Quantification of Triboelectric Charging of a Polypropylene-based Powder During Wall Friction Shear Tests

The phenomena of triboelectric charging, which occur unintentionally while handling powders, have been thoroughly investigated in several works reported in the literature. However, little is known about how wall friction in shear action affects powder tribocharging. This study examines the effects of friction on the tribocharging of a polypropylene-based powder during the shearing on a lid made out of a wall coupon, with particular focus on the influence of the shear cell and lid materials, particularly polylactic acid (PLA) polymer and metal. The results show that the triboelectric charge produced by shearing the powder inside a PLA cell is similar for a metal lid and a polytetrafluoroethylene (PTFE) lid, with values of about 20.03 nC and 21.5 nC, respectively. On the other hand, the triboelectric charge produced by a metal cell with a metal lid is polarity-opposite to the charge created by a PTFE lid on the identical metal cell. In particular, a charge of 16.71 nC was recorded with the metal lid and -12.4 nC with the PTFE lid.