Plastic bags turned into high-tech nanomaterials
Researchers at the University of Adelaide have developed a process for turning plastic bags into high-tech and expensive nanomaterials called carbon nanotube membranes. Carbon nanotubes (CNTs) are tiny cylinders of carbon atoms, one nanometre in diameter, and are the strongest and stiffest materials ever discovered.
The researchers ‘grew’ CNTs onto nanoporous alumina membranes. Pieces of grocery plastic bags were vaporised in a furnace to produce carbon layers. These lined the pores in the membrane to make the CNTs. Professor Dusan Losic, of the university’s School of Chemical Engineering, said the researchers initially used ethanol to produce the nanotubes, but PhD student Tariq Altalhi conceived the idea that any carbon source should be useable.
CNTs are hundreds of times stronger than steel but six times lighter. They have a variety of valuable mechanical, electrical, thermal and transport properties which allow for potential applications including filtration, sensing, energy storage and biomedical innovations. They are already used in electronics, sports equipment, long-lasting batteries, sensing devices and wind turbines.
But the potential market for CNTs hinges on industry’s ability to produce large quantities more cheaply and uniformly; current synthesis methods usually involve complex processes and equipment which tend to produce only several grams per day. The new method is not only simplified and catalyst- and solvent-free - which means the plastic can be used without generating poisonous compounds - but the use of hexagonally arranged nanopores enables control over the nanotubes’ organisation and geometry.
Professor Losic said that as non-biodegradable plastic bags are “a serious menace to natural ecosystems and present a problem in terms of disposal … transforming these waste materials through ‘nanotechnological recycling’ provides a potential solution for minimising environmental pollution at the same time as producing high-added-value products”.
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