scholarly journals Synthesis of Graphene Nanoribbons–Hydroxyapatite Nanocomposite Applicable in Biomedicine and Theranostics

2020 ◽  
Vol 1 (1) ◽  
pp. 6-18 ◽  
Author(s):  
Hassan Nosrati ◽  
Rasoul Sarraf-Mamoory ◽  
Amir Hossein Ahmadi ◽  
Maria Canillas Perez
Keyword(s):  
Solvothermal Method ◽  
Graphene Nanoribbons ◽  
Calcium Nitrate ◽  
Hydrogen Gas ◽  
Calcium Nitrate Tetrahydrate ◽  
Plasma Sintering ◽  
Transmission Electron ◽  
Nitrate Tetrahydrate ◽  
Spark Plasma ◽  
The Difference

In order to investigate the effect of graphene nanoribbons on the final properties of hydroxyapatite-based nanocomposites, a solvothermal method was used at 180 °C and 5 h for the synthesis of graphene nanoribbons–hydroxyapatite nanopowders by employing hydrogen gas injection. Calcium nitrate tetrahydrate and diammonium hydrogenphosphate were used as calcium and phosphate precursors, respectively. To synthesize the powders, a solvent containing diethylene glycol, anhydrous ethanol, dimethylformamide, and water was used. Graphene oxide nanoribbons were synthesized by chemical unzipping of carbon nanotubes under oxidative conditions. The synthesized powders were consolidated by spark plasma sintering methodat 950 °C and a pressure of 50 MPa. The powders and sintered samples were then evaluated using X-ray diffraction, Raman spectroscopy, high-resolution transmission electron microscopy, Vickers microindentation techniques, and biocompatibility assay. The findings of this study showed that the final powders synthesized by the solvothermal method had calcium to phosphate ratio of about 1.67. By adding a small amount of graphene nanoribbon (0.5%W), elastic modulus and hardness of hydroxyapatite increased dramatically. In biological experiments, the difference of hydroxyapatite effect in comparison with the nanocomposite was not significant. The findings of this study showed that graphene nanoribbons have a positive effect on the properties of hydroxyapatite, and these findings would be useful for the medical and theranostic application of this type of nanocomposites.

Influence of the Precipitation Temperature on Properties of Nanohydroxyapatite Powder for the Fabrication of Highly Porous Bone Scaffolds

2013 ◽  
Vol 587 ◽  
pp. 27-32 ◽  
Author(s):  
Cristian Parisi ◽  
Francesca Gervaso ◽  
Francesca Scalera ◽  
Sanosh Kunjalukkal Padmanabhan ◽  
Concetta Nobile ◽  
...  
Keyword(s):  
Calcium Nitrate ◽  
Bone Substitutes ◽  
Porous Scaffolds ◽  
Calcium Nitrate Tetrahydrate ◽  
High Porosity ◽  
Precipitation Temperature ◽  
Transmission Electron ◽  
Nitrate Tetrahydrate ◽  
Different Temperatures ◽  
Highly Porous

The aim of the present work is to study the influence of the precipitation temperature in the synthesis of nanohydroxyapatite (n-HAp) on the properties of the resulting n-HAp powder for the fabrication of highly porous scaffolds for bone tissue engineering. The n-HAp powder was obtained by a wet precipitation technique starting from calcium nitrate tetrahydrate (Ca (NO3)2*4H2O) and phosphoric acid (H3PO4) at different temperatures: 10°C, 37°C and 50°C. Highly porous scaffolds were fabricated using the three different powders by the sponge replica method and sintering at 1300°C. Combined X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses on powders indicated that on increasing the precipitation temperature the formation of pure n-HAp is accelerated, without significant changes in particles morphology and size. Scaffolds characterized by high porosity (89%) and good compressive strength (0.53 MPa for n-HAp prepared at 37°C) were obtained. XRD analyses on sintered n-HAp confirmed the thermal stability of the material. Therefore, the as-synthesized n-HAp powder can be successfully used for the fabrication of highly porous scaffolds as bone substitutes.

A Novel Mixed Hydroxide Method for Hydroxyapatite Preparation

2010 ◽  
Vol 152-153 ◽  
pp. 1399-1403 ◽  
Author(s):  
Mei Mei Zhang ◽  
Hong Shi Zhao ◽  
Hong Liu ◽  
Jian An Liu ◽  
Xiu Xiu Han ◽  
...  
Keyword(s):  
Raw Materials ◽  
Calcium Nitrate ◽  
Nano Particles ◽  
Calcium Nitrate Tetrahydrate ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Nitrate Tetrahydrate ◽  
Pure Phase ◽  
Temperature Time ◽  
Nano Size

Hydroxyapatite(HAP) nanoparticles were synthesized by a mixed hydroxide method using calcium nitrate tetrahydrate[Ca(NO3)24H2O] and phosphoric pentoxide(P2O5) as raw materials. The synthesized nanoparticles were analyzed by x-ray diffraction (XRD), infrared spectroscopy (IR) and transmission electron microscopy (TEM) methods. The effects of reaction temperature, time and concentration of reactants on the microstructure of the nano-particles have been discussed. The results show that the hydroxyapatite particles synthesized have features of uniform morphology, pure phase and well crystallized nano size. The particle size is in the range of 30-200 nm.

Sodium-Doped Hydroxyapatite Nanopowder through Sol-Gel Method: Synthesis and Characterization

2011 ◽  
Vol 694 ◽  
pp. 128-132 ◽  
Author(s):  
Erlani Pusparini ◽  
Iis Sopyan ◽  
Mohd. Hamdi ◽  
Singh Ramesh
Keyword(s):  
Sol Gel ◽  
Calcium Nitrate ◽  
Xrd Analysis ◽  
Sodium Concentration ◽  
Calcium Nitrate Tetrahydrate ◽  
X Ray Diffraction ◽  
Gel Method ◽  
Sol Gel Method ◽  
Transmission Electron ◽  
Nitrate Tetrahydrate

The nanocrystalline HA powders were produced through sol-gel method which employed calcium nitrate tetrahydrate [Ca(NO3)2.4H2O] and diammonium hydrogen phosphate [(NH4)2HPO4] as calcium and phosphorous precursors. Sodium ion (Na+) is one of the trace elements found in biological apatite and believed to have important effect in its performance. The concentrations of sodium dopant were varied from 0 mol% until 15 mol% by using sodium nitrate (NaNO3) as the source of dopant. Characterization of nanopowders was investigated by using X-ray diffraction (XRD), Fourier transform infra red (FTIR) and Transmission Electron Microscope (TEM). XRD analysis revealed that there are no other phases exist in the synthesized powder, evinced single phase of HA and a trend shows an increase of cristallinity with increase of sodium dopant concentration. While the TEM images showed evidence that the particle sizes were bigger with the increasing sodium concentration, showing the effect of sodium dopant on the densification of the powder.

Effect of Stirring and Aging Time on the Formation of β-Tricalcium Phosphate (β-TCP) Powder

2016 ◽  
Vol 840 ◽  
pp. 156-159
Author(s):  
Shah Rizal Kasim ◽  
Siti Noor Fazliah Mohd Noor ◽  
Zainal Arifin Ahmad
Keyword(s):  
Electron Microscopy ◽  
Aging Time ◽  
Tricalcium Phosphate ◽  
Calcium Nitrate ◽  
Xrd Analysis ◽  
Precipitation Method ◽  
Calcium Nitrate Tetrahydrate ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Nitrate Tetrahydrate

In this research, the effect of stirring and aging time on the formation of β-tricalcium phosphate (β-TCP) powder was studied. β-TCP powder was synthesized using calcium nitrate tetrahydrate (Ca(NO3)2.4H2O) (0.6M) and diammonium hydrogen phosphate (NH4)2HPO4) (0.4M) via wet precipitation method. The mixture was stirred with different duration (1, 3, 5 and 7 hours) then centrifuged before washed with distilled water (twice) and ethanol followed by drying in oven (80°C, 24 hours). The cake was ground to form powder. The as prepared powder was analyzed using thermo-gravimetric (TGA) to determine the suitable calcinations temperature. TGA results show that the proper calcinations temperature was 800°C. The formation of β-TCP was characterized using X-ray Diffraction (XRD) analysis. Sample with optimum formation of β-TCP phase will choose for further study on the effect of aging time (0.5, 1, 20 and 24 hours). XRD analysis confirmed that sample stirred for 7 hours and aging for 24 hours produced β-TCP as major phase. Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) proved that β-TCP powder form as agglomerated particles

scholarly journals Microstructure and properties of nano-laminated Y3Si2C2 ceramics fabricated via in situ reaction by spark plasma sintering

2021 ◽  
Vol 10 (3) ◽  
pp. 578-586
Author(s):  
Lin-Kun Shi ◽  
Xiaobing Zhou ◽  
Jian-Qing Dai ◽  
Ke Chen ◽  
Zhengren Huang ◽  
...  
Keyword(s):  
Spark Plasma Sintering ◽  
Atomic Scale ◽  
Max Phase ◽  
X Ray Diffraction ◽  
Selected Area Electron Diffraction ◽  
Plasma Sintering ◽  
Transmission Electron ◽  
Spark Plasma ◽  
Diffraction Patterns

AbstractA nano-laminated Y3Si2C2 ceramic material was successfully synthesized via an in situ reaction between YH2 and SiC using spark plasma sintering technology. A MAX phase-like ternary layered structure of Y3Si2C2 was observed at the atomic-scale by high resolution transmission electron microscopy. The lattice parameters calculated from both X-ray diffraction and selected area electron diffraction patterns are in good agreement with the reported theoretical results. The nano-laminated fracture of kink boundaries, delamination, and slipping were observed at the tip of the Vickers indents. The elastic modulus and Vickers hardness of Y3Si2C2 ceramics (with 5.5 wt% Y2O3) sintered at 1500 °C were 156 and 6.4 GPa, respectively. The corresponding values of thermal and electrical conductivity were 13.7 W·m-1·K-1 and 6.3×105 S·m-1, respectively.

Formation of a unique glass by spark plasma sintering of a zeolite

2009 ◽  
Vol 24 (10) ◽  
pp. 3241-3245 ◽  
Author(s):  
Lianjun Wang ◽  
Wan Jiang ◽  
Lidong Chen ◽  
Zhijian Shen
Keyword(s):  
Spark Plasma Sintering ◽  
Glass Sample ◽  
Room Temperature ◽  
Vickers Microhardness ◽  
Simple Approach ◽  
Electron Microscopic ◽  
Plasma Sintering ◽  
Transmission Electron ◽  
Transmission Electron Microscopic ◽  
Spark Plasma

A simple approach, order–disorder transition (ODT), has been developed to synthesize a novel glass using ZSM-5 as starting materials. In this process, the ZSM-5 powders were pressed uniaxially in a graphite die and rapidly sintered using spark plasma sintering (SPS). High-resolution transmission electron microscopic images revealed that a few crystalline zeolite fragments were still preserved locally inside the SPS consolidated sample. Vickers microhardness and fracture toughness of this as-prepared transparent glass sample at room temperature reaches 7.3 ± 0.2 GPa and 2.0 ± 0.3MPa·m1/2, respectively. It is very interesting that these novel bulk transparent glasses exhibit ultraviolet photoluminescence (PL) properties at about ∼360 nm.

Temperature Measurement of Single Levitated Microparticles Using Stokes/Anti-Stokes Raman Intensity Ratios

1994 ◽  
Vol 48 (12) ◽  
pp. 1498-1505 ◽  
Author(s):  
Scot D. Rassat ◽  
E. James Davis
Keyword(s):  
Temperature Measurement ◽  
Calcium Nitrate ◽  
Composition Analysis ◽  
Calcium Nitrate Tetrahydrate ◽  
Electrodynamic Balance ◽  
Beam Expander ◽  
Nitrate Tetrahydrate ◽  
Intensity Ratios ◽  
Anti Stokes ◽  
Heating Beam

A method has been developed to determine the temperature of single microparticles levitated in an electrodynamic balance. Particle temperatures were ascertained from the measured intensities of the Stokes and anti-Stokes Raman spectra. Temperatures near ambient were obtained for titanium dioxide and calcium nitrate microparticles with the use of a Raman-based calibration of the optical system to correct for wavelength-dependent effects. Higher temperatures were also measured with the use of a carbon dioxide infrared laser to electromagnetically heat the particle. In an effort to minimize particle instabilities caused by the heating beam, the Gaussian intensity profile of the beam was modified with an axicon beam expander to produce a doughnut-like intensity distribution. The temperature measurement technique and quantitative Raman composition analysis were applied to study dehydration of a calcium nitrate tetrahydrate particle.

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