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Title: Tribo-electric charging of powders due to dispersion
Author: Zarrebini-Esfahani, Afsheen
Awarding Body: University of Leeds
Current Institution: University of Leeds
Date of Award: 2012
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Particle processing operations can give rise to tribo-electrification of particles. The electrostatic force can result in segregation/agglomeration of particle as well as adhesion to the walls of the processing equipment, which can affect the end product quality. The existing literature reveals that the current methods which are available for tribo-electric characterisation of particles are unsuitable for testing small quantities of sample. Moreover, these methods are mainly based on bulk powder testing. Limited work has been reported on tribo-electrification of powder due to aerodynamic dispersion, which is an area of great interest in particle characterisation processes. The objective of this work is to develop a methodology to investigate the effect of powder dispersion process on tribo-electrification of particles in small quantities. The dispersion unit of the Malvern's Morphologi G3 was adapted as a dispersion unit. Glass ballotini was used as model material and the effect of various factors on the extent of tribo-electric charging of the particles were investigated. The tribo-electric charging of the powders was compared with the data of a more extensively evaluated tribo-electric charging device. Eight different powders were tested by both devices. The findings reveal that particles acquire a similar charge polarity in both devices when colliding with the same material. However, the magnitude of the charge was significantly higher in the case of dispersion device. The methodology developed in this work has the potential to be used to characterise tribo-electric charging of small quantities of powders. The operating procedure is less time consuming compared to current charge characterisation devices. The methodology can also be used to test active pharmaceutical ingredients (APls), which are sparse in the early development stages.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available