Paludi biomass originates from wet and rewetted peatlands and wet meadows. Its use as a renewable raw material combines peatland and climate protection with economic value creation: Rewetting can reduce greenhouse gas emissions and serve as an important carbon sink. At the same time, managing these areas provides biomass for innovative bio-based products such as lightweight construction materials and insulation. Its use as a raw material thus opens up new opportunities for value creation in wet and rewetted areas and can thereby contribute to peatland and climate protection.

“At Fraunhofer WKI, we investigated the suitability of wet meadow biomass as a raw material for natural fiber insulation materials. In the process, we were able to demonstrate that the lignocellulosic biomass can be processed into fibers and transformed into high-performance insulation boards and mats - similar to established wood-fiber insulation materials,” reports Dr. Julia Belda, project manager at Fraunhofer WKI.

From Wet Meadow Raw Material to Insulation Board

A particular challenge initially lay in processing the wet meadow biomass into suitable fibers. To achieve this, the biomass was thermomechanically defibrated in a refiner. Since such systems are originally designed for processing wood chips, the process control had to be specifically adapted. In this way, the researchers succeeded in producing a fibrous material suitable for the manufacture of natural fiber insulation and for use in further material development.

The fibers obtained were used to manufacture insulation panels measuring up to 1,000 × 500 × 40 mm³. Both conventional binders and thermoplastic polymer fibers are suitable as binding systems. PLA bicomponent fibers proved to be particularly promising. Due to their bio-based origin and their potential for biodegradation, they offer interesting prospects for the development of fully bio-based insulation systems.

Good Thermal Insulation and Mechanical Properties

The developed insulation materials were extensively tested. In addition to mechanical properties, the researchers analyzed, among other things, the thermal conductivity, hygroscopic behavior, and fire behavior of the materials. At a bulk density of approximately 100 kg/m³, the insulation panels achieved thermal conductivities of about 0.040 W/(m·K).

The results show that wet meadow and paludi biomass are fundamentally suitable for the production of lightweight natural fiber insulation materials. In suitable applications, they can thus replace some of the wood fibers used to date and contribute to a broader raw material base in the insulation sector.

Expanding the Use of Renewable Raw Materials

The studies highlight the potential of biomass from wet and rewet areas as an additional source of raw materials for bio-based insulation materials. Utilizing this biomass opens up new opportunities for the use of biomass resources that have previously been underutilized and contributes to a resource-efficient and more diversified supply of raw materials.

The findings provide an important foundation for further optimizing fiber processing and the insulation materials produced from it. Furthermore, they open up prospects for additional high-value applications of wetland and wet meadow biomass in the bio-based economy.