Pressureless sintering and mechanical properties of hydroxyapatite/functionalized multi-walled carbon nanotube composite

Abden, M.J.; Afroze, Jannatul Dil; Alam, Mohammad Saiful; Bahadur, Newaz Mohammed

doi:10.1016/j.msec.2016.05.018

Cited by 22 publications

(8 citation statements)

References 41 publications

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“…1(a) . Three characteristic reflections at 2θ = 26°, 43°, and 54° corresponding to the Bragg reflections (002), (100), and (004) were observed, which is consistent with literature reports 29 30 . After oxidation, the characteristic reflections of the OCNTs are identical to those reported for CNT samples, suggesting the long–range structure of the CNTs has not changed as a result of oxidation.…”

Section: Resultssupporting

confidence: 91%

Layered double hydroxide-oxidized carbon nanotube hybrids as highly efficient flame retardant nanofillers for polypropylene

Gao

Zhang

Williams

et al. 2016

Sci Rep

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Aqueous miscible organic layered double hydroxides (AMO-LDHs) can act as organophilic inorganic flame retardant nanofillers for unmodified non-polar polymers. In this contribution, AMO [Mg3Al(OH)8](CO3)0.5·yH2O LDH–oxidized carbon nanotube (AMO-LDH–OCNT) hybrids are shown to perform better than the equivalent pure AMO-LDH. A synergistic effect between the AMO-LDH and OCNT was observed; this endows the hybrid material with enhanced flame retardancy, thermal stability, and mechanical properties. The thermal stability of polypropylene (PP) was significantly enhanced by adding AMO-LDH–OCNT hybrids. For PP mixed with AMO-LDH–OCNT hybrids to produce a composite with 10 wt% LDH and 2 wt% OCNT, the 50% weight loss temperature was increased by 43 °C. Further, a system with 10 wt% of AMO-LDH and 1 wt% OCNT showed a peak heat release rate (PHRR) reduction of 40%, greater than the PHRR reduction with PP/20 wt% AMO-LDH (31%). The degree of dispersion (mixability) between AMO-LDH and OCNT has a significant effect on the flame retardant performance of the hybrids. In addition, the incorporation of AMO-LDH–OCNT hybrids led to better mechanical properties, such as higher tensile strength (27.5 MPa) and elongation at break (17.9%), than those composites containing only AMO-LDH (25.6 MPa and 7.5%, respectively).

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Section: Resultssupporting

confidence: 91%

Layered double hydroxide-oxidized carbon nanotube hybrids as highly efficient flame retardant nanofillers for polypropylene

Gao

Zhang

Williams

et al. 2016

Sci Rep

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“…However, to eliminate mechanical weaknesses, researchers have used different reinforcing materials. Among the materials used, carbon nanomaterials such as carbon nanotubes (CNTs), graphene, graphene oxide, and graphene nanoribbons (GNRs) have received more attention than others [30][31][32]. The most important reason is the biocompatibility and high mechanical properties of these materials.…”

Section: Introductionmentioning

confidence: 99%

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

Nosrati

Sarraf-Mamoory

Ahmadi

et al. 2020

JNT

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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.

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“…But this improvement is not enough for applications as implants, and the mechanical properties of HA still need to be increased by adding a reinforcement phase 16,17 . Of all the materials used, carbon nanomaterials such as nanotubes 18,19 and graphene 20 have recently received much attention and among the carbon materials, graphene and its derivatives have gained more research because of their unique properties. Graphene has a honeycomb-like structure.…”

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confidence: 99%

Improving the mechanical behavior of reduced graphene oxide/hydroxyapatite nanocomposites using gas injection into powders synthesis autoclave

Nosrati

Sarraf-Mamoory

et al. 2020

Sci Rep

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in this study, we show the synthesis of reduced graphene oxide/hydroxyapatite (rGo/HA) composites using a hydrothermal autoclave with argon-15% hydrogen gas injection. This both increases the hydrothermal pressure and uses hydrogen as a reductive agent in the process. The synthesized powders were then consolidated with spark plasma sintering method. The analysis of the consolidated samples included Vickers Indentation technique and cell viability. The results showed that injected gases in the autoclave produced powders with a higher crystallinity compared to synthesis without the gases. Also, hydrogen gas led to increased reduction of GO. The microscopic analysis confirmed existing graphene sheets with folding and wrinkling in the powders and indicated that various preferential directions played a role in the growth of hydroxyapatite crystals. The results showed that in general, graphene sheets increased the mechanical properties of HA. In the samples synthesized with injected gases, this increase was more significant. Interface analysis results indicate that reduced graphene oxide (rGO)/HA interface is likely coherent. These nanocomposites were biocompatible and showed some hydrophobicity compared to pure HA.

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Pressureless sintering and mechanical properties of hydroxyapatite/functionalized multi-walled carbon nanotube composite

Cited by 22 publications

References 41 publications

Layered double hydroxide-oxidized carbon nanotube hybrids as highly efficient flame retardant nanofillers for polypropylene

Layered double hydroxide-oxidized carbon nanotube hybrids as highly efficient flame retardant nanofillers for polypropylene

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

Improving the mechanical behavior of reduced graphene oxide/hydroxyapatite nanocomposites using gas injection into powders synthesis autoclave

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