Browsing by Author "Maidaniuc, Andreea"
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Item Open Access Facile synthesis and characterization of hydroxyapatite particles for high value nanocomposites and biomaterials(Elsevier, 2017-06-07) Miculescu, Florin; Mocanu, Aura-Cătălina; Dascălu, Cătălina Andreea; Maidaniuc, Andreea; Batalu, Dan; Berbecaru, Andrei; Voicu, Stefan Ioan; Miculescu, Marian; Kumar, Vijay; Ciocan, Lucian TomaLately Hydroxyapatite has gained a lot of research interest and intense focus due to its structural as well as compositional similarity to the components of human bone mineral. The conversion of calcium-rich precursors to hydroxyapatite could lead to the development of a new sustainable alternative with a valuable environmental and socio-economically impact. Still, current approaches faces lots of challenges in terms of synthesis parameters compatible to a reproducible route for calcium phosphates (hydroxyapatite included) synthesis. The optimization of Rathje synthesis route and characterization of biogenic derived calcium phosphates from dolomitic marble and Mytilus galloprovincialis seashells, constitutes the main goals of this study. The synthesized materials were characterized using FTIR, SEM coupled with EDS, and X-ray diffraction at all synthesis stages. Precursors were also subjected to thermal analysis and differential scanning calorimetry for thermal transformations investigations and dissociation temperature setting. This study suggests that acid quantity and magnetic stirring are the key-factors for Ca/P molar ratio adjustment, hence for the amount of naturally-derived hydroxyapatite. This research also contributes to the development of new strategies for further optimization of the conversion procedure and removal of residual components.Item Open Access Synthesis and characterization of jellified composites form bovine bone-derived hydroxyapatite and starch as precursors for robocasting(American Chemical Society, 2018-01-31) Miculescu, Florin; Maidaniuc, Andreea; Miculescu, Marian; Dan Batalu, Nicolae; Cătălin Ciocoiu, Robert; Voicu, Stefan Ioan; Stan, George E.; Kumar Thakur, VijayHydroxyapatite–starch composites solidify rapidly via jellification, making them suitable candidates for robocasting. However, many aspects related to hydroxyapatite powder characteristics, hydroxyapatite–starch interaction, and composites composition and properties need to be aligned with robocasting requirements to achieve a notable improvement in the functionality of printed scaffolds intended for bone regeneration. This article presents a preliminary evaluation of hydroxyapatite–starch microcomposites. Thermal analysis of the starting powders was performed for predicting composites’ behavior during heat-induced densification. Also, morphology, mechanical properties, and hydroxyapatite–starch interaction were evaluated for the jellified composites and the porous bodies obtained after conventional sintering, for different starch additions, and for ceramic particle size distributions. The results indicate that starch could be used for hydroxyapatite consolidation in limited quantities, whereas the composites shall be processed under controlled temperature. Due to a different mechanical behavior induced by particle size and geometry, a wide particle size distribution of hydroxyapatite powder is recommended for further robocasting ink development.