What do fridge seals, sneakers, cardboard boxes, cement and latex gloves all have in common? They can all be improved with strong and ultra-thin fibres from an Australian desert grass.

Spinifex grasses have grown in Australia for over 15 million years.

They cover nearly one-third of the continent, mostly in hot, dry areas with poor soils — and have been used for a variety of purposes by Indigenous people for thousands of years.

Indigenous people have traditionally used spinifex resin to make hafting tools ( University of Queensland: Matthew Taylor )

Some species produce a sticky resin, which Aboriginal people have used as an adhesive. But spinifex also has food, medicinal and architectural uses.

These grasses have had to adapt to changing climates, extremely poor soils, high temperature and low rainfall, which has led to their unusual structure and composition.

However, despite spinifex's abundance and unique structure, the scientific applications of this plant have been largely ignored — until recently.

In 2012, I discovered that deconstructing spinifex into its building blocks resulted in very thin, long and flexible nanofibres.

What's a nanofibre?

At nanometre scale, which is one billionth of a metre, materials' behaviour can be substantially different to what we can see with the naked eye.

Plant-derived nanofibres have unique structures and are natural, abundant, biodegradable, light and strong.

They are tens of thousands times thinner than a human hair, but five times stronger than steel.

These nanofibres are prime candidates for use as sustainable materials in industries such as packaging, automotive, aerospace, healthcare, energy, food, cosmetics and environmental health sectors that all involve petroleum-based polymers.

Spinifex grasses have adapted to Australia's harsh desert environments. ( University of Queensland: Michael Jones )

The way the spinifex desert grasses have evolved to adapt to Australia's hot and dry environment makes them an ideal source of high-quality nanofibres.

Cellulose nanofibre bundles in spinifex are organised in a loose network consisting of a soft material called hemicellulose, as opposed to the strong and tightly cemented components of wood.

This structure allows the plant to retain water during periods of drought.

The high content of hemicellulose in spinifex means the grass structure is less solid and makes isolating the nanofibres easier without using harsh chemicals and mechanical energy.

How to make grass into nanofibre

First, the grass is washed with hot water, dried and ground into a powder. Then, we isolate the nanofibres.

The grass powder is treated with a mild alkaline solution to loosen its structure before it is deconstructed using a high-pressure homogeniser, the same instrument used for homogenising milk.

These nanofibres, either in powder form or dispersed in water, are then mixed with other materials such as rubbers, latex or cardboards to improve their strength while retaining flexibility and stretchiness.

What makes spinifex nanofibres special?

Cellulose nanoparticles from cotton and wood are shorter and thicker than spinifex nanofibres. ( University of Queensland: Nasim Amiralian )

Cellulose nanofibres can be derived from trees and plants, such as wood, grass, cotton and agricultural waste. They can also come from animals, such as tunicates or 'sea squirts', and bacteria.

The drawback of many of these sources is the need to use large amounts of energy or chemicals to isolate the nanofibres, which leads to higher manufacturing costs.

In order to be able to produce cheaper and sustainable materials, we need to minimise the consumption of water, chemicals and energy.

My team and I have demonstrated that isolating nanofibre from spinifex grass needs minimal chemicals and energy compared to other sources such as wood and cotton.

Before our spinifex nanocellulose discovery, production of very long and thin spinifex-like nanofibre was limited to a marine animal called a tunicate which, due to its rarity, was limited to applications in academic reports only.

Producing high-quality nanofibre from spinifex grass using a cheaper and more environmentally friendly method is a step towards solving challenging manufacturing processing problems.

How spinifex can improve...

Cardboard and filters

The strength of cardboard decreases when it's recycled, but spinifex nanofibres can be used to strengthen the recycled product. ( Flickr: __skwrl__ )

Using spinifex nanofibre as a water filter significantly improves the removal of metal ions in water.

The hemicellulose on the surface of nanofibres works as absorption cage to trap metal ions.

Reinforcement of recycled cardboards with tough spinifex nanofibres improves its strength, which generally decreases in the recycling process.

Hemicellulose acts as an adhesive during the cardboard manufacturing process and imparts toughness and strength.

Elastomers and polymers

For stretchy, rubber-based products like gloves and condoms, we want a material that is strong and very flexible.

This combination will result in a glove or condom that is resistant to breakage, but also allows for a close fit and improved sensation.

The common reinforcing agents used in rubbers to improve their mechanical properties are silica, carbon black, carbon nanotubes and graphene.

These can provide strength but, due to their rigidity, can also make the material too stiff or less stretchy.

A solution to this is using a soft and tough filler — such as spinifex nanofibres — to produce a thinner, tactile membrane.

In other rubber applications, such as seals, tyres and boots, similar technical requirements exist.

For all of these, we are looking for toughness and abrasion resistance while still retaining the soft, elastic nature of rubber.

Adding just a small amount of spinifex nanofibres into different types of rubber results in a significant improvement in the strength of rubbers without reduction of their resilience and flexibility.

Concrete

About three tonnes of cement-based building materials are used per capita in the world each year.

The demand for building materials globally is expected to increase by 7 per cent by 2021 for developing buildings and infrastructure for the world's growing population.

This means a lot of cement, which in turn means lots of energy consumption and carbon emissions.

Spinifex nanofibre has shown to increase the strength of cement by at least 20 per cent. This means that we can reduce the amount of cement needed or we can make thinner structures.

We're still working on perfecting how to improve these products with spinifex nanofibres, but expect to start seeing them in the world around you within three to five years.

Dr Nasim Amiralian is a nanomaterials engineer at Australian Institute for Bioengineering and Nanotechnology, University of Queensland. She is also one of the ABC's Top 5 scientists for 2018.