The next generation of latex material could be as thin as a human hair, without losing its strength, thanks to research into nanocellulose from the Australian native spinifex grass.
Working in partnership with Aboriginal traditional owners of the Camooweal region in north-west Queensland, the Indjalandji-Dhidhanu People, researchers from The University of Queensland have developed a method of extracting nanocellulose from spinifex grass.
Nanocellulose can be used as an additive in latex production, to yield a stronger and thinner membrane that is supple and flexible.
Professor Darren Martin from The University of Queensland’s Australian Institute for Bioengineering and Nanotechnology (AIBN) said the spinifex nanocellulose significantly improved the physical properties of latex, allowing the researchers to reach what he calls the “holy grail for natural rubber”.
As expected, the typical test vehicle was the latex condom.
“We tested our latex formulation on a commercial dipping line in the United States and conducted a burst test that inflates condoms and measures the volume and pressure, and on average got a performance increase of 20 percent in pressure and 40 percent in volume compared to the commercial latex control sample,” he said.
According to Professor Martin, further refinements to the engineering will yield a latex condom that is around 30 percent thinner, and will still pass all standard tests for strength and durability.
“With more process optimisation work we will be able to make devices even thinner than this,” he said.
“Late last year we were able to get down to about 45 microns on our very first commercial dipping run, which is around the width of the hair on your head.”
Latex is a multi-billion-dollar global market, and the benefits bestowed by this nanocellulose technology would be applicable for most latex manufacturers.
The emphasis on the thinness of the material is not limited to the prophylactic market - another application for latex with improved thinness and strength would be in globes.
“It would also be possible to produce latex gloves that are just as strong, but thinner, giving a more sensitive feel and less hand fatigue to users such as surgeons,” he pointed out.
“Because you would also use less latex, your material cost in production would potentially drop as well, making it even more attractive to manufacturers.”
The application of the spinifex grass is not new: it has long been used as an effective adhesive by indigenous communities in Australia, who use it to attach spear heads to wooden shafts.
In recognition of this, the University of Queensland and the Dugalunji Aboriginal Corporation have signed an agreement to recognise local Aboriginal traditional owners’ knowledge about spinifex and to ensure that they will have ongoing equity and involvement in the commercialisation of the nanocellulose technology.
Another opportunity that will arise out of this research is to establish the partners as leaders in the area of spinifex harvesting and processing, and to become a supplier of nanocellulose and other spinifex-derived products.
The commercial cultivation and process of spinifex grass could bring economic opportunities and a new industry to regional Australia and remote communities.
To convert spinifex to nanocellulose, the scientists utilise a mixture of mechanical processes and chemistry.
The grass is hedged, then chopped up and pulped with sodium hydroxide.
The mixture is then forced through a very small hole under high pressure to peel the nano-fibres apart from the pulp. The result is nanocellulose suspended in water, which can then be added to things like water-based rubber latex.