Rheological properties of aqueous nanometric alumina suspensions

dc.contributor.advisor Mufit Akinc
dc.contributor.author Li, Chuanping
dc.contributor.department Materials Science and Engineering
dc.date 2018-08-25T01:24:32.000
dc.date.accessioned 2020-07-02T06:03:56Z
dc.date.available 2020-07-02T06:03:56Z
dc.date.copyright Thu Jan 01 00:00:00 UTC 2004
dc.date.issued 2004-01-01
dc.description.abstract <p>Colloidal processing is an effective and reliable approach in the fabrication of the advanced ceramic products. Successful colloidal processing of fine ceramic powders requires accurate control of the rheological properties. The accurate control relies on the understanding the influences of various colloidal parameters on the rheological properties.;Almost all research done on the rheology paid less attention to the interactions of particle and solvent. However, the interactions of the particles are usually built up through the media in which the particles are suspended. Therefore, interactions of the particle with the media, and chemical and physical properties of media themselves must influence the rheology of the suspension, especially for the dense suspensions containing nanosized particles.;This thesis addresses the rheological properties of nanometric alumina aqueous suspensions, and paying more attention to the interactions between particle and solvent, which in turn influence the particle-particle interactions. Dense nanometric alumina aqueous suspensions with low viscosity were achieved by environmentally-benign fructose additives.;The rheology of nanometric alumina aqueous suspensions and its variation with the particle volume fraction and concentration of fructose were explored. The adsorptions of solute (fructose) and solvent (water) on the nanometric alumina particle surfaces were measured and analyzed by TG/DSC, TOC, and NMR techniques. The mobility of water molecules in the suspensions and its variation with particle volume fractions and fructose additive were determined by the 17O NMR relaxation method. The interactions between the nanometric alumina particles in water and fructose solutions were investigated by AFM.;The results indicated that a large number of water layers were physically bound on the particles' surfaces in the aqueous suspension. The viscosity of the suspension increases dramatically when the solid volume fraction exceeds 30 vol.%. The overlap of physically adsorbed water layers at this level causes the sharp increase in viscosity. Fructose molecules can weaken the interactions between the particle surfaces and water molecules, as a consequence, they release some bound water layers from the surfaces to the bulk medium. It is believed that fraction of the water that is bound by the solid surface is reduced hence becoming available for flow. The oxygen-17 relaxation time decreased with the increase of particle volume fractions in the suspension. Fructose addition increased the overall water mobility in the suspension. Only part of the alumina particle surfaces was covered with fructose molecules. This adsorption of fructose molecules on the particle surfaces increased the pH of the suspension with a concomitant decrease in zeta-potential of the alumina nanoparticles. The interactions between the nanometric alumina particles in water to a large extent can be explained by the DLVO theory. However, the interactions between particles in fructose solutions cannot be well described by the DLVO theory. The interaction forces (magnitude and range) as well as adhesive force and surface tension between nanometric alumina particles were decreased with the fructose concentration.</p>
dc.format.mimetype application/pdf
dc.identifier archive/lib.dr.iastate.edu/rtd/797/
dc.identifier.articleid 1796
dc.identifier.contextkey 6080541
dc.identifier.doi https://doi.org/10.31274/rtd-180813-12795
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath rtd/797
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/80905
dc.language.iso en
dc.source.bitstream archive/lib.dr.iastate.edu/rtd/797/r_3136330.pdf|||Sat Jan 15 01:56:46 UTC 2022
dc.subject.disciplines Materials Science and Engineering
dc.subject.keywords Materials science and engineering
dc.title Rheological properties of aqueous nanometric alumina suspensions
dc.type article
dc.type.genre dissertation
dspace.entity.type Publication
relation.isOrgUnitOfPublication bf9f7e3e-25bd-44d3-b49c-ed98372dee5e
thesis.degree.level dissertation
thesis.degree.name Doctor of Philosophy
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