Australasian Science: Australia's authority on science since 1938

Spinifex Makes Condoms Thinner and Stronger

Nanocellulose extracted from spinifex grass could make condoms as thin as a human hair without any loss in strength. “The great thing about our nanocellulose is that it’s a flexible nano-additive, so we can make a stronger and thinner membrane that is supple and flexible,” said Prof Darren Martin of the Australian Institute for Bioengineering and Nanotechnology (AIBN) at The University of Queensland.

“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% in pressure and 40% in volume compared to the commercial latex control sample,” he said.

“With a little more refinement, we think we can engineer a latex condom that’s about 30% thinner, and will still pass all standards, and with more process optimisation work we will be able to make devices even thinner than this. 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.”

Martin said the benefits of the nanocellulose technology would interest latex manufacturers across the multi-billion-dollar global market. “Rather than looking at increasing the strength, companies would be looking to market the thinnest, most satisfying prophylactic possible,” he said. “Likewise, 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.

“Because you would also use less latex, your material cost in production would potentially drop as well, making it even more attractive to manufacturers.”

Martin said spinifex had long been used as an effective adhesive by indigenous communities in Australia. “Spinifex resins have been used traditionally for attaching spear heads to their wooden shafts,” he said.

The University 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.

Dr Nasim Amiralian of AIBN said the nanocellulose could be converted from spinifex using an efficient chemistry method. “You would firstly hedge the grass, and then it would be chopped up and pulped with sodium hydroxide – and at that stage it just looks like paper pulp,” she said. “Then you hit it with mechanical energy to force it through a very small hole under high pressure to peel the nanofibres apart from the pulp, into nanocellulose happily suspended in water and ready to add to things like water-based rubber latex.”