A great challenge for humankind is to progress towards a sustainable society. Such a society will require the use of renewable materials, coupled with large reductions in the overall use of natural resources and in environmental impacts including greenhouse gas (GHG) emissions. The building environment is a key sector in meeting this challenge, due to its large use of natural resources and primary energy and its significant impacts on the environment. In Europe, the building environment accounts for about 42% of energy use and produces 35% of total GHG emissions . Wood is an inherently renewable material that is produced through natural processes in forest ecosystems. Manufacturing wood products typically requires less total energy, and in particular less fossil energy, than the manufacturing of most alternative materials. Cradle-to-gate analyses of material production, including the acquisition of raw materials (e.g. mining or forest management), transport, and processing into usable products, show that wood products need less production energy than a functionally equivalent amount of metals, concrete or bricks.
However, wood utilisation declines over the years as it has four strong limitations: it burns, it rots, it has a limited structural resistance and durability, and it is opaque. However, wood covers 40% of the EU land and has a natural increase rate of 0.4% per year, hence a large potential to reveal. Wood has a crucial role to play in the years to come as it is the only renewable building material which grows on its own, able to store CO2 (1 ton of CO2/m3 of wood) unlike most man-made materials, and widely available locally, and throughout the EU.
WOODOO has developed a breakthrough technology (patented process B150222FRA), based on the structural modification of wood at the cellular and molecular scales, to overcome all these major limitations while ensuring a sustainable built environment based on resource-efficient systems with low environmental impact. The process consists in removing lignin from native wood and then filling the cellulosic matrix with bio-based polymers. By polymerizing in- situ, much stronger bonds between wood fibers are created, improving native wood’s mechanical performance, while keeping competitive environmental performance and enhancing its resistance to decay (fire, fungi, insects), as well as making it translucent. Despite its slightly higher use of fossil energy compared to bulk wood products, WOODOO energy consumption process remains highly attractive compared to non-wood building materials. The resulting translucent wood is as stiff as concrete but with a carbon footprint 3 times lower.
In the frame of EASME Horizon 2020, the project POLYWOOD is to develop wood composite where the structural integrity of the wood is retained, which confer novel properties to the wood such as increase wood stiffness and wood resistance to decay. The first step of the process of translucent wood is the delignification. The lignin removal is important for the optical properties of the wood composite. The free volume created between the fibres will allow to improve the interface between the cellulose fibrils and the polymer matrix. Two major families of polymers can be distinguished: thermoset and thermoplastic.
Three objectives were defined for the POLYWOOD project, and the associate: 1) optimize the delignification process, 2) identify polymers that would meet the specifications for the impregnation stage, and optimize its processing into the delignified wood, 3) contribute to prototyping for clients.
