was found to be exceptionally tough due to the mixture of equal parts of carbon nanotubes and graphene. According to researchers, this super tough fiber can find potential applications in bulletproof vests and advanced composite reinforcements.
The research team insist that the composite material is relatively inexpensive, and can be produced in large quantities.
Strength and toughness are two important properties of materials. The requirement of high strength and toughness is based on the applications. Ballistic applications such as bullet-proof vests require more toughness than strength, as the vest absorbs the energy of the bullet.
This research presents a novel graphene composite material that is extremely tougher than any other fibers to date. The mixture of graphene oxide particles to carbon nanotubes in solution-spun polymer creates an exceptionally strong fibrous material which finds applications not only in battlefield protection, but also in advanced materials construction.
As carbon nanotubes are capable of conducting electricity, researchers hope that this composite material can also be used in actuating materials and electrical energy storage in the future.