Rotomolded hybrid composites filled with Arundo donax L. and ignimbrite dust

Abstract

This work investigates the manufacture of hybrid polyethylene composites filled with Arundo donax L. fiber and ignimbrite dust obtained by rotational molding. The aim was to evaluate the performance of these sustainable materials and assess the potential valorization of natural and mineral residues, bringing together the potential benefits of using a fiber (with high aspect ratio) and a thin powder (benefitting the processability of the blends). All formulations were successfully processed, achieving well-formed parts with good filler dispersion and good aesthetics. Optical microscopic analyses confirmed a good incorporation for low content of both fillers, with a good distribution across the surface and section of the molded items. Thermal analysis showed only slight changes in stability and crystallinity, with a behavior similar to that of the neat polyethylene. Mechanical testing allows concluding that low filler contents (2.5–5 wt%) improved stiffness and flexural strength, whereas higher loadings led to reduced tensile and impact resistance due to agglomeration. Overall, the combination of Arundo donax L. fiber and ignimbrite powder enables the production of partially bio-based polyethylene composites with good performance and promising applications in sustainable manufacturing sectors.