Hail the new golden age of wood

Ali Harlin_edit

When using wood, our forefathers were looking for the perfectly shaped branch for a handle, while spool manufacturers look for wood that is free from knots, paper manufacturers for long fibres and modern, greenhouse emission-conscious engineers are interested in biocarbon. As needs change, we can again look at trees in new ways.

Science can help us understand the structure of wood in greater depth, while technology can translate science into economic success.

Revenue from logging reserve

We have enough sustainable logging reserve to stack a six-meter high pile of logs and trunks along the tracks from Helsinki Railway Station all the way to Kemijärvi station in Lapland. In terms of firewood, the value of this pile equals a stack of 50 Euro banknotes large enough to fill the gaps between the fourteen columns of the Finnish Parliament building. But if we turn the logging residue into value-added materials, the stack could cover the entire building!

By manufacturing textiles that replace cotton, we could free up enough fields to feed 30 million people and prevent the formation of a few deserts the size of Finland.

Fibrils or crystals from cellulose walls

Identifying the cellulose cell wall structure has brought about many significant advances. In the past decade, the nano-view has revealed the fibril level of wood. Fibrils are cable-like strings that form the cellulose cell walls. While this structure was already known, the interest in the manufacture of nano-materials has driven technological development to a point where it is possible to release fibrils with reasonable energy consumption.

Fibrils allow the manufacture of completely new kinds of products and additives, such as plastic-like fine paper or very fine textile-like paper yarn. Even in small amounts, fibrils make plastics harder and more robust. Other uses include preventing paint or juice from separating, and improving the composition of concrete.

The nano-sized crystals in the fibre walls can be released by etching cellulose in a controlled manner. Capable of self-assembly, the crystals can form new materials. They scatter light and form colours. Crystalline materials can be used to improve the insulation properties and strength of different mixtures.

Recyclable textiles from wood

The swelling and dissolution of cellulose is another example of advances in green chemistry. Advanced enzymes have provided the key to a very exact method of destructuring cell walls. What is more, the advances of ionic and eutectic solvents provide a very effective and environmentally friendly way of solvating cellulose. We should consider the use of wood as a material in textile manufacturing. With the new cellulose solvents, it is possible to manufacture 100% recyclable textiles, for example.

Controlled swelling of the cell wall is an effective way of introducing chemicals into and modifying the structure. By bonding acetic acid to the cellulose structure, it is possible to create a thermoplastic material, or cellulose-based plastic. Other chemicals can improve the water-solubility of cellulose, or make cellulose more inclined to bond with other materials, enabling the use of cellulose in place of oil-based auxiliary polymers.

Converting cell walls into sugar

A third example is the use of enzymes to convert the cell wall into sugars, to produce, say, alcohol to power vehicles, without taking resources from food production. The sugars in wood allow the manufacture of molecules with a much higher value. One example is FDCA, or furandicarboxylic acid, which can be used to replace the aromatic oil-based main component in packaging and polyesters. This will also produce plastics that are stronger and have lower gas permeability than the plastics used today.

From forestry to bioeconomy and circular economy

Our forestry sector cannot be sustained by pure volume alone. New processes provide economic methods of refining wood into completely new kinds of high-value-add products. At the same time, there will be a shift in economic structures. We are moving from forestry to bioeconomy. In this context, bioeconomy refers to maximum utilisation of biomaterials in terms of utilisation rate and value. At the same time, our behaviour as consumers may shift towards a circular economy, reducing our footprint to a more sustainable level.

Investing opportunities in the new economy have created vast profits for many, but at the same time, a lot of capital remains tied to old industry, providing shrinking returns. Some companies are starting to see the light, and after a long period of non-investment have announced new investments. As Ensio Miettinen, Ensto company (Finnish company for electrical systems and supplies), founder put it:

“Today, we possess more knowledge and capital than ever before, but we need to have a firmer belief in the future.”

Utilising new technologies is always risky, but there will be no gain without risks. It is time to move onwards and upwards to a sustainable future!

 

Ali Harlin

Reasearch Professor

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