ATRIUM – Alternatives for an effective Transition to sustainable, Reusable and recyclable construction products by the Innovative production of User and eco-friendly bio-based Materials

Within the ATRIUM project, six bio-based materials are being identified and upscaled with the ambition to drive innovation in the construction sector.
This sector remains one of the world’s largest consumers of raw materials, accounting for nearly 50% of total resource use. The overarching goal is to significantly reduce the carbon footprint of buildings through the cascade utilisation of biomass and the replacement of fossil-based polymers.

As project partner and leader of Work Package 1, Wood K plus/Kompetenzzentrum Holz GmbH contributes to this transition by developing three innovative bio-based products: WPC terrace decking, bio-composite flooring tiles, and natural fibre composites for green infrastructure.

In the area of outdoor applications, Wood K plus is working on the next generation of terrace decking profiles based on sugar-cane-derived bio-PE and recycled wood dust from the furniture industry. By combining co-extrusion with a chemical foaming process, these profiles are designed to be lightweight while maintaining durability. Co-extruded structures with a foamed core and a protective outer layer offer advantages in weight reduction, cost efficiency, and sustainability while also increasing resistance to insect infestation. The development is carried out in close collaboration with Hartika, a Polish manufacturer of composite outdoor systems.

 

Detailed view on profile section (©Wood K plus)

After four series of trials, lightweight profiles with substantially reduced density (>24% under the target value) could already be produced. The foamed core layer consists of 78 wt.-% bio-LDPE and 20 wt.-% PB/MDF dust (50-500 µm). 2 wt.-% of a highly bio-based coupling agent (MAH-g-Bio-LDPE, >95% bio content) ensures strong interfacial adhesion between the fibres and the polymer. The density reduction was achieved by adding 2 wt.-% of an endothermic chemical foaming agent. For the skin layer a combination of biobased bio-HDPE and 20 wt.-% PB/MDF dust were used.

Parallel to this, Wood K plus is advancing the development of bio-based flooring carrier boards within the flooring tiles segment of the project. In close cooperation with international partners, including SQUIM, the Team „Advanced Bonding“ led by Erik van Herwijnen has developed a carbohydrate-based binder system formulated from hydroxymethylfurfural (HMF) derived from fructose and bis(hexamethylene)triamine (BHT). Combined with agricultural side streams, this system enables the production of innovative mycelium-based composite materials. Various mixtures of hemp shives, mycelium-cotton and alternative annual plants such as miscanthus are being evaluated to reduce thickness swelling focusing on standard requirements for interior flooring applications. Recent test series have not only improved the panel manufacturing process but have also reduced thickness swelling by >30% while maintaining strength properties. Nevertheless, further optimization is needed to match the demanding performance criteria of high-density flooring carrier boards.

Furthermore, Wood K plus/Kompetenzzentrum Holz is developing natural fibre composites (NFCs) based on polyhydroxyalkanoates (PHAs) for green wall systems and especially plant pots. Green walls, also known as living walls or vertical gardens, are increasingly used in modern architecture and interior design. They offer numerous benefits, including improved air quality, noise reduction, and thermal insulation, as well as providing an attractive and relaxing environment. Cooperation partners in this task are Aitiip, Tecnopackaging, and alchemia-nova.

After screening various formulations including PHA and different fibre types (hemp and softwood flour) by varying weight contents, currently two formulations with a natural fibre content of 20 wt.-% are examined in more detail and scaled up, respectively.