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February 03, 2012

Bullet Proof Polymer with equal parts graphene and carbon nanotubes tougher than Kevlar

University of Wollongong researchers have used graphene to develop a new composite material which can produce the toughest fibres to date- even tougher than spider silk and Kevlar!

Graphene, the latest discovery in the nano world of carbon, has proven to be an amazing building block for advanced materials. The new graphene composite can be wet-spun into fibres with potential applications in bullet-proof vests and reinforcements for advanced composite materials.

As published today in Nature Communications, researchers from the UOW-based Centre of Excellence for Electromaterials Science (ACES) have shown that graphene can work just as carbon nanotubes, a more common toughening agent, in polymer composites. It is also a much cheaper material and can be produced easily in large quantities.

“Quite surprisingly, we found that a ‘magic mixture’ of equal parts carbon nanotubes and graphene added to the polymer gave exceptionally high toughness,” he said.

“Fibres made from other combinations of these materials were not especially tough at all.”

Professor Spinks explained that the super tough fibres can be produced easily by a wet-spinning method and can be readily up-scaled. In this case, fibres were spun by collaborators at the Centre for Bio-Artificial Muscle at Hanyang University, Korea.


Nature Communications - Synergistic toughening of composite fibres by self-alignment of reduced graphene oxide and carbon nanotubes




The extraordinary properties of graphene and carbon nanotubes motivate the development of methods for their use in producing continuous, strong, tough fibres. Previous work has shown that the toughness of the carbon nanotube-reinforced polymer fibres exceeds that of previously known materials. Here we show that further increased toughness results from combining carbon nanotubes and reduced graphene oxide flakes in solution-spun polymer fibres. The gravimetric toughness approaches 1,000 J g−1, far exceeding spider dragline silk (165 J g−1) and Kevlar (78 J g−1). This toughness enhancement is consistent with the observed formation of an interconnected network of partially aligned reduced graphene oxide flakes and carbon nanotubes during solution spinning, which act to deflect cracks and allow energy-consuming polymer deformation. Toughness is sensitive to the volume ratio of the reduced graphene oxide flakes to the carbon nanotubes in the spinning solution and the degree of graphene oxidation. The hybrid fibres were sewable and weavable, and could be shaped into high-modulus helical springs.
Preparation and structure of polymer composite fibres. Sonication and subsequent wet spinning.

8 pages of supplemental material

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