Utilising bio-based plasticiser castor oil and recycled PLA for the production of conductive additive manufacturing feedstock and detection of bisphenol A

Abstract

The production of electrically conductive additive manufacturing feedstocks from recycled poly(lactic acid) (rPLA), carbon black (CB), and bio-based plasticiser castor oil is reported herein. The filament was used to print additively manufactured electrodes (AMEs), which were electrochemically benchmarked against geometrically identical AMEs printed from a commercially available conductive filament. The castor oil/rPLA AMEs produced an enhanced heterogeneous electrochemical rate constant of (1.71 ± 0.22) × 10⁻³ cm s⁻¹ compared to (0.30 ± 0.03) × 10⁻³ cm s⁻¹ for the commercial AME, highlighting the improved performance of this filament for the production of working electrodes. A bespoke electroanalytical cell was designed and utilised to detect bisphenol A (BPA). The AMEs made from the castor oil/rPLA gave an enhanced electroanalytical performance compared to the commercial filament, producing a sensitivity of 0.59 μA μM⁻¹, a LOD of 0.10 μM and LOQ of 0.34 μM. This system was then successfully applied to detect BPA in spiked bottled and tap water samples, producing recoveries between 89–104%. This work shows how the production of conductive filaments may be done more sustainably while improving performance.