This study investigates the valorization of polyethylene household waste through chemical modification to develop environmentally sustainable composite materials. Secondary polyethylene (PE) was treated with elemental sulfur and melamine as chemical modifiers to enhance its properties. The modified PE was characterized using advanced spectroscopic techniques, including Fourier-transform infrared spectroscopy (FTIR) and other analytical methods, in accordance with ISO standards. Physical and mechanical properties, such as tensile strength, elongation at break, and hardness, were systematically evaluated to assess the performance of the resulting composites. The integration of melamine and chemically modified sulfur into secondary PE yielded materials with improved mechanical robustness and functional characteristics suitable for various industrial and consumer applications. This approach demonstrates an effective strategy for reducing polyethylene waste by converting it into value-added, functional composites, thereby promoting ecological sustainability and waste minimization. The findings underscore the potential of chemically modified secondary polyethylene as a viable resource for sustainable material development, contributing to environmental conservation and waste management efforts. Overall, this methodology offers a promising route for the reutilization of polyethylene household waste, aligning with principles of circular economy and ecological responsibility.