Skip to main content

Combining wood and polymers to produce a translucent, reinforced and ecological material

Periodic Reporting for period 1 - POLYWOOD (Combining wood and polymers to produce a translucent, reinforced and ecological material)

Reporting period: 2017-09-01 to 2018-08-31

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.
The deliverables were discussed between the supervisor and the associate to efficiently organise the research schedule, and meet prototyping demands in parallel. The delignification process was optimized by the team work between the innovation associate and a research engineer in chemical processes also on the team. The resin impregnation processes were optimized by team work between the innovation associate and a research technician in composites, first for thermosets, then further studies were needed for thermoplastics. We were finally able to select at least one type of thermoplastic that fit our required specifications and enable us to prototype the wood composite as desired. The protyping stage has had first conclusive results, and we were able to sell prototypes to various clients in the luxury and automotive business. We are now constantly pushing further the limits of what we can achieve. The innovation associate as well as the research technician in composites have worked hand in hand in order to produce thermoformed sheets of Woodoo composite made obtained from wood veneer. The goal is now to optimize the delignification and impregnation processes to produce Woodoo prototypes with higher thicknesses, and a dedicated project was put in place.
WOODOO’s technology has been recognized as an emergent technology with potentials worth developing and awarded with many national and international innovation Grand Prizes and received large media coverage nationwide and beyond. Translucent wood is in-line with the spreading of new bio-based alternatives, being furthermore propelled by a unique and exclusive outlook. WOODOO now has an ambitious objective to unfold the potential of this technology and make it industrially available.
The project ends now, and the expected results have been obtained and are the ones stated above: process optimization which now enables us to move to industrialization phase, identification of the best thermoplastic resin for the desired applications, hence enabling Woodoo to produce first high quality prototypes to clients in the luxury and automotive business.

The optimization of the delignification as well as the impregnation enables the process to be greener, as it consumes less chemicals and energy in general. The POLYWOOD project has thus enabled us to optimize the process hence getting us one step closer to meeting the environmental objectives stated in the first paragraph above. Furthermore, by triggering wood as raw material to deliver to the market a ready-to-use biocomposite (translucent wood) and natural side-product (lignin), WOODOO technology can be seen as a 2nd generation biorefinery. This relies on two strong features:
1. Upgrading low-grade timbers (wood from the thinning operations ...) or low-use timber (such as aspen, pine, poplar,...) bought for a very low price and then upgraded into high- or higher- added value products, making it both ecological and economical. Moderate climate native wood species performs much better towards Woodoo process than tropical woods, which are therefore not considered in its development ;
2. Selling lignin as biofuel or bio-building blocks for the chemical industry reduces the unitary production costs, in a virtuous, cradle-to-cradle process design.