Lignin helps the biobased economy move forward
After cellulose, lignin is the most common organic aromatic material on earth. Trees, grasses and straw derive their firmness and flexibility from this natural adhesive. At Wageningen University & Research, we are convinced that lignin can help the biobased economy make a great step forward. Due to its natural properties, the material is suitable for a wide variety of biobased applications. We are developing these applications together with governments and industry.
A fine example of how we have quickly succeeded in taking the step from the lab to a practical application is the use of lignin as a replacement for bitumen in asphalt. Bitumen is the tar-like residue which remains after petroleum refining. In the Bioasfalt Zeeland project we developed a technological process which gave lignin the same properties as bitumen. An added benefit is that bio-asphalt can be applied at 30 degrees Celsius lower temperature compared to conventional asphalt. In addition to replacing fossil resources it therefore has the added benefit of considerable CO2 savings.
70 metres of bio-asphalt
A test surface of 70 metres of bio-asphalt was laid in f Sas van Gent in the Dutch province of Zeeland in July 2015 on a stretch of road with a lot of heavy (truck) traffic. Currently, we have not seen any difference to conventional asphalt. Now it is a matter of waiting for a harsh winter to test the quality and stability of the bio-asphalt in extreme conditions. If the test results remain positive, we will be making a substantial step towards more sustainable roads.
Lignin as replacement for phenol and formaldehyde
Another promising option is the replacement of synthetic adhesives such as phenol and formaldehyde. The industry and companies such as IKEA wish to stop using these expensive and toxic substances and hope that lignin will offer the solution. In recent years we have been involved, among other things, in developing a technology to process lignin in such a way that the material has exactly the same properties as its synthetic counterparts. And we have made good progress. For instance, there is already a multiplex product on the market in which 30% of the phenol has been replaced by lignin. In the lab we have achieved a 75% replacement.
Lignin in PUR foam
Where the above examples describe the replacement of existing properties, we are also active in other projects in which we use lignin to improve functionalities. A good example is PUR foam, which traditionally consists of the elements polyol and urethane. Although there are already biobased polyols on the market, we are working on formulas to replace the substance by lignin. We expect that this will allow us to make PUR foam that offers even greater fire retardancy and has even better stabilising and insulating properties.
The interest in lignin from the industry is undiminished. Although there are still plenty of challenges to face on the road to successful market introductions, the potential of lignin is excellent. The green gold of the biobased economy? I believe so. Please share your view in the comment section below.
Join the congress The Future of Aromatics 2016 on 13-14 January in Amsterdam to view my presentation ‘Lignin: a source for bioaromatics’.