CIRCULAR ECONOMIES AND SUSTAINABLE FUTURES:

BIOWASTE AS RENEWABLE ENERGY AND ECOFIBRES

The ecofibre breakthrough required guts and collaboration, says Herbert Sixta

When the decline of the paper industry steepened, researchers started to develop new bioproducts. Ioncell, based on pulp and textile waste, is a forerunner in recyclable biofibres.

Ioncell became known to the general public when Finland's First Lady Jenni Haukio dressed in an evening gown made from birch for the Independence Day reception in 2018.

Ioncell is a method that turns pulp, recycled paper and cardboard, and textile waste into high-quality textile fibres. But first and foremost, Ioncell is a scientific research project uniting experts from different fields.

When Aalto University Professor Herbert Sixta came to Finland in 2007, the time was ripe for new bioproducts. The paper industry was in a deep recession and factories were being shut down. Looking for something to replace declining paper production, many universities and businesses took part  in a mega project funded by the Finnish Funding Agency for Technology and Innovation Tekes, a predecessor of Business Finland.

Pulp has long been turned into viscose fibres, but the production process uses toxic chemicals and is unsustainable, and manufacturing has largely moved to Asia. New, environmentally friendly fibres could help bring the industry back to Europe.

Sixta had worked for 30 years in a textile and pulp firm in Austria. It was therefore natural for him to go into the development of bio-based textile fibres and their manufacturing process. Helsinki University Professor Ilkka Kilpeläinen had previously studied the dissolution of cellulose. He and Sixta started to develop a process for manufacturing fibre.

‘The biggest challenge was finding a suitable solvent,’ says Sixta. ‘The dissolution of cellulose is not efficient enough for spinning filaments from the raw material. Spinning is a mechanical process and requires the raw material to be stretched to achieve tensile strength. In the process, the molecules are pulled into alignment, making the filaments strong.’

Aalto's strength

After two years of trial and error, a breakthrough came in 2013. The researchers managed to produce strong filaments using a dry jet-wet spinning method. The solvents used are ionic liquids, which are liquid salts. Ioncell produces lyocell textiles, but it is more stable than earlier lyocell production methods and doesn't require other chemicals besides ionic liquids.

Marimekko exhibited an Ioncell garment in its March 2014 fashion show at the Central Railway Station in Helsinki. In 2016, Ioncell won the H&M Global Change Award. A startup company to begin commercialising the method will launch operations this year. The pilot factory will aim to develop a profitable closed-loop production process.

Ioncell has been a forerunner in bio-based, recyclable textile fibres. For Sixta, the most rewarding aspect has been the interdisciplinary collaborations, for example between chemists and fashion designers.

‘When Aalto University first started, people wondered whether it was sensible to bring technical sciences and arts under the same roof. In the end, that turned out to be Aalto's strength,’ he says.

Text by Terhi Hautamäki

Jaana Vapaavuori: Biowaste also works with solar cells

Functional biomaterials can be used in future energy production and smart textiles. Agricultural and industrial biowaste can already be utilised in an astonishing variety of applications in laboratory conditions.

Solar cells produce clean energy, but the raw materials and manufacturing processes behind them can be environmentally harmful. For example, the cells require transparent, electrically conductive glass plates, and their production consumes a lot of energy.

Researchers at Aalto University are developing solar cells which replace the glass with a transparent, flexible film made plant biomass, such as lignocellulose. ‘Biomaterials allow for a significantly more energy efficient production process,’ says Jaana Vapaavuori, assistant professor of functional materials at the Aalto University.

Vapaavuori heads a research group focusing on multifunctional materials. By deconstructing and reassembling plant biomass, it can be turned into materials that can capture and direct light appropriately for optical applications.

Each application could require different optical properties, such as transparency, reflectiveness or UV light filtering. Bio-based solar cells, optic fibres and smart textiles utilising solar energy are examples of potential applications. Since biomaterials can easily be made flexible, they’re suitable for various use in films with high mechanical resistance and wearable electronics.

The desired functional properties are mainly achieved by modifying the components of the raw material. ‘For example, we’ve compressed the network-like structures of cellulose to a single level and produced thin films for optical applications,’ Vapaavuori says.

Profitable and sustainable

The bio-based applications are still at the basic research and prototyping stage. Scientists at Aalto University are also looking into sourcing new raw materials in a sustainable manner. Chopping down forests isn’t a sensible approach for all applications. Trees grow slowly, and there's a large market for wood in the paper, packaging and furniture industries.  

According to Vapaavuori, side streams from the food industry and food processing are particularly important sources of raw materials. Last year, she and her research group manufactured a supercapacitor with fast energy storage purely from biomaterials. ‘The electrolyte came from beer brewery waste and electrodes from slaughterhouse waste,’ she says.

Using biomass in functional applications is becoming financially feasible. As waste regulations tighten, businesses have more incentives to make use of their side streams.

Biomass has the potential to replace nearly all nonrenewable raw materials. Vapaavuori is particularly inspired by the moments when an idea materialises and something new becomes possible. ‘Ideas arise from conversations with colleagues. We often toss around suggestions: maybe we could produce an edible solar cell.’

That idea hasn't materialised, yet, but it's not impossible.

Text by Terhi Hautamäki