BRISBANE, Australia—Australian native spinifex grass fibers could be used to make paper to replace some plastics packaging—and thinner condoms.
The grass, which grows in semi-arid regions in Australia, has a stretchy polymer in its cell walls that protects the plant in hot weather.
Professor Darren Martin at the Australian Institute of Bioengineering and Nanotechnology, a specialist unit of the Brisbane-based University of Queensland, has broken spinifex leaves down to extract nanocellulose that can be added to a range of products to improve their strength, toughness and flexibility.
One potential application is paper that can be stretched like thermoplastic, providing the potential for biodegradable paper packaging.
"Our toughest spinifex 'nanopaper' has even better stretchiness and formability than ABS polymer. We're pretty excited about that," Martin said. "Wouldn't it be cool to replace … thermoplastic packaging with 100 percent sustainable and biodegradable paper packaging?"
Martin is seeking grant funding to further develop the research, which he says also offers the possibility of stiffer, stronger, more water-resistant cardboard.
He is also collaborating with scientists at Melbourne's Deakin University to add the nanofibers to polyacrylonitrile used to make carbon fiber. "It's at the fundamental, basic science level at the moment."
However, Martin said there is potential for saving energy by producing carbon fiber at lower temperatures.
Martin's research has also seen spinifex grass nanofibers added to latex to manufacture thinner condoms. Commercial trials have been successful in the United States and Asia. Manufacturers have tested products made on their dipping lines, where glass molds are dipped into latex as the initial step in manufacturing condoms.
Martin said the nanofiber products must "tick a lot of boxes before we can scale up and go into commercial production."
Condoms must demonstrate the ability to sustain pressure of at least one kilopascal and have 18 liters of air blown into them before they burst.
"The holy grail is a latex condom of less than 35 microns. If all the ultrathin samples pass the burst test, and the additive is easy to incorporate, we will be in a very happy place."
Martin said the nanofiber additive is non-toxic and makes latex softer so films are more supple and flexible.
Spinifex grass used in the research has been obtained through a partnership with Aboriginal traditional owners in far northwest Queensland.
Indigenous Australians have long used spinifex as an effective adhesive.
"Spinifex resins have been used traditionally for attaching spear heads to their wooden shafts," Martin said. While studying the resin, his research team realized the potential for using the leaves' cellular properties.
Martin's earlier research has involved commercializing plastics additives to create tougher acrylic glass; and developing nanocomposite thermoplastic polyurethanes with applications ranging from biomedical devices and industrial components to sports footwear and golf balls.
The University of Queensland formed a spin-off company, TenasiTech Pty. Ltd., to commercialize Martin's patented process of adding synthetic nanoparticles to conventional TPU to improve the material's performance drastically.