A Sustainable Writing Instrument Using Biodegradable PHA-Starch Polymers and Pollution-Derived Carbon Ink

This article explores a novel approach to sustainable writing instruments by combining two eco-innovations: a biodegradable pen body made from a PHA starch plastic blend and ink derived from carbon waste captured from pollution sources. Unlike prior efforts, where soot-based pigments required mixing with water for paint-like applications, this concept uses a safe, child-friendly polyol-based carrier system (propylene glycol, glycerin, PEG-400) to produce ink with the same texture and flow as everyday pen inks. The project highlights material selection, chemical safety, purification workflows, and the engineering of a refillable prototype. It bridges three perspectives: electrical and electronic systems thinking, material science, and sustainability impact.