Sustainable Polymer Composites: Mechanical Characterization of Recycled High Density Polyethylene With Post‐Consumer Diatomaceous Earth

ABSTRACT The beer industry seeks sustainable solutions to reduce its environmental impact, including the proper management of waste materials. Diatomaceous earth (DE), used as a filtration aid in beer clarification, and high‐density polyethylene (HDPE) from discarded beer crates are significant waste streams. After use, DE becomes saturated with organic residues and is typically discarded. This study repurposes post‐consumer DE as a reinforcing agent for recycled HDPE to improve its mechanical properties. DE was dried using two methods: a disaggregator with a particle dryer (DEdryer) and a spray dryer (DEspray). Characterization included thermogravimetric analysis (TGA), nitrogen gas adsorption–desorption isotherms, and Brunauer, Emmett, and Teller (BET) equation to measure specific surface area, x‐ray fluorescence (XRF), x‐ray diffraction (XRD), particle size distribution analysis, and field‐emission gun scanning electron microscopy (FEG‐SEM). Recycled HDPE composites with 5, 10, 15, and 20 wt% DE were produced via twin‐screw extrusion and injection molding. Rheological, mechanical (tensile and Izod impact tests), and morphological (FEG‐SEM) analyses were conducted. Composites with DEdryer showed superior tensile strength and elastic modulus at higher DE contents (15–20 wt%) but exhibited reduced impact resistance due to poor dispersion and increased brittleness. These results highlight the potential of DEdryer to enhance recycled HDPE properties while promoting circular economy practices, reducing waste, and making the beer industry more resource‐efficient and environmentally friendly.