Roman Rinberg

New Biocomposites for Lightweight Structures and their Processes

The development of new biocomposites and efficient manufacturing methods that are suitable for series processing is the purpose of the current sub-project C4 of the Excellence Cluster MERGE, sponsored by DFG (Deutsche Forschungsgemeinschaft). Two different types of materials are combined: bio-based thermoplastic polymers such as bio-polyethylenes or bio-polyamides and renewable reinforcing materials such as thin wood veneer or unidirectional flax fibers. To achieve a high-efficiency in terms of mass-production, reproducibility and flexibility, it is required to perform several steps in the realization of semi-finished and final products. The improvement of the adhesion at the interface of the components, the implementation of continuous processes, in order to increase energetically the yielding, and the final design, through several methods, for future potential applications are so many perspectives to achieve.

Processing of Wet Preserved Natural Fibers with Injection Molding Compounding (IMC)

The paper shows selected results of a comprehensive national network activity related to the integrated value chain for new whole plant based fibrous raw materials. Therefore, both the supply of raw materials and the processing with the innovative one step technology injection molding compounding (IMC)—are optimized. As a result the fiber length in the product is longer compared to the standard two-step process with pelletizing. The new technology helps in improving the manufacturing of fiber reinforced composites by considering the integrated value chain.

Natural unidirectional sheet processes for fibre reinforced bioplastics

Technical natural fibre semi-finished products are mainly used in lightweight automotive components as random fiber mats which are often combined with petrochemical matrix resins for large series production process. However, random fiber arrangement and limited fiber length restrain the complete utilization of the material-inherent strength reserves of natural fibers. With high-levels of petroleum-based plastics (about 20-50 wt -%) in the structure, these applications have a clear potential in terms of eco-friendliness and sustainability. The development of new fully bio-based composites and efficient manufacturing methods suitable for series processing is the purpose of the current sub-project C4 “Flexible textile / plastics processes with renewable raw materials” in the framework of the Excellence Cluster MERGE EXC 1075, funded by DFG (Deutsche Forschungsgemeinschaft). A high-efficiency in terms of mass-production, reproducibility and flexibility requires the performance of successive steps in the manuf...

Natural Fibre Reinforced Bioplastics - Innovative Semi-Finished Products for Series Production

The development of innovative bio-based composites with efficient manufacturing processes is the purpose of the current project C4 in the framework of the Excellence Cluster MERGE EXC 1075, funded by DFG (Deutsche Forschungsgemeinschaft). Efficiency in terms of mass-production, reproducibility and flexibility requires the performance of successive steps in the manufacture of semi-finished and final bio-based products. About bio-based materials, natural fibres composite (NFC) prepregs have been recently investigated as a potential cost-efficient semi-finished product. By means of continuous production processes, prepreg rolls can be manufactured with unidirectional natural fibres (flax) fabrics as reinforcement and thermoplastic biopolymers films as matrix. The used natural fibre non-crimp fabrics are made of high twisted yarns. For a better impregnation and higher stiffness properties, non-crimp fabrics with non-twisted yarns, which have been lastly developed by natural fibres suppliers, represent an appropriate solution. A second suitable option is the substitution of the biopolymer films, whose impermeability does not facilitate the release of humidity from the natural fibres while the impregnation, by produced low cost thermoplastic spunlace fabrics with a higher permeability and lower reachable surface weights. With these material developments and innovative process optimizations suitable to natural fibres, NFC prepreg properties tend to be improved. From prepregs to finished parts can be implemented by discontinuous processes, with compression molding and back-injection molding, or by continuous processes, with devices gathering several stages such as cutting, stacking, points welding, pre-heating and back injection molding. By stacking, a multi-axial orientation of prepregs can be performed in order to optimize the placement of reinforcing yarns according to the possible load path of future products. The mechanical properties profile of the combination of non-crimp natural fibres fabrics with thermoplastic films or thermoplastic spunlace fabrics has been here studied in detail with press-engineered samples and has confirmed the potential as an alternative to glass fibre-reinforced composite.