Fraunhofer Institute for Wood Research
Wilhelm-Klauditz-Institut WKI
Fraunhofer Institute for Wood Research
Wilhelm-Klauditz-Institut WKI

Application Center for Wood Fiber Research HOFZET®

Research topic

Fiber analytics and modification

Increasing demands on the functionality, profitability and recyclability of components necessitate the development of innovative hybrid materials such as (bio) fiber composite materials. To ensure a maximum performance potential for these novel materials, the interface quality between fibers and matrix must be optimized. The optimized interface serves the effective transmission of force and ensures a high mechanical resistance in the finished component. At the “Application Center for Wood Fiber Research HOFZET”, we investigate and develop wet-chemical and physical approaches for the surface modification of fibers for the automotive, construction, astronautic and aeronautic industries.

© Fraunhofer WKI | Florian Bittner
SEM image of natural fibers on the fractured surface of a composite material

Components of a composite material, which differ considerably from one another in their chemical composition, structure and morphology, require an additional process step for the optimization of the interface quality. We develop and test methods for the (continuous) surface modification of short fibers, staple yarns, rovings and textile semi-finished products. Our research focusses hereby include pre-treatment with polyelectrolytes and adhesion promoters as well as mercerization or the application of thermoset coatings. In addition to fiber-matrix adhesion, we are also able to specifically influence and optimize the thermal, hygroscopic, optical and flame-retardant properties of fibers and composites through surface modification. Furthermore, at the HOFZET we also investigate and develop new approaches to functional integration on the basis of polyelectrolyte coatings, such as electrical or thermal conductivity.

In our cutting-edge technical center, which we operate in cooperation with the “IfBB – Institute for Bioplastics and Biocomposites“ at the Hanover University of Applied Sciences and Arts, we are able to comprehensively characterize the modified fibers. The detailed analysis of the morphological and surface chemical properties enables us to develop quality-assured, reproducible surface modification methods. We apply these methods for our customers within the framework of application-specific development contracts. In addition, we also use the methods in our independent development of functionalized (bio) hybrid materials for small and large series production. Our material development covers, amongst other things, technical (hybrid) textiles, bio-based thermoplastic-thermoset composite components and components made from (natural) fiber-reinforced plastic.

© Fraunhofer WKI | Madina Shamsuyeva
3D microscope-analysis of the wood fiber surface prior to modification
© Fraunhofer WKI | Madina Shamsuyeva
3D microscope-analysis of the wood fiber surface following modification
© Fraunhofer WKI | Madina Shamsuyeva
Measurement of the length distribution of wood fibers by means of a static image analysis system