scholarly journals Evaluation of Synergic Potential of rGO/SiO2 as Hybrid Filler for BisGMA/TEGDMA Dental Composites

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3025
Author(s):  
Ali Alrahlah ◽  
Rawaiz Khan ◽  
Abdel-Basit Al-Odayni ◽  
Waseem Sharaf Saeed ◽  
Leonel S. Bautista ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Elastic Modulus ◽  
Rheological Properties ◽  
Indentation Test ◽  
Control Group ◽  
Indentation Hardness ◽  
Hybrid Filler ◽  
Nano Indentation ◽  
Base Composite ◽  
Surface Modified

Graphene and graphene oxide based nanomaterials have attained immense significance in research because of their matchless physiochemical characteristics. Although potential biomedical applications of graphene have been extensively studied, however, dentistry related applications were rarely explored. This study aimed to investigate the effect of various percentages of surface modified reduce graphene oxide (S-rGO) in combination with SiO2 nanoparticles (bulk filler) on numerous physio-mechanical characteristics of acrylate-based (BisGMA/TEGDMA: 1:1 by wt.) composites. BisGMA/TEGDMA reinforced with 30 wt.% surface modified fumed-silica (S-A200) was considered as control group (base composite). Various concentrations (0, 0.5, 1, 2, 4 wt.%) of S-rGO were incorporated into the base composite via solution casting and high-speed mixing. The obtained composites were characterized for rheological properties before curing by using Rheometer (Anton Paar, USA) in the oscillatory mode under a frequency sweep over a range of angular frequency of 0.1–100 rad/s at 25 °C. The degree of conversion (DC) was measured by using Fourier transform infrared spectroscopy (FTIR). A Nano-indentation test was carried out to obtain nano-hardness and elastic modulus. The surface roughness was measured by optical microscope (Bruker®), 3D non-contact surface profilometer. The structural and morphological properties were studied by using Scanning Electron Microscopy (SEM). The mean and standard deviation were calculated and a simple mean comparisons test was performed for comparison using SPSS. The results revealed that the addition of a tiny proportion of S-rGO considerably increased the nano-indentation hardness, elastic modulus and DC. Conversely, a gradual reduction in viscosity was observed with increasing S-rGO concentration. The study demonstrates that a small fraction of S-rGO in combination with SiO2 could enhance physical, mechanical and rheological properties of acrylate based composites. Thus S-rGO/SiO2 combination could be used as a potential hybrid filler for dental nanocomposites.

Study of the Ion Nitrided Layer on Ti-6Al-4V Substrate

2009 ◽  
Vol 79-82 ◽  
pp. 695-698
Author(s):  
Xiu Yan Li ◽  
Jiao Rong Ye ◽  
Bin Tang
Keyword(s):  
Elastic Modulus ◽  
Titanium Alloys ◽  
Indentation Depth ◽  
Substrate Surface ◽  
Nitrided Layer ◽  
Flux Ratio ◽  
Indentation Test ◽  
Hard Coatings ◽  
Ion Nitriding ◽  
Nano Indentation

Titanium alloys are often material of choice for aerospace, chemical and biomedical industries, because of their unusual corrosion resistance, high mechanical strength and low density. However titanium alloys have very poor wear resistance. Hard coatings can be formed on the surface of titanium alloys to improve their tribological property. In this work ion nitriding without hydrogen technique was used to treat Ti-6Al-4V alloy and the nitrided layer was formed on the substrate surface. The fundamental coating properties, such as the phase, component, hardness and elastic modulus were investigated. At the ion-nitriding condition of flux ratio N2/Ar=1:1, pressure 40 pa and substrate temperature 900°C, the nitrided layer was formed. The layer consists of Ti2N and TiN compound. The content of element nitrogen in the nitrided layer gradiently decreases from the the surface to the substrate direction. For a better understanding of the hardness of the nitrided layer, the nano indentation test and microhardness test are both used. The results show that the average values of hardness and elastic modulus for the surface of the nitrided layer are 17.36GPa and 328.81GPa, about 6 times and 3 times respectively as those of Ti-6Al-4V substrate. The hardness of the nitrided layer decreases from the surface to the substrate direction, which corresponding to the content change of element nitrogen. For the result of nano indentation test, when the indentation depth is more than 400nm, the values of hardness and elastic modulus both decrease with the increase of the indentation depth. It is because of the influence of the soft Ti-6Al-4V substrate.

The Evaluation of the Elastic Property in Nano-Scaled Thin Compressive Film on Patterned Substrates

2005 ◽  
Vol 475-479 ◽  
pp. 3935-3938
Author(s):  
M.W. Moon ◽  
T.Y. Kim ◽  
Kwang Real Lee ◽  
Kyu Hwan Oh
Keyword(s):  
Elastic Modulus ◽  
Elastic Property ◽  
Indentation Test ◽  
Simple Equation ◽  
Diamond Like Carbon ◽  
Patterned Substrates ◽  
Patterned Substrate ◽  
Nano Indentation ◽  
Pattern Width

The evaluation of elastic property for thin diamond-like carbon (DLC) films has been presented with buckle analysis of compressive stressed film on patterned substrate. When substrate has been patterned with adhesion release layer, the morphologies of buckle configuration on patterned layer has been controlled from straight sided (Euler) buckle to nonlinear telephone cord type buckle with respect to the pattern width. By using the simple equation for Euler buckle, the elastic modulus has been easily calculated, shown well consistent with the results by nano-indentation test.

scholarly journals Study of Surface Mechanical Characteristics of ABS/PC Blends Using Nanoindentation

Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 637
Author(s):  
Saira Bano ◽  
Tanveer Iqbal ◽  
Naveed Ramzan ◽  
Ujala Farooq
Keyword(s):  
Elastic Modulus ◽  
Polymer Blends ◽  
Mechanical Performance ◽  
Acrylonitrile Butadiene Styrene ◽  
Maximum Load ◽  
Indentation Load ◽  
Melt Processing ◽  
Indentation Hardness ◽  
Nano Indentation ◽  
Butadiene Styrene

Acrylonitrile butadiene styrene (ABS) and polycarbonate (PC) are considered a well-known class of engineering thermoplastics due to their efficient use in automotive, 3D printing, and electronics. However, improvement in toughness, processability, and thermal stability is achieved by mixing together ABS and PC. The present study focuses on the understanding of surface mechanical characterization of acrylonitrile butadiene styrene (ABS) and polycarbonate (PC) blends using nano-indentation. Polymer blends sheets with three different proportions of ABS/PC (75:25, 50:50, and 25:75) were fabricated via melt-processing and thermal press. Fourier transform infrared (FTIR) spectroscopy was performed to analyze the intermolecular interactions between the blends’ components. To understand the surface mechanical properties of ABS and PC blends, a sufficient number of nano-indentation tests were performed at a constant loading rate to a maximum load of 100 mN. Creeping effects were observed at the end of loading and start of unloading section. Elastic modulus, indentation hardness, and creep values were measured as a function of penetration displacement in the quasi-continuous stiffness mode (QCSM) indentation. Load-displacement curves indicated an increase in the displacement with the increase in ABS contents while a decreasing trend was observed in the hardness and elastic modulus values as the ABS content was increased. We believe this study would provide an effective pathway for developing new polymer blends with enhanced mechanical performance.

scholarly journals Assessment of Graphene Oxide and Nanoclay Based Hybrid Filler in Chlorobutyl-Natural Rubber Blend for Advanced Gas Barrier Applications

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1098
Author(s):  
Jibin Keloth Paduvilan ◽  
Prajitha Velayudhan ◽  
Ashin Amanulla ◽  
Hanna Joseph Maria ◽  
Allisson Saiter-Fourcin ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Carbon Black ◽  
Natural Rubber ◽  
Gas Permeability ◽  
Chemical Properties ◽  
Barrier Properties ◽  
Hybrid Filler ◽  
Physical And Chemical ◽  
Chlorobutyl Rubber ◽  
And Chemical Properties

Nanomaterials have engaged response from the scientific world in recent decades due to their exceptional physical and chemical properties counter to their bulk. They have been widely used in a polymer matrix to improve mechanical, thermal, barrier, electronic and chemical properties. In rubber nanocomposites, nanofillers dispersion and the interfacial adhesion between polymer and fillers influences the composites factual properties. In the present work, a comparison of the hybrid effects of carbon black with two different nanofillers (graphene oxide and nanoclay) was studied. The 70/30 composition of chlorobutyl rubber/natural rubber elastomer blend was taken as per the blend composition optimized from our previous studies. The hybrid effects of graphene oxide and nanoclay in dispersing the nanofillers were studied mainly by analyzing nanocomposite barrier properties. The results confirm that the combined effect of carbon black with graphene oxide and nanoclay could create hybrid effects in decreasing the gas permeability. The prepared nanocomposites which partially replace the expensive chlorobutyl rubber can be used for tyre inner liner application. Additionally, the reduction in the amount of carbon black in the nanocomposite can be an added advantage of considering the environmental and economic factors.

Elastic Modulus of Pb/Sn Solder Joints in Microelectronics

2002 ◽  
Author(s):  
Cemal Basaran ◽  
Jianbin Jiang
Keyword(s):  
Grain Size ◽  
Elastic Modulus ◽  
Single Crystal ◽  
Solder Alloy ◽  
Ultrasonic Testing ◽  
Heterogeneous Materials ◽  
Testing Methods ◽  
Nano Indentation ◽  
Deformation Kinetics ◽  
Kinetics Of

Young’s modulus (E) values published in literature for the eutectic Pb37/Sn63 and near eutectic Pb40/Sn60 solder alloy vary significantly. One reason for this discrepancy is different testing methods for highly rate sensitive heterogeneous materials, like Pb/Sn alloys, yield different results. In this paper, we study different procedures used to obtain the elastic modulus; analytically, by single crystal elasticity and experimentally by ultrasonic testing and Nano indentation. We compare these procedures and propose a procedure for elastic modulus determination. The deformation kinetics of the Pb/Sn solder alloys is discussed at the grain size level.

Effects of polymer binder on rheological properties of silver pastes for screen printing front electrode films of solar cells

2015 ◽  
Vol 29 (10n11) ◽  
pp. 1540027 ◽  
Author(s):  
Jun Qin ◽  
Weijun Zhang ◽  
Zhuofeng Liu ◽  
Shuxin Bai
Keyword(s):  
Solar Cells ◽  
Rheological Properties ◽  
Screen Printing ◽  
Model Parameters ◽  
Silver Particles ◽  
Front Electrode ◽  
Strength Of Interaction ◽  
Fundamental Understanding ◽  
Surface Modified ◽  
Down Sweep

The purpose of the study is to characterize and improve the fundamental understanding of the effects of Ethyl Cellulose (EC) binder on the rheological properties of silver pastes for screen printing front electrode films of solar cells. Dispersions of silver particles (surface modified with oleic acid) in EC polymer solutions with and without thixotropic agent were prepared; and yield stress values were measured by setting shear stress to characterize the strength of interaction in pastes. Week flocculation network of silver particles is produced due to depletion of flocculation. EC polymer also has a significant interaction with thixotropic agent. Down-sweep flow curves of dispersions without thixotropic agent were measured and well fitted by Generalized Casson model. The model parameters p indicated that EC polymer with high molecular weight has a stronger shear-thinning ability. Steady-state flow, three interval thixotropy shear test (3ITT) and oscillatory measurements were conducted to study the effect of EC content on viscosity, structure rebuilding and viscoelastic properties of electrode pastes. Increasing EC polymer is not the best way to prevent the layer printed from laying down.

Impact of Surface-Modified Nanoparticles on Glass Transition Temperature and Elastic Modulus of Polymer Thin Films

2007 ◽  
Vol 40 (22) ◽  
pp. 7755-7757 ◽  
Author(s):  
Jong-Young Lee ◽  
Kristin E. Su ◽  
Edwin P. Chan ◽  
Qingling Zhang ◽  
Todd Emrick ◽  
...  
Keyword(s):  
Thin Films ◽  
Glass Transition ◽  
Elastic Modulus ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Polymer Thin Films ◽  
Surface Modified ◽  
Surface Modified Nanoparticles

scholarly journals Analysis of depth-sensing indentation tests with a Knoop indenter

2001 ◽  
Vol 16 (6) ◽  
pp. 1660-1667 ◽  
Author(s):  
L. Riester ◽  
T. J. Bell ◽  
A. C. Fischer-Cripps
Keyword(s):  
Elastic Modulus ◽  
Elastic Recovery ◽  
Indentation Test ◽  
New Method ◽  
Short Axis ◽  
Depth Sensing ◽  
Specimen Material ◽  
Indentation Tests ◽  
Conventional Methods ◽  
Knoop Indenter

The present work shows how data obtained in a depth-sensing indentation test using a Knoop indenter may be analyzed to provide elastic modulus and hardness of the specimen material. The method takes into account the elastic recovery along the direction of the short axis of the residual impression as the indenter is removed. If elastic recovery is not accounted for, the elastic modulus and hardness are overestimated by an amount that depends on the ratio of E/H of the specimen material. The new method of analysis expresses the elastic recovery of the short diagonal of the residual impression into an equivalent face angle for one side of the Knoop indenter. Conventional methods of analysis using this corrected angle provide results for modulus and hardness that are consistent with those obtained with other types of indenters.

Measurement of Young's Modulus and Poisson's Ratio of Thin Film by Combination of Bulge Test and Nano-Indentation

2008 ◽  
Vol 33-37 ◽  
pp. 969-974 ◽  
Author(s):  
Bong Bu Jung ◽  
Seong Hyun Ko ◽  
Hun Kee Lee ◽  
Hyun Chul Park
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Young’S Modulus ◽  
Poisson’S Ratio ◽  
Young's Modulus ◽  
Applied Pressure ◽  
Indentation Test ◽  
Poisson's Ratio ◽  
Bulge Test ◽  
Nano Indentation

This paper will discuss two different techniques to measure mechanical properties of thin film, bulge test and nano-indentation test. In the bulge test, uniform pressure applies to one side of thin film. Measurement of the membrane deflection as a function of the applied pressure allows one to determine the mechanical properties such as the elastic modulus and the residual stress. Nano-indentation measurements are accomplished by pushing the indenter tip into a sample and then withdrawing it, recording the force required as a function of position. . In this study, modified King’s model can be used to estimate the mechanical properties of the thin film in order to avoid the effect of substrates. Both techniques can be used to determine Young’s modulus or Poisson’s ratio, but in both cases knowledge of the other variables is needed. However, the mathematical relationship between the modulus and Poisson's ratio is different for the two experimental techniques. Hence, achieving agreement between the techniques means that the modulus and Poisson’s ratio and Young’s modulus of thin films can be determined with no a priori knowledge of either.

Modelling the nano indentation behaviour of recast layer and heat affected zone on reverse micro EDMed hemispherical feature

2021 ◽  
pp. 1-15
Author(s):  
Tribeni Roy ◽  
Anuj Sharma ◽  
Prabhat Ranjan ◽  
R. Balasubramaniam
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Heat Affected Zone ◽  
Parent Material ◽  
Recast Layer ◽  
Machined Surface ◽  
Nano Indentation ◽  
Fea Simulation ◽  
Load Displacement ◽  
Good Agreement

Abstract Electrical discharge machined surfaces inherently possess recast layer on the surface with heat affected zone (HAZ) beneath it and these have a detrimental effect on the mechanical properties viz. hardness, elastic modulus, etc. It is very difficult to experimentally characterise each machined surface. Therefore, an attempt is made in this study to numerically calculate the mechanical properties of the parent material, HAZ and the recast layer on a hemispherical protruded micro feature fabricated by reverse micro EDM (RMEDM). In the 1st stage, nano indentation was performed to experimentally determine the load-displacement plots, elastic modulus and hardness of the parent material, HAZ and the recast layer. In the 2nd stage, FEA simulation was carried out to mimic the nano indentation process and determine the load-displacement plots for all the three cases viz. parent material, recast layer and HAZ. Results demonstrated that the load'displacement plots obtained from numerical model in each case was in good agreement with that of the experimental curves. Based on simulated load-displacement plots, hardness was also calculated for parent material, HAZ and the recast layer. A maximum of 11% error was observed between simulated values of hardness and experimentally determined values.

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