scholarly journals Ultrasonic application and spray drying during amorphous calcium phosphate synthesis

2019 ◽  
Vol 8 (4) ◽  
pp. 711-714
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Calcium Phosphate ◽  
Spray Drying ◽  
Amorphous Calcium Phosphate ◽  
Calcium Phosphates ◽  
Calcium Content ◽  
Synthesis Process ◽  
Particle Sizes ◽  
Ultrasound Application

Hydroxyapatite, amorphous calcium phosphates, calcium triphosphate and calcium octaphosphate are the main components present in bones and teeth. Calcium phosphates are easily synthesized, playing an important role in regenerative medicine, being able to be used as bone implants. There are different ways of synthesizing phosphates, the most commonly used being wet chemical method. The objective of this work was to study the influence of the use of ultrasound and spray drying on the synthesis of amorphous calcium phosphate. Two synthetic variants were studied. One without ultrasound application and the other with ultrasound application. The samples obtained were characterized by X-ray diffraction, FTIR spectroscopy and scanning electron microscopy. The particle size by electron microscopy and the calcium content by atomic absorption was determined. The results showed that when spray drying is applied, particle sizes of less than 261 nm are obtained in the samples synthesized without ultrasound application, being less than 59 nm in the samples synthesized with ultrasound application. The statistical analysis by ANOVA showed significant differences between the particle sizes of the samples synthesized without ultrasound application and the samples synthesized by applying ultrasound. In both cases the particles were spherical. The results obtained show that the application of ultrasound during the synthesis process decreases the particle size, increasing the surface area, which favors the spray drying process.

Effect on Drying Conditions on Amorphous Calcium Phosphate

2014 ◽  
Vol 631 ◽  
pp. 99-103 ◽  
Author(s):  
Agnese Brangule ◽  
Kārlis Gross
Keyword(s):  
Particle Size ◽  
Calcium Phosphate ◽  
Amorphous Calcium Phosphate ◽  
Intermediate Phase ◽  
Calcium Phosphates ◽  
Ftir Spectra ◽  
The Body ◽  
Drying Methods ◽  
Dry Conditions ◽  
Drying Conditions

Amorphous calcium phosphate (ACP) plays an important role in the body and can be used as an intermediate phase for forming calcium phosphates. All ACPs are thermodynamically unstable compounds, unless stored in dry conditions or at low temperature (-18oC), and spontaneously undergo transformation to crystalline calcium phosphates (CaP). This work will investigate the influence of drying on the stability of ACP. ACPs powders were prepared by wet synthesis; mixing solution made of Ca (NO3)2∙4H2O and 30% ammonia with (NH4)2HPO4 and (NH4)2CO3 solution at room temperature. The suspension was stirred, filtered and washed several times with deionized water containing ammonia. ACP samples were dried at different conditions and with different drying agents (DA). XRD and FTIR spectra showed poorly crystallinity powders after drying. Some FTIR spectra indicated residual organic compounds from drying. The Rietveld’s method and Schrrer’s relationship estimated the particle size (0.5 – 20 nm) of ACP. Thermogravimetry (TG) revealed that the moisture (7% – 25%) is released upon drying, and the drying agents have no significant effect on. The drying methods are ordered to show which the most effective for removing moisture. By changing the drying conditions, it is a possible to obtain poorly crystalline ACPs with different particle size and moisture content.

Effect of Synthesis Temperature and Ca/P Ratios on Specific Surface Area of Amorphous Calcium Phosphate

2016 ◽  
Vol 721 ◽  
pp. 172-176 ◽  
Author(s):  
Jana Vecstaudza ◽  
Janis Locs
Keyword(s):  
Calcium Phosphate ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Amorphous Calcium Phosphate ◽  
Calcium Phosphates ◽  
Synthesis Temperature ◽  
Molar Ratios ◽  
Different Temperatures ◽  
Low Crystalline

Amorphous and low crystalline calcium phosphates are prospective candidates for bone implant manufacturing. Amorphous calcium phosphate (ACP) preparation technologies could be improved in terms of specific surface area (SSA) of obtained products. Current study is dedicated to the effect of synthesis temperature and Ca and P molar ratios (Ca/P) on SSA of ACP. Higher SSA can improve bioactivity of biomaterials. ACP was characterized by XRD, FT-IR, SEM and BET N2 adsorption techniques. Spherical nanoparticles (<45 nm in size) were obtained independently of initial Ca/P ratio and synthesis temperature. For the first time comparison of SSA was shown for ACP obtained at different temperatures (0 °C and 20 °C) and Ca/P molar ratios (1.5, 1.67 and 2.2).

Synthesis and Properties of α-Tricalcium Phosphate from Amorphous Calcium Phosphate as Component for Bone Cements

2016 ◽  
Vol 721 ◽  
pp. 182-186
Author(s):  
Zilgma Irbe ◽  
Dagnija Loca ◽  
Agnese Pura ◽  
Liga Berzina-Cimdina
Keyword(s):  
Heat Treatment ◽  
Particle Size ◽  
Calcium Phosphate ◽  
Bone Defect ◽  
Tricalcium Phosphate ◽  
Amorphous Calcium Phosphate ◽  
Heat Treating ◽  
Bone Cements ◽  
Important Ingredient ◽  
Reactive Particles

α-Tricalcium phosphate is an important ingredient of calcium phosphate bone cements, which are used for bone defect augmentation and repair. In this study sub-micrometre sized α­tricalcium phosphate particles were synthesized by heat treating amorphous calcium phosphate. Size of synthesized particles depended on duration and temperature of heat treatment. Longer duration and higher temperatures produced larger particles. The reactivity of synthesized particles did not correlate with particle size – the smallest particles did not have the highest reactivity. The most reactive particles were prepared at 700-800 °C. The prepared particles were more reactive than those of conventionally synthesized α-tricalcium phosphate.

Amorphous Calcium Phosphate Based Polymeric Composites: Effects of Polymer Composition and Filler's Particle Size on Composite Properties

2005 ◽  
Vol 284-286 ◽  
pp. 737-740 ◽  
Author(s):  
Drago Skrtic ◽  
S.Y. Lee ◽  
Joseph M. Antonucci ◽  
D.W. Liu
Keyword(s):  
Particle Size ◽  
Calcium Phosphate ◽  
Physicochemical Properties ◽  
Amorphous Calcium Phosphate ◽  
Fine Tuning ◽  
Polymer Composition ◽  
Ion Release ◽  
The Matrix ◽  
Carboxylic Groups ◽  
Composite Properties

This study explores how a) the resin grafting potential for amorphous calcium phosphate (ACP) and b) particle size of ACP affects physicochemical properties of composites. Copolymers and composites were evaluated for biaxial flexure strength (BFS), degree of vinyl conversion (DC), mineral ion release and water sorption (WS). Milled ACP composites were superior to unmilled ACP composites and exhibited 62 % and 77 % higher BFS values (dry and wet state, respectively). The average DC of copolymers 24 h after curing was 80 %. DC of composites decreased 10.3 % for unmilled Zr-ACP and 4.6 % for milled Zr-ACP when compared to the corresponding copolymers. The WS increased as follows: copolymers < milled Zr-ACP composites < unmilled Zr-ACP composites. The levels of Ca and PO4 released from both types of composites increased with the increasing EBPADMA/TEGDMA ratio in the matrix. They were significantly above the minimum necessary for the redeposition of HAP to occur. No significant consumption of released calcium by the carboxylic groups of methacryloxyethyl phtahalate (MEP) occurred at a mass fraction of 2.6 % of MEP in the resin. Improvements in ACP composite’s physicochemical properties are achieved by fine tuning of the resin and improved ACP’s dispersion within the polymer matrix after ball-milling.

Factors Affecting Strength of Agglomerates Formed During Spray Drying of Nanophase Powders

1994 ◽  
Vol 346 ◽  
Author(s):  
A. Maskara ◽  
D.M. Smith
Keyword(s):  
Surface Tension ◽  
Particle Size ◽  
Spray Drying ◽  
Particle Surface ◽  
Strength Distribution ◽  
Particle Sizes ◽  
Factors Affecting ◽  
Surface Hydroxyl ◽  
Alcohol Water ◽  
Nanosized Silica

ABSTRACTNanosized silica particles dispersed in various solvents were spray dried and the change in size distribution, agglomerate strength, and strength distribution was determined. The effect of solvent surface tension, pH, and particle surface chemistry on strength of agglomerates formed during spray drying was studied for particle sizes between 15 and 500 nm. Alcohol/water mixtures having different surface tension, and water at different pH levels, were employed to separate the effects of capillary pressure and surface hydroxyl condensation reactions. The agglomerate strength was determined using an ultrasonic measurement technique. The particle size was determined using sedimentation. The strength and strength distribution of agglomerates was found to depend on the solvent surface tension, solubility (pH), and primary particle size.

scholarly journals Investigation on Variables Contributing to the Synthesis of C-S-H/PCE Nanocomposites by Co-Precipitation Method

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7673
Author(s):  
Ziyang You ◽  
Jing Xu
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Precipitation Method ◽  
Synthesis Process ◽  
Orthogonal Experimental Design ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Ultra Fine Particle ◽  
Early Performance ◽  
Co Precipitation

The usage of nanoscale calcium silicate hydrate (nano C-S-H) proved to have an excellent promotion effect on the early performance of concrete as nano C-S-H with ultra-fine particle size can act as seeding for cement hydration. Therefore, it is of importance to tune the particle size during the synthesis process of nano C-S-H. In this paper, the influence of several variables of the particle size distribution (PSD) of nano C-S-H synthesized by chemical co-precipitation method with the aid of polycarboxylate (PCE) was studied by orthogonal experimental design. In addition, the composition, microstructure, and morphology of the C-S-H/PCE nanocomposites were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectrum. The results showed that the concentration of reactants had a significant impact on the PSD of C-S-H/PCE nanocomposites, followed by the dosage of dispersant. Ultrasonic treatment was effective in breaking the C-S-H/PCE aggregates with unstable agglomeration structures. The change in synthetic variables had a negligible effect on the composition of the C-S-H/PCE nanocomposites but had a significant influence on the crystallinity and morphology of the composites.

scholarly journals Spray-drying-derived amorphous calcium phosphate: a multi-scale characterization

2020 ◽  
Vol 56 (2) ◽  
pp. 1189-1202
Author(s):  
Sylvain Le Grill ◽  
Jeremy Soulie ◽  
Yannick Coppel ◽  
Pierre Roblin ◽  
Pierre Lecante ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Spray Drying ◽  
Amorphous Calcium Phosphate ◽  
Multi Scale ◽  
Scale Characterization

A Comparative Study of Pathological Nanomineral Aggregates with Distinct Morphology in Human Aortic Atherosclerotic Plaques

2021 ◽  
Vol 21 (1) ◽  
pp. 547-554
Author(s):  
Yuan Li ◽  
Changqiu Wang ◽  
Anhuai Lu ◽  
Kang Li ◽  
Xiao Cheng ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Calcium Phosphate ◽  
Amorphous Calcium Phosphate ◽  
Microscopic Analysis ◽  
Atherosclerotic Plaques ◽  
Carbonate Hydroxyapatite ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Precursor Phase ◽  
Exact Difference

Calcification exists in atherosclerotic plaques in the form of nanomineral aggregates and is closely related to the development of atherosclerosis. Spheroidal and massive calcification are two major types of calcification found in atherosclerotic tissue. However, the exact difference between these two types of calcification is still not clear. Samples composed entirely of spheroidal calcifications and massive calcifications were isolated from aortic atherosclerotic plaques and tested using both bulk and microscopic analysis techniques. Scanning electron microscopy and transmission electron microscopy showed that spheroidal calcifications had a core–shell structure. Massive calcifications were composed of randomly arranged nanocrystals. Synchrotron radiation X-ray diffraction, Raman spectroscopy and selected area electron diffraction showed amorphous calcium phosphate, whitlockite and carbonate hydroxyapatite all existing in spheroidal calcification, while massive calcification only consisted of carbonate hydroxyapatite. We conclude that amorphous calcium phosphate may act as a precursor phase of spheroidal calcifications that eventually transforms into a crystalline phase, while whitlockite in lesions could aggravate the progression of atherosclerosis.

Synthesis and Characterization of Hydrated Calcium Phosphate: Precursors for Obtaining Biocements

2014 ◽  
Vol 798-799 ◽  
pp. 443-448
Author(s):  
Priscila Ferraz Franczak ◽  
Nelson Heriberto Almeida Camargo ◽  
Pricyla Corrêa ◽  
Enori Gemelli
Keyword(s):  
Calcium Phosphate ◽  
Biomedical Applications ◽  
Fine Particles ◽  
Calcium Phosphates ◽  
Synthesis Method ◽  
Synthesis Process ◽  
Promising Alternative ◽  
Hydrated Calcium ◽  
Reactive Method

Calcium phosphates biocements are biomaterials that present crystallographic and mineralogical characteristics similar to human skeletal structure. This has led to the development of new calcium phosphates biomaterials for biomedical applications, especially biomaterials for repairing defects and bone reconstruction. Calcium phosphates biocements are a promising alternative in biomedical applications, for they are easy to mold, they have good wettability, hydration and hardening capacity during its application in biological means. This work aimed at the synthesis of hydrated calcium phosphates powder, through a simple reactive method, which will be the basis for the production of calcium phosphate biocimentos with self-setting reaction. Three calcium phosphates compositions were produced via CaCO3/phosphoric acid reactive method in the ratios Ca/P = 1,5; 1,6 e 1,67 molar. The presented results are associated to hydrated powder morphology and synthesis process control. Scanning Electron Microscopy (SEM) helped with the morphological characterization of the powders, the laser analysis method was used for determining particle size and the Fourier Transformed Infrared Spectroscopy (FTIR) gave support to the identification of H2O e PO43-grouping vibrational bands. The work showed that for the different powder compositions the hydrated calcium phosphate phase is formed by clustered fine particles. This demonstrated that the chosen synthesis method permits the obtention of hydrated calcium phosphates, precursors for later biocement production.

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