scholarly journals Effect of Low Hydroxyapatite Loading Fraction on the Mechanical and Tribological Characteristics of Poly(Methyl Methacrylate) Nanocomposites for Dentures

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 857
Author(s):  
Ahmed Fouly ◽  
Ahmed Mohamed Mahmoud Ibrahim ◽  
El-Sayed M. Sherif ◽  
Ahmed M.R. FathEl-Bab ◽  
A.H. Badran
Keyword(s):  
Friction Coefficient ◽  
Yield Strength ◽  
Methyl Methacrylate ◽  
Weight Fraction ◽  
Tribological Characteristics ◽  
Compressive Yield Strength ◽  
Wear Loss ◽  
Mechanical Mixing ◽  
Poly Methyl Methacrylate ◽  
Mechanical And Tribological Characteristics

Denture base materials need appropriate mechanical and tribological characteristics to endure different stresses inside the mouth. This study investigates the properties of poly(methyl methacrylate) (PMMA) reinforced with different low loading fractions (0, 0.2, 0.4, 0.6, and 0.8 wt.%) of hydroxyapatite (HA) nanoparticles. HA nanoparticles with different loading fractions are homogenously dispersed in the PMMA matrix through mechanical mixing. The resulting density, Compressive Young’s modulus, compressive yield strength, ductility, fracture toughness, and hardness were evaluated experimentally; the friction coefficient and wear were estimated by rubbing the PMMA/HA nanocomposites against stainless steel and PMMA counterparts. A finite element model was built to determine the wear layer thickness and the stress distribution along the nanocomposite surfaces during the friction process. In addition, the wear mechanisms were elucidated via scanning electron microscopy. The results indicate that increasing the concentration of HA nanoparticles increases the stiffness, compressive yield strength, toughness, ductility, and hardness of the PMMA nanocomposite. Moreover, tribological tests show that increasing the nanoparticle weight fraction considerably decreases the friction coefficient and wear loss.

scholarly journals STUDY THERMAL BEHAVIOR OF HEAT CURE POLY (METHYL METHACRYLATE) REINFORCED BY BAMBOO AND RICE HUSK POWDERS FOR DENTURE APPLICATIONS

2019 ◽  
Vol 11 (4) ◽  
pp. 417-425
Author(s):  
Jawad K. Oleiwi ◽  
Qahtan Adnan Hamad ◽  
Hadil Jabbar Abdul Rahman
Keyword(s):  
Thermal Conductivity ◽  
Thermal Diffusivity ◽  
Methyl Methacrylate ◽  
Thermal Behavior ◽  
Rice Husk ◽  
Weight Fraction ◽  
Scanning Calorimetry ◽  
Poly Methyl Methacrylate ◽  
Heat Cure ◽  
Naoh Solution

The present research, studies the effect of adding two different types of reinforcing powders, which included: Bamboo (Ba) and Rice Husk (RH), that added with different weight fractions (2, 4, 6 and 8 wt. %), and with the selected size particles of (25µm and 75µm) on thermal behavior of heat Cure Poly (Methyl Methacrylate) such as thermal conductivity and thermal diffusivity in addition to the differential scanning calorimetry (DSC) analysis  and these tests were accomplished at temperature of laboratory. The poly Methyl Methacrylate properties which reinforced by (Bamboo and Rice Husk) powders are mainly influenced by the interfacial adhesion strength between the powders and the matrix, and in order to get better correlation between the natural powder and PMMA matrix, so the powders were treated with alkali (sodium hydroxide NaoH) solution prior to use as reinforcement materials. The results showed that the values of the thermal conductivity and thermal diffusivity increased with increasing of the weight fraction for both particle sizes (25 µm and 75 µm) of natural powders.

Analysis of Wear, Tensile and Thermal Properties of Poly Methyl Methacrylate Filled with Licorice Particle and Pomegranate Peels

2020 ◽  
Vol 38 (10A) ◽  
pp. 1539-1557
Author(s):  
Reem A. Mohammed ◽  
Marwah S. Attallah
Keyword(s):  
Thermal Properties ◽  
Methyl Methacrylate ◽  
Wear Behavior ◽  
Weight Fraction ◽  
Mean Value ◽  
Pomegranate Peel ◽  
Thermal Tests ◽  
Elongation At Break ◽  
Poly Methyl Methacrylate ◽  
Pin On Disk

In the present work, analysis of wear behavior, tensile and thermal properties have been done for two sets Poly Methyl Methacrylate samples which is reinforced through licorice particles and pomegranate peels particles. Wear rate resistance is evaluated based on Taguchi’s experimental design L9 (MINITAB 18) under the three factors: weight fraction of fillers (1%, 2%, 3%, 4% and 5% wt.) sliding time (5, 8 and 11 min) and load applied (10, 15and 20N) using a pin-on-disk device. Results display that the samples (Poly Methyl Methacrylate +5% licorice particles and 5% pomegranate peels particles) show the best resistance wear of (0.045×10-6 and 0.10×10-6) respectively. Signal to noise (S/N) results showed that 5% weight fraction (licorice particles and pomegranate particles with PMMA), 11 minutes (sliding time) and 15N (applied load) give the best resistance wear. Statistical analysis of tensile and thermal tests, exhibit that the best mean value of the tensile strength, modulus of elasticity, thermal conductivity, and thermal diffusivity are (±73 MPa, ±70 MPa, ±4.800 GPa, ±4.300 GPa, ±.5600 W/m k, ±.5400 W/m k, ±.3800 mm2/sec, ±.2800 mm2/sec) respectively, of the samples (PMMA+5% licorice particles and 5% pomegranate peel particles). While that the best mean value of the elongation at break (±3.600%, ±3.500%) respectively, of the samples (PMMA + 1% licorice particles and 1% pomegranate peel particles). The results showed that the addition of licorice and pomegranate particles to poly methyl methacrylate resin has improved the properties of wear, tensile and thermal properties.

Enhancing the wear resistance of WC–Co cutting inserts using synthetic diamond coatings

2018 ◽  
Vol 70 (7) ◽  
pp. 1224-1233 ◽  
Author(s):  
Kaleem Ahmad Najar ◽  
N.A. Sheikh ◽  
Mohammad Mursaleen Butt ◽  
M.A. Shah
Keyword(s):  
Friction Coefficient ◽  
Tribological Properties ◽  
Synthetic Diamond ◽  
Cutting Tools ◽  
Tribological Characteristics ◽  
Diamond Coating ◽  
Diamond Coatings ◽  
Content Type ◽  
Mechanical And Tribological Properties ◽  
Mechanical And Tribological Characteristics

Purpose The purpose of this study is to investigate the mechanical and tribological properties of the synthetic diamond coatings deposited on WC-Co cutting tools for their prospective applications in mechanical industry. In this work, the concept of nanocrystalline diamond, microcrystalline diamond and multilayer-diamond coating systems were proposed and deposited on WC-Co substrates with the top-layer nanocrystallinity, optimum thickness and interfacial adhesion strength for load-bearing tribological and machining applications. Also, the overall mechanical and tribological properties of all synthetic diamond coatings were compared for the purpose of selecting a suitable type of protective layer used on the surfaces of WC-Co cutting tools or mechanical dies. Design/methodology/approach Smooth and adhesive single layered and multilayered synthetic deposited on chemically etched cemented tungsten carbide (WC-Co) substrates using predetermined process parameters in hot filament chemical vapor deposition (HFCVD) method. A comparison has been documented between diamond coatings having different nature and architecture for the purpose of studying their mechanical and tribological characteristics. The friction characteristics were studied experimentally using ball-on-disc type linear reciprocating micro-tribometer under the influence of varying load conditions and within dry sliding conditions. Nanoindentation tests were conducted on each diamond coating using Berkovich nanoindenter for the measurement of their hardness and elastic modulus values. Also, the wear characteristics of all sliding bodies were studied under varying load conditions using cumulative weight loss and density method. Findings Depositing any type of diamond coating on the cemented carbide tool insert increases its all mechanical and tribological characteristics. When using boron-doping onto the top-layer surface of diamond coatings decrease slightly their mechanical properties but increases the tribological characteristics. Present analysis reveals that friction coefficient of all diamond-coated WC-Co substrates decreases with the increase of normal load. Therefore, maintaining an appropriate level of normal load, sliding time, sliding distance, atmospheric conditions and type of diamond coating, the friction coefficient may be kept to some lower value to improve mechanical processes. Originality/value As the single layered synthetic diamond coatings have not given the full requirements of mechanical and tribological properties when deposited on cutting tools. Therefore, the multilayered diamond coatings were proposed and developed to enhance the interfacial integrity of the nanocrystalline and microcrystalline layers (by eliminating the sharp interface) as well as increasing the hardness of tungsten carbide substrate. However, when using boron doping onto the top-layer surface of diamond, coatings decreases slightly their mechanical characteristics but also decreases the value of friction coefficient.

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