Experimental study of triboelectric charging of polyethylene powders: Effect of humidity, impact velocity and temperature

Jantač, Simon; Konopka, Ladislav; Košek, Juraj

doi:10.1016/j.apt.2018.10.017

Cited by 14 publications

(4 citation statements)

References 44 publications

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“…However, the observed surprisingly high discharge rate in one case still lacks a better understanding and will be a part of our future studies. Let us note that similar fast change in the charge was observed also by Jantač et al [40] after the change of humidity followed up by tribocharging. Fig.…”

Section: P\ \P and P\ \W Charging Dynamics In A Sequencesupporting

confidence: 85%

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

et al. 2020

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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.

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Section: P\ \P and P\ \W Charging Dynamics In A Sequencesupporting

confidence: 85%

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

et al. 2020

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“…It has been observed that the charge generated in a monodisperse mixture of identical polymer particles drops off at a certain critical humidity level [71]. Further experiments have also shown that saturation charge is decreased when humidity increases [61,72,73].…”

Section: Methods Validation 321 Relative Humidity Has Negligible Effe...mentioning

confidence: 98%

“…On a single contact, the amount of charge transferred between two surfaces is given by ∆q = k c C p V c , where C p is the capacitance between the two surfaces, V c is the contact potential difference, and k c is a charging constant. This charging constant accounts for external factors such as the effects of humidity or temperature [61]. Once charge has been transferred, the two surface potentials will change and V c will get smaller.…”

Section: Introductionmentioning

confidence: 99%

The effect of particle size and relative humidity on triboelectric charge saturation

Cruise

Hadler

Starr

et al. 2022

J. Phys. D: Appl. Phys.

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Triboelectric charging is present in numerous technologies and everyday processes, providing both problems and opportunities. Despite this, there is no generalised model for the amount of charge that will build up on surfaces in contact. Here, we develop a new model for the saturation charge on triboelectrically charged spherical insulators, accounting for both equalisation of surface potentials and electrical breakdown of the surrounding medium. Experiments are conducted under controlled temperature and humidity using two independent methods, measuring the saturation charge on polymer spheres contacting grounded stainless steel. The results verify our equalisation of surface potentials model which describes how saturation charge density increases for smaller particle sizes. Key triboelectric properties are calculated: The estimated saturation charge on a flat surface and the equalisation potential between different materials, which can be used to predict charge saturation and quantify a triboelectric series. The transition radius below which electrical breakdown will cause saturation of charge is also calculated theoretically. Limitations to the model are demonstrated experimentally. As particle size reduces, a point is reached at which the electrostatic adhesion of particles to the grounded charging surface prevents further charge build-up. Furthermore, it is found that the saturation charge for smaller particles in humid conditions is greatly reduced. These calculations, and the demonstrated procedure, can serve as a tool for the design of technologies and processes influenced by triboelectric charge build-up, including triboelectric nanogenerators and electrostatic mineral separators.

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“…However, unwanted charging can cause severe negative consequences. Particle adhesion to vessel walls, also known as “sheeting”, can cause uneven inlet flow or blockages. − Agglomeration and segregation of charged particles can cause blending problems and threaten the homogeneity of powder formulations . Excessive charge build-up can result in electrostatic discharge, posing a significant fire and explosion risk. , …”

Section: Introductionmentioning

confidence: 99%

Prediction of the Effective Work Function of Aspirin and Paracetamol Crystals by Density Functional Theory─A First-Principles Study

Middleton,

Scott,

Storey

et al. 2023

Crystal Growth & Design

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Crystals of active pharmaceutical ingredients (API) are prone to triboelectric charging due to their dielectric nature. This characteristic, coupled with their typically low density and often large aspect ratio, poses significant challenges in the manufacturing process. The pharmaceutical industry frequently encounters issues during the secondary processing of APIs, such as particle adhesion to walls, clump formation, unreliable flow, and the need for careful handling to mitigate the risk of fire and explosions. These challenges are further intensified by the limited availability of powder quantities for testing, particularly in the early stages of drug development. Therefore, it is highly desirable to develop predictive tools that can assess the triboelectric propensity of APIs. In this study, Density Functional Theory calculations are employed to predict the effective work function of different facets of aspirin and paracetamol crystals, both in a vacuum and in the presence of water molecules on their surfaces. The calculations reveal significant variations in the work function across different facets and materials. Moreover, the adsorption of water molecules induces a shift in the work function. These findings underscore the considerable impact of distinct surface terminations and the presence of molecular water on the calculated effective work function of pharmaceuticals. Consequently, this approach offers a valuable predictive tool for determining the triboelectric propensity of APIs.

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Experimental study of triboelectric charging of polyethylene powders: Effect of humidity, impact velocity and temperature

Cited by 14 publications

References 44 publications

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

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

The effect of particle size and relative humidity on triboelectric charge saturation

Prediction of the Effective Work Function of Aspirin and Paracetamol Crystals by Density Functional Theory─A First-Principles Study

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