SusSand - Sustainable sandwich material with total substitution of fossil-based components with forestry residues

Important results from the project

To produce a sandwich panel today, fossil-based raw materials such as extruded polystyrene foam as insulation core material, and polyester-based outer panels with energy-intensive glass fibers as reinforcement are used. By producing a sandwich panel entirely from biobased raw materials and residual streams from pulp production, the environmental footprint would be significantly reduced. The feasibility of this has been investigated by manufacturing a cellulose-based foam as insulation core material and lignin-based outer panels with biobased reinforcing fibers.

Expected long term effects

The project has successfully produced variants of a sandwich composite from biobased raw materials. The insulating properties are at least in par with the reference materials. There is room for improvement in the mechanical properties, primarily in tensile and impact strength. The results provide good indications that necessary strength can be achieved through recipe optimization and alternative biobased reinforcing materials in the panel matrix. The positive results are expected to generate significant interest among stakeholders in the sandwich panel value chain.

Approach and implementation

To produce demonstrators of fully bio-based sandwich panels, several cellulose-based insulation foams have been developed with a focus on different properties, such as insulation capacity, strength, and fire resistance. The lignin-based panels have been manufactured separately and then glued onto the foam to form a complete sandwich composite. The separate components underwent mechanical tests before the mechanical properties of the sandwich panel were determined using standardized methods. The results were then compared to data from currently available sandwich panels.