Lignin – A resource with great potential for sustainable applications
Lignin is an organic substance binding cellulose and hemicellulose in all plants. After cellulose, it is the second most abundant biopolymer on earth. Lignin is a 3D complex molecule built up from phenolic alcohols, known as nature’s glue. About 100 million tons are produced worldwide as by-product of wood pulping mills and biorefinery set-ups. There are two principal categories of lignin: sulphur-containing and sulphur-free.
Over the last decades there has been a growing demand for using renewable and biodegradable materials in the polymer market. Therefore, the research on bio-based materials contributing to a competitive economy has become one rising activity. Annual publication overview indicates that the number of papers published on lignin has increased from 1000 to 3500 over the last twenty years. This significant rate shows the enormous demand for lignin-based products in near future.
While lignin as a component in thermoplastic polymers has emerged as a promising approach for its value-added utilization, replacement of fossil-based phenol with bio-based lignin has become one of the hot topics in phenol-formaldehyde resin industries. Plywood production using lignin-based phenolic resin is one of that highly focused research. Other composite examples are laminated veneer lumber, glue laminated timber, paper-based laminates, and mineral-based insulation boards.
There are other areas in which lignin is applicable, for instance Asphalt, Carbon fibre, Foam, Coating & Paints, 3D Printing, Battey, Hydrogel, Fertiliser, Ceramic, Cement, Cosmetics, Supplementary materials, and some other applications under study. Limited fossil-based sources and CO2 emission concern are main driving force to move toward bio-based industries.