Addition Of nano-SiO2 Particles Research Articles

Characterization of hydrophobic epoxy soybean oil-based rigid plastic reinforced with nano SiO2 particles

The study involved the production of rigid plastics by crosslinking vanillin-hexanediamine (VH) with epoxidized soybean oil (ESO) through an open ring reaction, resulting in the formation of VHE resin. Various proportions of nano SiO2 particles were added to the VHE resin in order to produce hydrophobic rigid plastics derived from renewable sources. This study evaluated the impact of different mass ratios of nanoparticles to VHE resin (1:10, 1:5, 3:10) on the performance of the resulting plastics. FTIR and 13C NMR analysis have verified that VH has effectively undergone crosslinking with ESO, leading to the formation of VHE with a uniformly smooth surface that is free from pores and cracks. The introduction of nano SiO2 particles enhances the surface roughness and surface energy of the VHES plastics, resulting in hydrophobic properties, as evidenced by their high water contact angles. The addition of nano SiO2 particles improved the resistance of the VHES plastics to degradation caused by light, heat, and electricity. Nevertheless, the improvement is constrained to a maximum ratio of 1.5 (VHES2) and diminishes as the ratio of SiO2 particles increases (3:10). Furthermore, VHES2 samples demonstrated commendable biodegradability in addition to their previously mentioned exceptional properties. The study's findings suggest that vanillin and vegetable oil can be used to create biodegradable, hydrophobic plastic.

Effects of nano-SiO2 particle addition on the structure and properties of micro-arc oxidation ceramic coatings on 7075 aluminum alloy

PurposeThe purpose of this study is to investigate the influence of varying concentrations of nano-SiO2 particle doping on the structure and properties of the micro-arc oxidation (MAO) coating of 7075 aluminum alloy. This research aims to provide novel insights and methodologies for the surface treatment and protection of 7075 aluminum alloy.Design/methodology/approachThe surface morphology of the MAO coating was characterized using scanning electron microscope. Energy spectrometer was used to characterize the elemental content and distribution on the surface and cross section of the MAO coating. The phase composition of the MAO coating was characterized using X-ray diffractometer. The corrosion resistance of the MAO coating was characterized using an electrochemical workstation.FindingsThe results showed that when the addition of nano-SiO2 particles is 3 g/L, the corrosion resistance is optimal.Originality/valueThis study investigated the influence of different concentrations of nano-SiO2 particles on the structure and properties of the MAO coating of 7075 aluminum alloy.

Effect of melting temperatures on the orientation and rheology of polyacrylate/silica (PAcr/SiO2) composite microspheres in twin‐screw extruder

AbstractThe dispersion and orientation arrangement of functional polymers with fillers are critical to their performance. However, there are rare detailed researches on the visualization of the orientation process about functional fillers in composite melts and the mechanistic effects on performance. In this work, it explored the change process of the orientation morphology for polyacrylate/silica (PAcr/SiO2) composite microspheres in polymethyl methacrylate (PMMA) at different melting temperatures. Afterwards, the morphology and distribution of oriented microfibers in composite fibers melted at different temperatures were observed by transmission electron microscope (TEM). The results showed that composite microfibers could be formed in tight arrangement and obtained average orientation of 50.88 in the composite fibers at 250°C. Under this circumstance, the addition of nano SiO2 particles had no effect on the rheological type. Meanwhile, the shear stress was 99.29% higher than that of pure PMMA system under the same conditions. As for the elongation at break, it was found that the elongation at break of the composite fiber prepared at 250°C was 169.43% higher than that of pure PMMA. Therefore, it provided a new method to achieve well dispersion of functional fillers in molten systems. Furthermore, it was beneficial to enhance the elongation at break of functional composites.

Effect of different contents of nano-SiO2 particles on water diffusion behavior in insulating oil

As an important component of the internal insulation system in a transformer, insulating oil will gradually age during the long-term operation of the transformer, which will lead to a degradation of its insulation performance. Previous studies have demonstrated that the addition of nano-SiO2 particles can effectively improve the breakdown voltage of insulating oil. Nano-SiO2 can effectively restrain the movement of water molecules in oil, which is one of the important reasons for nano-SiO2 particles to increase the breakdown voltage. The diffusion behaviors associated with different water contents in insulating oils with different nanoparticle contents are discussed herein, and the mechanisms at work in nano-SiO2 modified insulating oils are described on the molecular level. In this paper, simulations were based on naphthenic mineral oil, according to the mass ratio of the alkanes, which can fully represent the main physical and chemical properties of the insulating oil were employed in building the model, the mass-based percentages of water in the models were 1%, 3% and 5%, within each group, the models included an oil/water mixture containing nano-SiO2 which the mass-based percentages of nano were 1%, 2%, 3%, 4%, 5%. Prior to molecular dynamics simulations, the model was geometrically optimized, after which it was annealed and again geometrically optimized. Those systems that achieved equilibrium and energy convergence after this process could be employed for the molecular dynamics simulation. Through the analysis of the experimental results, the optimal concentration of nano-SiO2 particles for moisture binding in insulating oil was studied from a microscopic point of view. These results should assist in providing a theoretical foundation for further research regarding nano-modified insulating oils. In engineering applications, the content of nanometer SiO2 particles can be changed according to the moisture content at different times in the oil, so as to achieve the optimal binding of water, thus keeping the insulating oil with the best electrical performance.

The Effect and Associate Mechanism of Nano SiO₂ Particles on the Diffusion Behavior of Water in Insulating Oil.

Moisture has a significant effect on the internal insulation performance of transformers, and is closely related to the breakdown voltage of transformer insulating oil. In the present work, we studied the effect of nano-SiO2 particles on the diffusion of water in insulating naphthenic mineral oil using molecular dynamics simulation. Six models were established, three of which contained nano-SiO2 particles together with water concentration of 1 wt.%, 2 wt.%, or 3 wt.%. For each model variations in free volume, mean square displacement, and interaction energy were assessed. The addition of nano SiO2 particles was found to reduce the free volume fraction of the model and as well as the free motion of water molecules in the oil. These particles also increased the interaction between the oil and water molecules, indicating that insulating oil containing nano-particles has a greater binding effect on water. The diffusion coefficient of water in oil containing nano-SiO2 particles was reduced, such that water molecules were less likely to diffuse. The results also show that these particles adsorb water molecules in the oil and to reduce diffusion. Consequently, the addition nano-scale SiO2 particles could potentially improve the breakdown voltage of the insulating oil.

Enhancing structure integrity and corrosion resistance of Mg alloy by a two-step deposition to avoid F ions etching to nano-SiO2 reinforcement

Abstract The enhancement of corrosion resistance depends heavily on functionalization of surface coating during plating. The addition of nano-SiO2 particles (NSPs) into electroless nickel plating (ENP) bath provides a possibility to produce functionalized coatings with a wider range of compositions for enhancing corrosion resistance. This report describes a new approach to functionalization of the coating on Mg alloy by using duplex-layers with NSPs incorporated in the outer layer. The effect of the NSPs on the microstructure, composition and corrosion resistance of the coatings was investigated by an array of analytical techniques, including scanning electron microscope (SEM), energy dispersive spectrometry (EDS), and X-ray diffraction (XRD), and potentiodynamic polarization (PDP) measurement. The results show that the incorporation of NSPs produces a more uniform and smoother coating surface compared with the coating that without NSPs. The corrosion resistance of the new prepared coating is better than that of single coating, which also depends on detailed preparation methods. An optimum concentration of NSPs in the plating bath for the highest enhancement in corrosion resistance in aggressive NaCl and HCl mediums has been identified. The mechanism of how the NSPs influence the corrosion resistance is also discussed.

Characteristic analysis of surface damage and bulk micro-cracks of SiR/SiO2nanocomposites caused by surface arc discharges

Anti-pollution flashover coating made by room temperature vulcanized (RTV) silicone rubber (SiR) has been widely used in electrical equipment insulation. However, it faces many outstanding problems; for example, the erosion caused by surface arc discharges. This paper presents the characteristic analysis on surface damage and bulk microcracks of SiR/SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> nanocomposites caused by surface arc discharges in order to better understand the suppression mechanism of nano-SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> particles. The specimens were prepared by adding nano-sized SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> particles into neat RTV SiR with different weight ratio and the experiments were performed according to IEC 60587. During the experiments, a high-speed camera was used to record the discharge processes. After the experiments, the eroded parts of each specimen were dyed by methylene blue solution. Also, a high-power microscope was used to observe the bulk micro-cracks. Then, an image processing technology was used for processing the surface damage images, bulk cracks images, and discharge light images to analyze the effects of adding nano fillers in SiR. The results show that as the content of nano-SiO2 fillers increases, the distribution ranges of black solid residues and dry-band traces caused by surface arc discharges tend to decrease. It indicates the increasing resistance to surface damage. Moreover, the depth of bulk micro-cracks and their area ratio show a decreasing tendency. It reveals the decreasing propagation of bulk micro-cracks. In addition, the reducing total luminance of discharge light shows the decrease of discharge intensity. Therefore, at the certain weight ratios, the addition of nano-SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> particles can not only improves the resistance to surface damage, but also inhibits the propagation of micro-cracks tracking in SiR bulk.

Double Sealing of Ultrasonic Micro-Arc Oxidation Coating on Pure Magnesium by Nano-SiO&lt;sub&gt;2&lt;/sub&gt; Particles and SiO&lt;sub&gt;2&lt;/sub&gt; Sol Sealing Agent

A double sealing coating was prepared on ultrasonic micro-arc oxidized pure magnesium substrate by adding nano-SiO2 particles as additive in the plating solution and coating SiO2 sol as sealing agent. The bonding characters of SiO2 sol was analyzed by Fourier transformed infrared spectrometry (FTIR). The compositions and morphology of seal coating were characterized by energy-dispersive X-ray spectroscopy (EDS) and scanning electron microscopy (SEM), respectively. The corrosion resistance of the micro-arc oxidized and the sealed pure magnesium substrate were studied. The results showed that the Si content increased gradually with the addition of nano-SiO2 particles and the SiO2 sol sealing. It was benefit to create bioactive MgSiO3, which promoted the bone growth. The double sealed pure magnesium had a self-corrosion potential shifted positively by 60mV as well as a self-corrosion current density decreased by a half in a 3.5wt% NaCl solution, showing good corrosion resistance.

Study on the Morphological and Mechanical Properties of Nylon 6/ABS/Nano-SiO2 Composites

The mechanical properties and morphology of the composites of nylon 6, acrylonitrile-butadiene-styrene (ABS) rubber, and nano-SiO2 particles were examined as a function of the nano-SiO2 content. A mixture with separation and encapsulation microstructures existed in the nylon 6/ABS/nano-SiO2 at lower nano-SiO2 content, and ABS and nano-SiO2 improved the toughness synergistically, while obvious agglomeration appeared at higher nano-SiO2 content and the impact strength decreased. Moreover, the addition of nano-SiO2 particles also affected the dispersion of the rubber phase, resulting in the appearance of smaller rubber particles. The deformation and toughening mechanisms of the composites were also investigated; they resulted from rubber voiding, crack forking, and plastic deformation of the matrix.