scholarly journals Effect of Hexagonal Boron nitride Nanopowder Reinforcement and Mixing Methods on Physical and Mechanical Properties of Self-Cured PMMA for Dental Applications

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2323 ◽  
Author(s):  
Mana Alqahtani
Keyword(s):  
Mechanical Properties ◽  
Boron Nitride ◽  
Flexural Strength ◽  
Hexagonal Boron Nitride ◽  
Dental Materials ◽  
Physical And Mechanical Properties ◽  
Future Research ◽  
Infrared Spectrometry ◽  
Mixing Method

We report for the first time on the effect of biocompatible hexagonal boron nitride (h-BN) nanopowder reinforcement with different concentrations on the structural and mechanical properties of fabricated self-cured polymethyl methacrylate (PMMA) based dental materials (GC UNIFAST III). A comparison among the structural and mechanical properties between hand and ultrasonic mixing is also presented. Fabricated specimens were studied by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR), micro indentation, and flexural strength techniques. The ultrasonic mixing method provides better sample textures of the composite as compared to hand mixing. It is found that XRD and IR intensity of the peaks increases with the increase of h-BN concentration due to nanocomposite formation. The additions of h-BN nanoparticles to the acrylic resin enhanced the hardness and the flexibility values of the composites. Independently of the mixing method used, adding h-BN nanopowder relatively increases the Vickers Hardness numbers (VH) and Flexural Strength (FS) of the unmodified materials. However, using ultrasonic mixing method combined with h-BN nanopowder increases VH numbers to 300% and FS values to 550% with respect to the unmodified sample made by hand mixing. The results obtained are very encouraging and will support future research in vivo, to confirm whether PMMA loaded with h-BN nanoparticles is an improvement compared to current dental restorative materials.

Structure and properties of compact articles from high-alloyed iron powder with adding of boron nitride

2020 ◽  
pp. 39-48
Author(s):  
B. O. Bolshakov ◽  
◽  
R. F. Galiakbarov ◽  
A. M. Smyslov ◽  
◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Boron Nitride ◽  
Grain Boundary ◽  
Bending Strength ◽  
Physical And Mechanical Properties ◽  
Operating Conditions ◽  
Structure And Properties ◽  
Steam Turbines ◽  
Friction Forces ◽  
Wide Range

The results of the research of structure and properties of a composite compact from 13 Cr – 2 Мо and BN powders depending on the concentration of boron nitride are provided. It is shown that adding boron nitride in an amount of more than 2% by weight of the charge mixture leads to the formation of extended grain boundary porosity and finely dispersed BN layers in the structure, which provides a high level of wearing properties of the material. The effect of boron nitride concentration on physical and mechanical properties is determined. It was found that the introduction of a small amount of BN (up to 2 % by weight) into the compacts leads to an increase in plasticity, bending strength, and toughness by reducing the friction forces between the metal powder particles during pressing and a more complete grain boundary diffusion process during sintering. The formation of a regulated structure-phase composition of powder compacts of 13 Cr – 2 Mо – BN when the content of boron nitride changes in them allows us to provide the specified physical and mechanical properties in a wide range. The obtained results of studies of the physical and mechanical characteristics of the developed material allow us to reasonably choose the necessary composition of the powder compact for sealing structures of the flow part of steam turbines, depending on their operating conditions.

Boron nitride for modification of rubber based on isoprene elastomer

2020 ◽  
pp. 105-112
Author(s):  
K. S. Zhansakova ◽  
E. N. Eremin ◽  
G. S. Russkikh ◽  
O. V. Kropotin
Keyword(s):  
Mechanical Properties ◽  
Boron Nitride ◽  
Gradual Increase ◽  
Physical And Mechanical Properties ◽  
Curing Time ◽  
Cross Link ◽  
Start Time ◽  
Link Density ◽  
Cross Link Density ◽  
Isoprene Rubber

The work studies vulcanization characteristics of elastomers based on isoprene rubber filled with carbon black N330 and boron nitride (BN). The influence of the boron nitride (BN) concentration on technological, dynamic, physical and mechanical properties of elastomers has been researched. The application of boron nitride for producing rubber with good properties has been considered. With a gradual increase of the inert filler BN concentration up to 35%, a decrease in the curing rate by 33% and polymer cross-link density by 26% is observed. Moreover, the start time of vulcanization increases by almost 300%, the optimal curing time by 200%.

Hexagonal boron nitride nanoparticles trigger oxidative stress by modulating thiol/disulfide homeostasis

2021 ◽  
pp. 096032712110028
Author(s):  
F Kar ◽  
İ Söğüt ◽  
C Hacıoğlu ◽  
Y Göncü ◽  
H Şenturk ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Boron Nitride ◽  
Hexagonal Boron Nitride ◽  
Chemical Properties ◽  
Heart Tissue ◽  
Albino Rats ◽  
Dependent Manner ◽  
Tissue Samples ◽  
Boron Nitride Nanoparticles

Background: Hexagonal boron nitride nanoparticles (hBN NPs) are encouraging nanomaterials with unique chemical properties in medicine and biomedical fields. Until now, the optimal hBN NP’s dosage and biochemical mechanism that can be used for in vivo systems has not been fully revealed. The main aim of this article is to reveal characteristics, serum and tissue interactions and any acute cytotoxic effect of different dose of hBN NPs for the first time. Methods: hBN NPs at concentrations varying between 50–3200 µg/kg was administered by intravenous injection to Wistar albino rats (n = 80) divided into seven dosage and control groups. Blood and tissue samples were taken after 24 hours. Results: Our findings suggested that higher doses hBN NPs caused oxidative stress on the serum of rats dose-dependently. However, hBN NPs did not affect thiol/disulfide homeostasis on kidney, liver, spleen, pancreas and heart tissue of rats. Furthermore, hBN NPs increased serum disulfide formation by disrupting the thiol/disulfide balance in rats. Also, LOOH and MPO levels increased at high doses, while CAT levels decreased statistically. Conclusion: The results revealed that hBN NPs induce oxidative stress in a dose-dependent manner by modulating thiol/disulfide homeostasis in rats at higher concentrations

scholarly journals Properties of High-Strength Flowable Mortar Reinforced with Palm Fibers

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Eethar Thanon Dawood ◽  
Mahyuddin Ramli
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Physical And Mechanical Properties ◽  
High Strength ◽  
Test Results ◽  
Palm Fiber ◽  
Toughness Index ◽  
Strength And Toughness

This study was conducted to determine some physical and mechanical properties of high-strength flowable mortar reinforced with different percentages of palm fiber (0, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, and 1.6% as volumetric fractions). The density, compressive strength, flexural strength, and toughness index were tested to determine the mechanical properties of this mortar. Test results illustrate that the inclusion of this fiber reduces the density of mortar. The use of 0.6% of palm fiber increases the compressive strength and flexural strength by about 15.1%, and 16%, respectively; besides, the toughness index (I5) of the high-strength flowable mortar has been significantly enhanced by the use of 1% and more of palm fiber.

scholarly journals Mechanical properties of boron nitride sheet with randomly distributed vacancy defects

2019 ◽  
Vol 8 (1) ◽  
pp. 210-217 ◽  
Author(s):  
Yingjing Liang ◽  
Hongfa Qin ◽  
Jianzhang Huang ◽  
Sha Huan ◽  
David Hui
Keyword(s):  
Mechanical Properties ◽  
Boron Nitride ◽  
Performance Optimization ◽  
Fracture Strain ◽  
Mechanical Performance ◽  
Hexagonal Boron Nitride ◽  
Stable Configuration ◽  
Vacancy Defects ◽  
And Performance ◽  
Dynamics Simulations

Abstract Defects and temperature effects on the mechanical properties of hexagonal boron nitride sheet (h-BN) containing randomly distributed defects are investigated by molecular dynamics simulations and the reasons of the results are discussed. Results show that defect deteriorate the mechanical performance of BNNS. The mechanical properties are reduced by increasing percentage of vacancy defects including fracture strength, fracture strain and Young’s modulus. Simulations also indicate that the mechanical properties decrease with the temperature increasing. Moreover, defects affect the stable configuration at high temperature. With the percentage of defect increases the nanostructures become more and more unstable. Positions of the defect influent the mechanical properties. The higher the temperature and the percentage of defect are, the stronger the position of the randomly distributed defect affects the mechanical properties. The study provides a theoretical basis for the preparation and performance optimization of BNNSs.

Characteristics and Biocompatibility of the Hydroxyapatite Based Two Ternary Biocomposites

2016 ◽  
Vol 720 ◽  
pp. 130-140
Author(s):  
Berrak Bulut ◽  
Ziya Engin Erkmen ◽  
Eyup Sabri Kayali
Keyword(s):  
Mechanical Properties ◽  
Physical And Mechanical Properties ◽  
Secondary Phase ◽  
In Vitro Test ◽  
Compression Tests ◽  
Vitro Test ◽  
Dental Applications ◽  
The Ideal

Hydroxyapatite (HA) is a very popular bioceramic for orthopedic and dental applications. Although HA has excellent biocompatibility, its inferior mechanical properties make it unsuitable for load-bearing implant applications. Therefore, HA should be strengthened by a secondary phase for robust mechanical properties. The aim of this study was to compare the properties of HA-Al2O3 (HAC) and HA-ZrO2 (HZC) composites with the addition of 5 and 10 wt% commercial inert glass (CIG); independently. The mixture powders were pressed and then, the pellets were sintered between 1000-1300 °C for 4 hours. Microstructural characterizations were carried out using SEM + EDS and XRD, while hardness and compression tests were done to measure mechanical properties. In order to investigate the biocompatibility behavior of the samples in vitro and in vivo tests were performed. The mechanical properties of HAC composites increased with rising CIG content and increasing sintering temperature. For HZC composites, increasing CIG content caused an elevation in hardness and a decrease in compressive strength values at 1300 °C. The composites having the best physical and mechanical properties also showed improved bioactive properties at in vitro test. In this study, the ideal composite was selected as HZC5 sintered at 1200 °C depending on the microstructure, mechanical and biocompatibility properties.

Investigation on Microstructure Characteristics and Tribological Properties of Self-Lubricating Metallic Composites Based on Hexagonal Boron Nitride and Molybdenum Disulphide

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Biao Zhao ◽  
Wenfeng Ding ◽  
Guohua Jiang ◽  
Xianying Li ◽  
Jiuhua Xu
Keyword(s):  
Boron Nitride ◽  
Flexural Strength ◽  
Hexagonal Boron Nitride ◽  
Metallic Matrix ◽  
Solid Lubricants ◽  
Tribological Performance ◽  
Liquid Phase Sintering ◽  
Molybdenum Disulphide ◽  
Microstructure Characteristics ◽  
Metallic Composites

Abstract In this work, hexagonal boron nitride (hBN)- and molybdenum disulphide (MoS2)-embedded metallic composites were fabricated via liquid-phase sintering. The mechanical property and tribological performance of different samples that contain 5, 7.5, 10, 12.5, and 15 wt% solid lubricants were evaluated. Morphologies, such as micropores and ball and scratch, were characterized after the rotating sliding tests. A high lubricant concentration could adversely affect the flexural strength of as-sintered samples because of the formation and coalescences of micropores. In comparison with MoS2-containing samples under the same lubricant concentrations, the hBN-containing samples exhibited lower flexural strength and density caused by amounts of spherical small and irregular large micropores. Furthermore, the best tribological combination could be achieved in terms of the friction coefficient, wear-rate, and morphologies of balls by applying 7.5 wt% MoS2 particles in the metallic matrix.

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