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Story | 05/17/2022 14:05:34 | 11 min Read time

Windows, roads and rubber from trees? 4 wood-based alternatives to fossils that are almost too good to be true.

Rachael Pells

Journalist

Traffic, construction and the chemical and plastics industry: the holy trinity of traditionally fossil-based sectors that seem impossible to cleanse. But who wouldn’t want to make the impossible possible? That’s why scientists are replacing unsustainable materials with brand new innovations from an ancient resource, trees. Here are four of the most exciting wood-based innovations in the pipeline.

Let’s face it – our lives depend on chemicals. And at the moment, most of them are fossil-based. There are chemicals in our laundry detergents and cosmetics, sure. But then there’s the stuff we don’t even see: the chemicals and plastics in the cars we drive and houses we build.

Petrochemicals are rapidly becoming the largest driver of global oil demand, surpassing even shipping and aviation. That must change.

Luckily, the same carbon molecules that once took mother earth millions of years to create can now be extracted from bio-based raw materials in a fraction of that time. One of the most promising ones is wood.

How do we get from fossils to wood?

By breaking down (that is, disintegrating and isolating) the particles in wood, scientists can extract specific components such as cellulose, hemicellulose and lignin – a tree’s natural binding agent.

All these components and many more can be used for commercial applications, replacing the same structures we have become reliant on in plastics and other artificial materials.

“It is exciting to learn how innovative use of biomass can give rise to materials with completely new structure-property relationships,” says Eva Malmström Jonsson, director of the Wallenberg Wood Science Center in Sweden. The entire center is dedicated to trees, its halls swarming with dozens of researchers developing new materials from and uses for one of our oldest natural resources.

“As we learn more on how to disintegrate wood and isolate its components, and subsequently how to assemble them into materials, I am positive that there will be many new innovations well-suited for existing and future applications.”

Already, there are some truly remarkable solutions taking place on a major scale. Let’s take a look.

1. Plant-protein materials inspired by spider web are game-changers in single-use plastics

Simon Hombersley remembers the moment he knew it was time to get serious about replacing plastic packaging. “My 10-year-old niece walked me out of a restaurant because there were plastic straws on the table,” he says. “I thought, my goodness, if that's the kind of consumer pressure we've got from the next generation, single-use plastics are simply not acceptable.”

Now CEO of Xampla, Hombersley leads one of the most promising startups in the biomass industry. It replaces single-use plastics traditionally found in food packaging and other everyday products with a specially-engineered protein that comes from plants.

Plant proteins have the unusual combination of being insoluble but degradable.

As scientific innovations often do, the plant-based material came about as a result of curiosity. Xampla’s academic founder, Cambridge University biophysicist professor Thomas Knowles asked himself the question: how does a spider make its silk?

Spider webs may look delicate, but they are one of the strongest materials in nature, holding up to 350 times their own weight. The magic ingredient in spider silk is protein, which is found in animals but also in plants. After learning how spiders convert their proteins, Professor Knowles set out to conduct the same process to convert plant proteins into a high performance material to replace flexible plastic film in commercial products.

"Plant proteins have the unusual combination of being insoluble but degradable, so you get something that’s high performing yet completely digestible by the creatures in marine environments,” explains Hombersley. Xampla tackles several issues with one solution. It reduces the amount of fossil-fuel plastics by offering a replacement. The use of plant-based materials, in turn, can prevent the occurrence of dangerous microplastics left in the oceans.

Unbelievable, but true:

Professor Knowles wasn’t the only one intrigued by spiders. Researchers from Finland’s Aalto University and VTT Technical Research Centre of Finland are taking this idea a step further using wood pulp: the process involves breaking down tree pulp into tiny fibres and then arranging them into a scaffold. This scaffold is then infiltrated with synthetic “spider silk” proteins developed in a lab. The result is a material that is strong enough to replace plastics in a whole range of industries including food packaging, but also medical engineering, and even aerospace.

2. A ”natural wood glue” to cut the construction industry’s massive emissions

The race is on to find bio-based solutions for chemicals like the ones found in concrete, adhesive and tarmac. Here’s why: Buildings and the construction industry – our building of roads, houses, pavements and other concrete structures in particular – were responsible for almost 40 per cent of global process-related carbon dioxide emissions in 2018.

One promising development being explored by researchers at Université Laval in Canada is the use of lignin from wood in tarmac instead of traditional bitumen, the sticky black petroleum-based substance which is mined from crude oil.

Known as the “natural wood glue”, lignin binds together the cellulose ﬁbres in plants, and it is believed it can serve the same purpose in the production of asphalt pavement. Tests are being undertaken in a high-tech simulator at Université Laval, which will assess the effect of years of heavy traffic within a short few weeks.

Using lignin in roads can benefit the planet in more ways than one. Trees are a natural source of carbon storage, as they reduce the amount of carbon dioxide floating in our atmosphere. Even after a tree has been cut, it acts as a carbon storage, so using wood materials in new places like roads keeps carbon locked up in the ground for a long time. What a way to travel, knowing you’re crossing a road that preserves something so valuable.

Unbelievable, but true:

In a preliminary study analysing the potential environmental benefits of using lignin in asphalt, results showed that emissions of up to 117,000 to 260,000 tonnes of carbon dioxide equivalent per year could be avoided in Canada alone. That is the equivalent to removing up to 56,171 cars from the road each year.

3. There’s more to sustainable traffic than fuel: fixing the rubber issue in cars

Part of the problem with our dependency of fossil-based chemicals, is that they can be found in so many of the products we use every day, without most of us even realising it. Targeting these “stealth” chemicals is a key mission for UPM researchers, as Juuso Konttinen, Vice President of UPM Biochemicals explains: “Humans have been using wood for fuel for centuries – breaking it down to the molecular level is the next step of the evolutionary pathway.”

Breaking wood down to the molecular level is the next step.

One project to have come out of UPM research is the development of Renewable Functional Fillers (RFFs), a direct replacement for the fossil-based components typically found in rubber products – for example the lining around a car door.

By breaking down the particles in hardwood – specifically, beech, which is native to Europe and relatively fast-growing – scientists can extract lignin to create a sustainable alternative to carbon black and silica. The resulting RFFs contain more than 94 per cent renewable carbon, giving them a carbon footprint that is 90 per cent lower than standard car tires.

Unbelievable, but true:

Not only are RFFs much better for the planet, they are at least 25 per cent lighter than conventional rubber fillers, too. This means that the innovation is actively influencing the way in which we can design cars and other transportation.

4. Glass from trees – and oranges? Scientists are now making transparent wood

You’d think there was a limit to stuff that can actually be replaced with wood, or at least materials based on wood. Take windows, for example: it doesn’t take a genius to realise they have to be see-through to let the light in, unlike a plank of wood.

But here, wood offers some surprises. By chemically removing lignin – the natural light-absorbing component in the tree’s cells which gives the wood its colour – researchers are able to “bleach” balsa wood until it becomes a near-transparent material.

Near-transparent wood sounds like something from the future. But there’s more. To make the wood fully transparent, researchers have previously added in plastics like acrylic. But a new experiment run by the KTH Royal Institute of Technology in Stockholm has unveiled an eco-friendly alternative from an unusual source: oranges.

Chemically adding in a natural component called limonene acrylate, made from renewable citrus, such as peel waste recycled from the orange juice industry, enabled the researchers to turn the material completely see-through. The result is a direct replacement for glass and plastic that is 100 per cent renewable.

The focus in bio-based materials has now shifted towards understanding nature’s own molecules.

This showcases a new approach to chemical woodwork altogether.

When the search for bio-based materials first started, the aim was to make exact copies of the molecular building blocks in fossil-based materials like plastics. “Now, the focus has shifted towards understanding nature's own molecules and how they can be utilized to accomplish materials with the desired properties,” Eva Malmström Jonsson of the Wallenberg Wood Science Center explains.

Unbelievable, but true:

Not only is the transparent wood material friendlier to the planet, it’s light-weight and around five times more thermally efficient. It’s also twice as strong as Plexiglass, making it ideal for use in construction. According to the KTH Royal Institute of Technology in Sweden, in the future, transparent wood could be used in, for example, smart windows and heat-storage. That future is right around the corner.

Rachael Pells is a journalist specialising in science, research and education. She has worked e.g. for WIRED UK, The Independent and Research Europe.

As everything becomes electric, renewable glycols prove their worth

Different industries are desperately trying to break up with fossil-based raw materials. Meanwhile, another major shift is taking place globally: the electrification of pretty much everything from retail to traffic.

While UPM Biochemicals offers wood-based biochemicals for replacing fossil-based materials in different applications ranging from textiles to pharmaceuticals, a major area of growth is that of renewable glycols: a natural alternative to the chemicals commonly used in applications such as antifreeze and coolants for cars.

“Electric cars depend more heavily on coolants, which means that as we shift towards electrification our reliance on coolants will increase with it,” says Juuso Konttinen, Vice President of UPM Biochemicals. He believes biochemical replacements for coolants are crucial especially when approaching climate change from a holistic point of view.

“Carbon dioxide reductions can take place in the whole journey, from fuel to materials that make the car, to the running of it as well.”

In 2023, UPM will open the world’s first bio refinery in Germany, to allow for the mass production of biochemicals including glycols. “We can make exactly the same molecules that the chemical industry is making us as of today, with no need to sacrifice the performance or the features of the product,” Konttinen says.

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