Effect of powder dispersity on rheological behavior

Cilj ovog rada bio je odrediti raspodjelu veličina čestica, kut mirovanja, nasipnu gustoću, gustoću nakon potresanja te indekse koji pokazuju svojstva tečenja prašaka i mješavina prašaka. Na temelju dobivenih podataka određene su karakteristike prašaka i karakteristike mješavina tih prašaka. U eksperimentu je korišteno sedam komponenata iz kojih je pripremljeno sedam različitih mješavina prašaka. Kao osnovna komponenta u svim mješavinama korištena je granulirana saharoza dobivena granuliranjem usitnjene saharoze p.a. uz dodatak veziva polivinilpirolidona (PVP). Mikrokristalinična celuloza (MCC), manitol, laktoza te PanExcea MC200G izvorna i granulirana, korištene su kao punila u mješavinama. U svaku mješavinu, kao sredstvo za klizenje, dodan je magnezijev stearat. Na temelju raspodjele veličina čestica i svojstva tecivosti prašaka i mješavina prašaka može se zaključiti da veliki udio čestica u području većih vrijednosti dovodi do bolje tecivosti prašaka. Također se pokazalo da širina raspodjele nema značajan utjecaj na svojstva tecivosti mješavina prašaka.The purpose of this work was to determine the particle size distribution, angle of repose, bulk density, tapped density and indexes that show the flow properties of powders and powder mixtures. Based on experimental and calculated data, the specific characteristics of powders and mixture were determined. In the experiments, seven different powder mixtures were prepared combining seven components. Sucrose obtained by granulation of grinded sucrose with polyvinylpyrrolidone (PVP) as a binder was used as a core component in all mixtures. Microcrystalline cellulose (MCC), mannitol, lactose and PanExcea MC200G original and granulated, were used as fillers in the mixtures. Magnesium stearate was added as lubricant. Based on the particle size distribution and the flow properties of powders and mixtures it can be concluded that a greater proportion of large particles leads to better flow properties of powders. Also, it was shown that the distribution span has no significant effect on the flow properties of powder mixtures