“…The physical and mechanical properties of the polymers were tremendously improved upon the incorporation of a small proportion of graphene [ 23 , 25 ]. In the literature, GO-SiO 2 hybrids have been incorporated as filler into epoxy polymer matrix and demonstrated remarkable improvement in properties compared with pristine GO nano-sheets and SiO 2 nanoparticles individually [ 26 , 27 ]. Similarly, Haeri et al [ 28 ] incorporated graphene oxide nanosheets functionalized with silica nanoparticles as filler into epoxy resin.…”
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.
“…The physical and mechanical properties of the polymers were tremendously improved upon the incorporation of a small proportion of graphene [ 23 , 25 ]. In the literature, GO-SiO 2 hybrids have been incorporated as filler into epoxy polymer matrix and demonstrated remarkable improvement in properties compared with pristine GO nano-sheets and SiO 2 nanoparticles individually [ 26 , 27 ]. Similarly, Haeri et al [ 28 ] incorporated graphene oxide nanosheets functionalized with silica nanoparticles as filler into epoxy resin.…”
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.
“…Not only delamination failures, but matrix crack and fiber breakage failures are also affected by changing the bending deflection, which changes in terms of energy levels and fracture toughness. 22,23,27,34 Figure 12.Microscope views of (a) unfilled and (b) SiO 2 nanoparticle filled unfilled ± [55] 6 filament wound BFR/Epoxy composite tubes at 5 J of energy level.Figure 13.Microscope views of (a) unfilled and (b) SiO 2 nanoparticle filled unfilled ± [55] 6 filament wound BFR/Epoxy composite tubes at 10 J of energy level.Figure 14.Microscope views of (a) unfilled and (b) SiO 2 nanoparticle filled unfilled ± [55] 6 filament wound BFR/Epoxy composite tubes at 15 J of energy level.…”
Nano-microscale fracture mechanisms, which affect fracture toughness, play an important role in improving the impact characterization of fiber reinforced polymer composites. Therefore, crack behaviors are tried to be controlled with fracture mechanisms by filling nanoparticles into polymer matrix for improving impact characteristics and fracture toughness in latest studies. In this study, it was aimed to investigate the effects of SiO2 nanoparticles addition into epoxy matrix on the low velocity impact characteristics and fracture toughness in basalt fiber reinforced filament wound composite tubes. SiO2 nanoparticle of 4% wt. filled and unfilled ± [55]6 filament wound basalt fiber reinforced/epoxy composite tubes were subjected to low velocity impact tests at 5 J, 10 J, and 15 J of energy levels. It was seen that while the addition of nanoparticles were increasing the maximum impact forces in the range of about 19%–32%, displacements and absorbed energies decreased because of the increase in the bending stiffness. Charpy impact tests were performed to three different notched arc shaped specimens for determining the impact fracture toughness. SiO2 nanoparticles increased the fracture toughness by 20%–23%. It was observed that SiO2 nanoparticles delayed the formation of failures such as debonding and delamination, and reduced the fiber breakage branching in low velocity impact tests. A liquid penetrant test was used to inspect the crack formations and progressions on the impacted surfaces of all composite tubes as practical inspection for industrial applications. It was seen that microscope and SEM analysis supported the liquid penetrant inspection, which is a non-destructive testing method.
“…This equipment is fitted with Vickers pyramid diamond indenter and used to produce indentations at a load of 2.94 N for the dwell time of the 15 s. At least, five micro indentations were taken for different places in specimens for each sample. The Vickers Hardness values are calculated by using the Equation (4).…”
Section: Vickers Hardness Testmentioning
confidence: 99%
“…are majorly used in various applications such as adhesives, coatings, binder in structural materials. [4] For this reason the modification of the epoxy matrix by reinforcing with fillers and fibers to enhance their mechanical and tribological behavior is drawing the prime attention of the research community. The most of the researchers were reported that the mechanical and tribological properties of epoxy can be improved by the addition of the reinforcing materials.…”
In this work, graphene nanoplatelets have been synthesized using liquid phase exfoliation of graphite flake powder. The exfoliated graphene nanoplatelets were identified and characterized by using UV–Visible–NIR spectroscopy, High resolution transmission electron microscopy, electron diffraction, scanning electron microscopy and X‐ray diffraction. The obtained graphene nanoplatelets and nano alumina at various weight ratios were dispersed in an epoxy matrix to enhance the surface roughness (Ra), micro hardness (Hv) and coefficient of friction (CoF) of epoxy hybrid nanocomposites. The results showed that the Ra and CoF value for the combined loading of 0.2 wt% of graphene nanoplatelets and 0.8 wt% of alumina into the epoxy was decreased to 41.02 and 20.01% whereas, the Hv value was increased to 10.04% when compared with the neat epoxy. The improved mechanical and tribological behaviors are suitable for the applications bearing and coating.
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