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

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 & PLUSMN; 0.22) x 10(-3) cm s(-1) compared to (0.30 & PLUSMN; 0.03) x 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 & mu;A & mu;M-1, a LOD of 0.10 & mu;M and LOQ of 0.34 & mu;M. 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.