Fully biobased composite and fiber‐metal laminates reinforced with Cynodon spp. fibers

• Published in: Polymer composites 2023-01, Vol.44 (1), p.453-464
• Main Authors: Germano Braga, Guilherme, Assunção Rosa, Fábio, César dos Santos, Júlio, Pino, Gilberto Garcia, Panzera, Tulio Hallak, Scarpa, Fabrizio
• Format: Article
• Language: English
• Subjects: Aluminum; bio fibers; biomaterials; Biomedical materials; Castor oil; Cold pressing; composites; Drop towers; Factorial design; Fiber composites; Fiber-metal laminates; Industrial applications; Mechanical properties; Natural resources; Polymer matrix composites; Polymers; Polyurethane resins; sandwich panels; Static loads; Sustainable development; Weight reduction
• ISSN: 0272-8397; 1548-0569
• DOI: 10.1002/pc.27109

Biobased products promote efficient industrial use of natural resources, directly contributing to circular economy principles and sustainable development. This work investigates biocomposites made from Hay Tifton 85 grass fibers (i.e., Cynodon spp.) combined with castor oil polyurethane or epoxy matrices and their evaluation as core materials for novel fiber metal laminates (FMLs). A full factorial design is used to identify the effects of polymer type and fiber length on the tensile, flexural, compression and impact properties of composites. A cold pressing technique is used to manufacture random‐fiber composites and FMLs made of aluminum skins. The castor oil matrix shows promise for dynamic applications, while the epoxy matrix provides better performance under static loads. Composites achieved improved mechanical properties attributed to their lower porosity. The mechanical properties of FMLs under tensile flexural and impact (Charpy and drop tower) are also considerably higher than those of fiber‐reinforced polymers. Fully biobased laminates offer potential advantages compared to epoxy polymer composites. Their use as cores in FMLs can be extended to applications related to the automotive, civil construction and aeronautical sectors, fostering sustainable industrial designs. This work investigates biocomposites made from Hay Tifton 85 grass fibers (i.e., Cynodon spp.) combined with castor oil polyurethane or epoxy matrices and their evaluation as core materials for novel fiber metal laminates (FMLs). A cold pressing technique is used to manufacture random‐fiber composites and FMLs made of aluminum skins.