Posted: September 14, 2009

Indian scientists develop world's hardest nanocomposite material

(Nanowerk News) The world's hardest plastic nano-composite material that can be used in missiles and aeroplanes has been discovered by a team of five Bangalore researchers headed by CNR Rao, scientific advisor to the Prime Minister of India.
They created the material by reinforcing ordinary plastic with nano-diamonds, a sheet of layered carbon and tiny carbon cylinders.
For the reinforcement they used materials of nano-dimension. Strengthening a common polymer with nano-diamond, a new age material called graphene (one atom thick carbon honeycomb sheet) and carbon nanotubes has produced this material with extra hardness and stiffness.
"The mechanical properties like hardness and stiffness (after moulding) improved by as much as 400 per cent compared to those obtained with single reinforcements," the researchers reported in the Proceedings of National Academy of Sciences. The team comprises researchers from Indian Institute of Science and Jawaharlal Nehru Centre for Advanced Scientific Research. The original idea came from Rao - an eminent scientist and founding president of the JNCASR.
Upadrasta Rammurthy, a professor of material engineering at IISc and one of the team members said that despite its hardness the material is extremely light-weight. "It can be used in missile and aerospace engineering. However, we have not yet looked into the application side," he said. While scientists do use nano-materials as reinforcing agents, the Bangalore team has adopted a new strategy by using a combination two nano-materials. The polymer they chose is polyvinyl alcohol.
Winning combinations
They hit upon two winning combinations - graphene and nano-diamond; and carbon nano tubes and nano-diamond. Both combinations result into development of "high-performance polymer matrix composite." High performance comes from the synergy between polymer and nano-materials.
"The synergy shows one plus one can become eleven also and need not necessarily be two always," Ramamurthy said quoting a phrase often used by Rao.
Despite being the world's hardest plastic nano-composite, the reinforcement material constitutes only one per cent (by weight) of the composite. To create a similar material conventionally, 50-60 per cent glass was required as the reinforcing agent and the resultant composite could not be moulded. Besides excellent mechanical properties, the reinforced polymer also shows semi-conducting behaviour, which could also be exploited.
However, researchers are yet to analyse the new material's toughness and ductility, without which the extent of practical application could not be decided.
Source: Jawaharlal Nehru Centre for Advanced Scientific Research
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