Cactus-based solids and bio-composites for energy dissipation in defence and biomedical applications.

The recyclability, biodegradability and cost effectiveness of natural fibers combined with their high specific mechanical properties and lightweight structure have attracted significant interest. Cactus fibers demonstrate interesting energy dissipation properties under cyclic flexural loading as a fiber composite reinforcement and show a significantly high flexural to axial stiffness ratio of 7:1 and a 4.2-fold increase in the energy dissipation per matrix volume [1]. A multiscale materials characterization methodology [2] for the evaluation of morphological characteristics on a macro, meso, micro and nano scale through various microscopy methods revealed a fractal-like morphology for the cactus fibers. Composite materials were developed using Polypropylene (PP), and cactus fiber powder obtained via ball milling. Under compressive loading a 33% increase in the compressive modulus for PP composites at 0.4% by weight was observed. Morphological data obtained enabled the generation of 3D rendered models and 3D printed analogues of the cactus structure that revealed a high specific bending modulus as compared to their ASTM standard counterparts.