New process turns wheat straw and oat husks into sustainable clothing

The grains behind some of your favourite breakfast cereals could become a part of your future wardrobe, according to new research out of Europe. 

Researchers at Chalmers University in Sweden have discovered a process to turn wheat straw and oat husks, left behind after harvest and milling, into textiles.

They hope it will eventually lead to new sources of sustainable fabric, reducing the world's reliance on synthetics made from non-renewable sources.

While farmers in Australia will need to be convinced, those working on the frontier of new materials say there are compelling reasons to explore going from high fibre to high fashion.

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The quest for new sources of textiles is not a new one. 

Before the advent of synthetics like polyester and manufactured fibres such as rayon, textiles made from cotton, wool and silk are woven through human history. 

But humanity's demand for affordable fashion is a challenge for sustainability.

The researchers at Chalmers University's department of chemistry and chemical engineering are searching for new sources of cellulose, the structural component of plant cell walls that allows them to stand upright.

Cellulose has been used in manufactured textiles since the 1880s.  

"We looked into what Sweden would have for side-streams [from farms] that contain cellulose and which would also be available for the whole year round," Associate Professor Diana Bernin, who co-authored the study, said.

Early uses of cellulose include artificial silk and carbon fibres for light bulbs, but these days it is most commonly sourced from wood and made into rayon, also known as viscose. 

Dr Bernin said the process, which involves creating a pulp similar to that used to make paper, is difficult, energy-intensive, uses toxic chemicals and has been linked to deforestation. 

Published in the Royal Society of Chemistry Sustainability journal, the study tested wheat straw, oat husks, potato and sugar beet pulp — all by-products produced on Swedish farms.

"We figured out that potato and sugar beet are very difficult because they might contain a lot of soil," Dr Bernin said. 

"But it worked very well for the oat husks and wheat straw."

Through a method called soda pulping, the plant material was able to be dissolved, washed and spun into a fibre, producing a final product "very similar" to cotton.

"Chemistry-wise, it's the same molecule inside," Dr Bernin said.

Australian potential

At Deakin University's Institute for Frontier Materials in Geelong, Associate Professor Chris Hurren is also working to reduce the environmental impact of fabric.

He said cotton made up about a quarter of the world's textile supply, wool accounted for about 2 per cent, with the remaining 65 to 70 per cent comprised of oil-based polyester.

If the oat husks and wheat straw could provide a high-purity source of cellulose then they had huge potential, he said.

"Research could occur in Australia to understand what is the ability for Australian materials to go down this path," he said.

But while the researchers were looking to add value to what European farmers considered to be waste, growers like Bradley Misfud in central Queensland already see it as valuable.

On his Kilcummin farm, south-west of Mackay, rain is sporadic and the wheat straw is "one of the biggest assets of the crop".

"Because we don't have big, strong, long winters, our wheat crops and yields aren't anywhere near what they get further south.

"We don't really have a big bulk density of straw to begin with, which is why we're pretty cautious about looking after and leaving what we have where it is."

Mr Misfud said he commonly left about 30 to 40 centimetres of wheat straw in the ground to help prevent erosion and retain soil moisture, compared to the 10-15 centimetres left behind in Sweden.

But Queensland is Australia's smallest wheat region, with the bulk of the crop grown in Western Australia, NSW, Victoria and South Australia — where, Mr Misfud said, there could be some application.

"I just feel that this particular strategy may not work in our area.

"We've all learnt with minimum till practices … capturing moisture is king, and that's what we're all trying to do day in, day out."

Beyond the climates where wheat and oats were grown, Dr Hurren said people all over the world were looking for alternative sources of cellulose.

He said seaweed, food waste, algae, banana, pineapple, kenaf, bamboo, hemp, coconut, linseed and blended textiles were all being investigated.

"We need to look at some new sources of fibres to fill the void," he said.

But he said strategies to reduce demand also needed to be explored. 

"Australia is the world leader in the number of garments we buy per person … and something like 40 per cent of the garments coming into Australia don't get sold," he said.