Novel manufacturing process for natural fibre composites out of biobased and biodegradable materials

The use of natural fibres is an approach to address the issue of sustainability in the field of composites. With regard to potential recycling strategies for composites, natural fibres are particularly relevant in conjunction with biodegradable matrix materials. In addition to polysaccharides and lipids, proteins offer potential. Compared to conventional matrix materials such as epoxy resins, these kinds of natural materials cause some challenges in terms of processing. Combining two existing processes made it possible to produce flax fibre composites with a matrix based on the protein zein sourced from agricultural industry residues. A pre-impregnation of the flax fibres with the matrix ensures adequate infiltration of the flax fibres. By alternating stacking with films of the same matrix material, a good fibre-matrix bonding could be achieved, as shown with transverse tensile tests. By further modifying the matrix material, the mechanical properties were significantly improved. The developed manufacturing technique allows the reproducible fabrication of laminates with high quality. Therefore, unidirectional and cross-ply [0/90]2s flax fibre biocomposites were manufactured and characterised in terms of mechanical performance and optical damage analysis. While the unidirectional specific tensile strength of the novel biocomposites with protein-based matrix already reaches approx. 80 % of the best epoxy-based flax fibre composites available on the market, the achieved stiffness is already on the same level. Consequently, a comparison with other “green composites” highlights the competitiveness of fully biodegradable materials. The major advantage of the presented biocomposites, which makes them superior to all others in terms of sustainability, is the degradation by biological activity demonstrated in home composting. Recycling is thus possible even in the simplest conceivable process. Industrial composting at elevated temperatures and shredding of the composites can additionally lead to faster decomposition rates.

Subjects

Agricultural Industry Residues

Biocomposites

Flax

Sustainability

Zein Protein

DDC Class

620: Engineering

333.7: Natural Resources, Energy and Environment

660: Chemistry; Chemical Engineering

Options

Novel manufacturing process for natural fibre composites out of biobased and biodegradable materials