Influence of Contaminant Removal Methods on the Thermomechanical Properties of Recycled Polyphenylsulfone Composites

Polyphenylsulfone composites are a lightweight alternative to brass for ammunition cartridges. While polyphenylsulfone is a recyclable material, residual heavy metal contaminants raise concerns in proper waste management and recycling conditions. This study presents a safe and cost-effective recycling strategy by first characterizing spent cartridge residue and then testing contaminant removal techniques. Inductively coupled plasma−optical emission spectroscopy identified lead as the major heavy metal contaminant (48 mg/kg). Notably, a simple washing procedure with either commercial soap or 5% acetic acid solution reduced all heavy metals to below US regulatory levels. When recycled via melt extrusion, these washed cartridges formed filaments with mechanical properties identical to neat cartridges and superior to unwashed cartridges. These results demonstrate that simple, environmentally friendly washing techniques can effectively remove heavy metal contaminants from spent polyphenylsulfone-based cartridges without compromising the mechanical performance of the recycled material.