Optimisation of charge ratios for ball milling synthesis: agglomeration and refinement of coconut shells
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Date
2018
Authors
Bello, S.A.
Agunsoye, J.O.
Adebisi, J.A.
Hassan, S.B.
Journal Title
Journal ISSN
Volume Title
Publisher
Engineering and Applied Science Research
Abstract
Agglomeration is an attraction of fine particles for one another due to their high surface energy, leading to formation of particle
colonies known as agglomerates. When a polymeric or metallic matrix is reinforced with particles, agglomerates usually create
regions of discontinuity or weak particle adhesion within the matrix and degrade mechanical properties of the resulting
composites. In ball-milling synthesis of nanoparticles, formation of agglomerates can be controlled through optimisation of
milling parameters. In this study, coconut shell (lignocellulosic) nanoparticles were synthesised by varying the charge ratios
from 2.5 to 40 at constant milling duration (70 hours), speed in terms of drum/vial rotation (194 revolution per minute) and
ball sizes (5- 60 mm). Assessment of the effects of charge ratios (CRs) on the morphologies and particles sizes of uncarbonised
coconut shell nanoparticles (UCSnp) was studied. The synthesised UCSnp were characterised using electron microscopy and
X-ray diffractometry (XRD). The results showed various morphologies and orientations of UCSnp with changes in the CRs.
Size determination using XRD and SEM revealed a reduction in particle size as the CR increased up to a value of 10. At higher
CRs, further reduction in the average particle size was not observable. This could be linked to a balance between particle
refinement and agglomeration at these higher CRs. Although particle agglomeration was apparent above CR values of 10,
sizes of the UCSnp obtained above this CRs were much smaller than the initial size (37 μm) of the coconut shell precursor
particles. This affirmed the ball milling synthesis as a particle refinement process, but not a coarsening/agglomeration process.
The results obtained from statistical analyses show agreement with experimental results.
Description
Keywords
Electron microscopy, Surface energy, X-ray study, Agglomerates, Synthesis
Citation
Bello, S.A. Agunsoye, J.O. Adebisi, J.A. Hassan, S.B. (2018). Optimisation of charge ratios for ball milling synthesis: agglomeration and refinement of coconut shells.Engineering and Applied Science Research;45(4):262-272