Triboelectric charging of polyethylene powders: Comparison of same-material and different-material contributions to the charge build-up

Abstract

The understanding of triboelectric charging of industrially important powders can help in avoiding or controlling the particle agglomeration and wall sheeting. We developed a new experimental approach to study both samematerial particle-particle (P\ \P) and different-material particle-wall (P\ \W) charging of nascent polyethylene (PE) particles born by catalytic polymerization. We constructed a simple tribocharger consisting of a metal box divided inside into several compartments filled with the PE sample and attached to the vibration shaker. The particle charge distribution was characterized by a self-constructed electrostatic separator. This way, we investigated the charging dynamics of PE particles colliding with other PE particles as well as with metal walls of the box compartments. Both P\ \P and P\ \W charging were measured either separately, or in sequence, and in combination of simultaneous P\ \P and P\ \W. The different-material P\ \W charging produced unipolarly charged particles and was much faster than the same-material P\ \P charging leading to bipolar particle charge distribution.

Influence of the Reynolds number from Reτ = 150 to 210 on size-dependent bipolar charging

“…The particle-wall collisions typically occur between objects of different materials, a situation that can be described by models that use a difference in the material property as a driving force for the charge transfer [19]. However, inter-particle collisions often occur between particles of identical material; thus, those models cannot describe experimentally observed bipolar charging in polydispersed systems of identical material [20,21]. New mosaic-based models were proposed that can explain those experiments based on the statistical variation of properties on otherwise identical materials [22,23].…”

Antibiotic-Powered Energy Harvesting: Introducing Benzylpenicillin as an Efficient Tribopositive Material for Triboelectric Nanogenerators

“…The output electrical energy of the TENG device is quadratically proportional to the surface charge density (σ sc ) [21,27]; therefore, more efficient tribopositive materials must be developed to considerably improve TENG performance. The widely adapted tribopositive materials that tend to easily lose electrons include polyamide (PA), polypyrrole (PPy), and polyethylene (PE) [30][31][32]. Despite the promising energy harvesting performance of synthetic polymers, in the past decades, the renewable and sustainable energy sources that can have a positive impact on the environment, have gained attention.…”

Eulerian models and kinetic theory closures for triboelectric charging in dense granular and gas-particle flows

“…It could be due to difference in surface properties or the size of the particles. The latter may be contributing but may not be the sole cause since a bipolar charge distribution was observed for both the largest and smallest particles in a broad PSD (particle size diameter) experiment (Konopka et al 2020). This type of behavior could be explained using the dipole amplification model as well.…”

“…The charging behavior for identical particles is only one piece of the puzzle for particleparticle collisions and it may be overshadowed by the effect of many other parameters relevant to gas-solid flow systems. For example, Konopka et al (2020) performed triboelectric charging experiments with poly-dispersed polyethylene particles, where they were able to differentiate between particle-wall and particle-particle charging (Konopka et al 2020). They found that particle-wall charging resulted in unipolarly charged particles, which agrees with the particlewall charging models, but the particle-particle charging lead to a bipolar charge distribution.…”

“…al. conducted experiments using a metal box connected to a shaker to study the charging behavior of polyethylene (PE) particles (Konopka et al 2020). At the end of each test, they used an electrostatic separator to collect particles of different polarities and charge magnitudes into a series of Faraday cups.…”