Atmospheric DBD plasma treatment and its impact on the triboelectric charging of model granular polymers

In this work, the triboelectric charging behavior of non-brominated model polymer particles representative of plastics commonly found in waste electrical and electronic equipment (WEEE): ABS (acrylonitrile butadiene styrene), PC (polycarbonate) and PS (polystyrene) was investigated using a fluidized bed tribocharger. These polymers are widely used in both fundamental research and industrial applications due to their well-characterized properties, thermal stability and availability in granular form. The effects of charging time, tribocharger wall material (PVC and PMMA) and surface modification by dielectric barrier discharge (DBD) plasma treatment were systematically examined. The results show that triboelectric charging is strongly influenced by particle–wall interactions and treatment conditions. With a PVC wall, ABS, PC and PS acquired positive charges that increased to a maximum before decreasing with charging time, while PS exhibited a polarity reversal with a PMMA wall. DBD plasma treatment not only enhanced the magnitude of the triboelectric charge but also induced polarity reversal. FTIR-ATR analysis revealed the introduction of oxygen containing polar functional groups (C=O, $-$OH and C$-$O) on all treated particles, confirming plasma induced surface oxidation as the mechanism responsible for the observed changes in triboelectric charging dynamics.