scholarly journals Nanoscale Functional Additives Application in the Low Temperature Greases

Polymers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3749
Author(s):  
Sergey A. Shuvalov ◽  
Yaroslav V. Porfiryev ◽  
Dmitry S. Kolybelsky ◽  
Vladimir A. Zaychenko ◽  
Pavel S. Popov ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Low Temperature ◽  
Silicon Dioxide ◽  
Colloidal Stability ◽  
Plastic Material ◽  
Physicochemical Characteristics ◽  
Calcium Borate ◽  
Wear Properties ◽  
Dispersion Phase ◽  
Functional Additives

Due to the fact that the application of AW and EP additives in low-temperature greases may lead to worse high-temperature and anti-corrosion characteristics as well as additional burden on the environment due to the content of aggressive components, in this paper, the possibility of replacing these additives with NFA, which do not have these disadvantages, was investigated. The analysis of nanosized particles being used as functional additives in greases was carried out. The morphology of the following nanoparticles was studied: montmorillonite K 10, silica, calcium car-bonate and borate, halloysite, and molybdenum disulfide incorporated in halloysite tubes. The effect of nanostructured components on the physicochemical characteristics and anti-wear and anti-scuffing properties of complex lithium, polyurea, and polymer greases were studied. Maximal improvement of anti-wear and anti-scuffing characteristics of cLi-greases was reached when using silica and calcium borate. Maximal improvement of anti-scuffing properties of PU-lubricant was reached when using calcium carbonate and the two-component NFA based on halloysite, for anti-wear properties when adding silicon dioxide and halloysite. When the concentrations of silicon dioxide and calcium carbonate was increased from 1 to 3 wt.%, there was a decrease in yield stress of the structural frame of the PU-lubricant and its colloidal stability was worse. The increase of the concentration of calcium carbonate and borate nanoparticles in the studied range led to a significant improvement of the anti-wear and anti-scuffing characteristics of the PU grease, respectively. The greases properties’ dependence from the nanostructured functional additives’ introduction method and their concentration were investigated. Nanoparticles were added into the test lubricants before and after the thermo-mechanical dispersion stage. The addition of silicon dioxide and calcium carbonate NFA after the heat treatment stage led to worsening of the characteristics of the plastic material, and the increase of their concentration from 1 to 3 wt.% formed a harder structure of Li-grease. On the contrary, the addition of calcium borate NFA is recommended after the thermomechanical dispersion. The choice of nanoparticles and the method of their addition to the lubricants of various types was carried out according to the results of the previous stage of the research. Along with the analysis of the physicochemical characteristics and anti-wear and anti-scuffing properties of the lubricants, the structure of the dispersion phase of nanomodified lubricants were studied.

A Method for Predicting the Behavior of Plastics at Different Temperatures

2014 ◽  
Vol 1039 ◽  
pp. 107-111
Author(s):  
Yang Chen ◽  
Gui Qin Li ◽  
Bin Ruan ◽  
Xiao Yuan ◽  
Hong Bo Li
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Constitutive Model ◽  
Research And Development ◽  
Mechanical Behavior ◽  
Plastic Material ◽  
Different Temperatures ◽  
Plastic Parts

The mechanical behavior of plastic material is dramatically sensitive to temperature. An method is proposed to predict the mechanical behavior of plastics for cars, ranging from low-temperature low temperature ≤-40°C to high temperature ≥80°C. It dominates the behavior of plastic material based on improved constitutive model in which the parameters adjusted by a series of tests under different temperatures. The method is validated with test and establishes the basis for research and development of plastic parts for automobile as well.

scholarly journals The Effect of pH and Viscosity on Magnetophoretic Separation of Iron Oxide Nanoparticles

2021 ◽  
Vol 7 (6) ◽  
pp. 80
Author(s):  
Leonie Wittmann ◽  
Chiara Turrina ◽  
Sebastian P. Schwaminger
Keyword(s):  
Iron Oxide ◽  
Iron Oxide Nanoparticles ◽  
Colloidal Stability ◽  
Downstream Processing ◽  
Physicochemical Characteristics ◽  
Particle Migration ◽  
Aggregation Behavior ◽  
Oxide Nanoparticles ◽  
Separation Processes ◽  
Effect Of Ph

Magnetic nanoparticles (MNPs) are used for magnetophoresis-based separation processes in various biomedical and engineering applications. Essential requirements are the colloidal stability of the MNPs and the ability to be separated even in low magnetic field gradients. Bare iron oxide nanoparticles (BIONs) with a diameter of 9.2 nm are synthesized via coprecipitation, exhibiting a high saturation magnetization of 70.84 Am2 kg−1 and no remanence. In our study, zeta potential, dynamic light scattering (DLS), and sedimentation analysis show that the aggregation behavior of BIONs is influenced by pH and viscosity. Small aggregate clusters are formed with either low or high pH values or increased viscosity. Regarding magnetophoresis-based separation, a higher viscosity leads to lower magnetophoretic velocities, similar to how small aggregates do. Additionally, cooperative magnetophoresis, the joint motion of strongly interacting particles, affects the separation of the BIONs, too. Our study emphasizes the effect of pH and viscosity on the physicochemical characteristics of MNPs, resulting in different aggregation behavior. Particularly, for high viscous working media in downstream processing and medicine, respectively, the viscosity should be taken into account, as it will affect particle migration.

Estimation of Efficiency of Functional Additives in Winter Diesel Fuels of Different Hydrocarbon-Type Content

2021 ◽  
pp. 11-16
Author(s):  
E. A. Burov ◽  
◽  
L.V. Ivanova ◽  
V. N. Koshelev ◽  
D. A. Sandzhieva ◽  
...  
Keyword(s):  
Low Temperature ◽  
Group Composition ◽  
Component Composition ◽  
Saturated Hydrocarbons ◽  
Diesel Fuels ◽  
Functional Additives ◽  
Combined Use ◽  
Polycyclic Aromatic ◽  
Functional Actions ◽  
Lubricating Properties

The paper reviews the structural and group composition of three basic winter diesel fuels and its influence on the low-temperature and lubricating properties of fuels. It is shown that a high content of saturated hydrocarbons, primarily medium-molecular n-alkanes, and arenes with a higher proportion of substitution leads to a deterioration of low-temperature properties. A decrease in the proportion of medium-molecular alkanes and even a slight increase in the content of bi - and polycyclic aromatic hydrocarbons impairs the lubricating properties of the fuel.The influence of the component composition of diesel fuels on the effectiveness of anti-wear and depressor-dispersing additives was noted. The study of compatibility of additives of different functional actions revealed that the anti-wear additive based on fatty acids of tallow oil does not affect the activity of the depressant-dispersing additive, while the combined use of these additives slightly worsens the lubricating properties, but does not lead this indicator beyond the established standards.

scholarly journals Low-Temperature Rheological Properties and Microscopic Characterization of Asphalt Rubbers Containing Heterogeneous Crumb Rubbers

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4120 ◽  
Author(s):  
Mingfeng Chang ◽  
Yixing Zhang ◽  
Jianzhong Pei ◽  
Jiupeng Zhang ◽  
Min Wang ◽  
...  
Keyword(s):  
Low Temperature ◽  
Rheological Properties ◽  
Fine Particles ◽  
Physicochemical Characteristics ◽  
Crumb Rubber ◽  
Rubber Content ◽  
Evaluation Indexes ◽  
Asphalt Rubber ◽  
Linear Viscoelastic Material ◽  
Microscopic Morphology

Asphalt rubbers mixed with untreated and plasticized crumb rubbers and a compounding coupling agent were investigated in this study. The low-temperature rheological properties of asphalt rubbers at different aging levels were tested using a dynamic shear rheometer (DSR). An interconversion between linear viscoelastic material functions was used to obtain converted evaluation indexes for the asphalt rubbers at low temperatures. Lastly, the physicochemical characteristics and the microscopic morphology of the asphalt rubbers were evaluated using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM), respectively. In conclusion, the storage moduli of the asphalt rubbers containing heterogeneous crumb rubbers increased with the plasticized crumb rubber content and the aging level. The converted relaxation moduli were consistent with the change trend of the storage moduli, and the relaxation rate decreased as the plasticized crumb rubber content and the aging level increased. The process of mixing the base asphalt with crumb and plasticized crumb rubbers was physical blending, and the effect of aging on the absorption peak change of asphalt rubber with plasticized crumb rubbers was less than that of asphalt rubber with ordinary crumb rubbers. Aging deteriorated the blending between the crumb rubber and the base asphalt, and a distinct interface appeared between the crumb rubber and the base asphalt. The particle cores of the plasticized crumb rubber in the asphalt rubber were difficult to maintain. Furthermore, as the plasticized crumb rubber content increased, more fine particles stripped off the plasticized crumb rubber after aging.

scholarly journals Structure and Physicochemical Properties of Water Treated under Methane with Low-Temperature Glow Plasma of Low Frequency

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1638 ◽  
Author(s):  
Aleksandra Ciesielska ◽  
Wojciech Ciesielski ◽  
Karen Khachatryan ◽  
Henryk Koloczek ◽  
Damian Kulawik ◽  
...  
Keyword(s):  
Low Temperature ◽  
Physicochemical Properties ◽  
Treatment Time ◽  
Low Frequency ◽  
Aqueous Solubility ◽  
Physicochemical Characteristics ◽  
Scanning Calorimetry ◽  
Spin Resonance ◽  
Reflectance Ftir ◽  
Glow Plasma

Our former studies delivered a strong evidence that water indirectly treated with low-temperature, low-pressure glow plasma of low frequency (GP) changed its structure depending on the atmosphere in which such treatment was performed (air, ammonia, and nitrogen) and on the time of the treatment (0 to 120 min). In every case, water of different physicochemical characteristics and interesting biological functions was produced. Therefore, the relevant studies were extended to treating deionized water with GP under methane. The resulting samples were characterized by means of ultraviolet/visible (UV/VIS), Fourier transformation infrared-attenuated total reflectance (FTIR-ATR), electron spin resonance (ESR) and Raman spectroscopies, differential scanning calorimetry (DSC), thermogravimetry, pH, conductivity, and refractive index. The generated samples of water had entirely different physicochemical properties from those recorded for water treated with GP in the air and under both ammonia and nitrogen. The treatment of water with GP under methane did not produce clathrates hosting methane molecules. Thermogravimetry delivered an evidence that the treatment with GP increased the aqueous solubility of methane. That solubility non-linearly changed against the treatment time.

Development of Low Temperature Silicon Nitride and Silicon Dioxide Films by Inductively-Coupled Plasma Chemical Vapor Deposition

1999 ◽  
Vol 573 ◽  
Author(s):  
J. W. Lee ◽  
K. D. Mackenzie ◽  
D. Johnson ◽  
S. J. Pearton ◽  
F. Ren ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Silicon Nitride ◽  
Low Temperature ◽  
Silicon Dioxide ◽  
Vapor Deposition ◽  
Inductively Coupled Plasma ◽  
Chemical Vapor ◽  
Plasma Chemical Vapor Deposition ◽  
Inductively Coupled ◽  
Silicon Dioxide Films

ABSTRACTHigh-density plasma technology is becoming increasingly attractive for the deposition of dielectric films such as silicon nitride and silicon dioxide. In particular, inductively-coupled plasma chemical vapor deposition (ICPCVD) offers a great advantage for low temperature processing over plasma-enhanced chemical vapor deposition (PECVD) for a range of devices including compound semiconductors. In this paper, the development of low temperature (< 200°C) silicon nitride and silicon dioxide films utilizing ICP technology will be discussed. The material properties of these films have been investigated as a function of ICP source power, rf chuck power, chamber pressure, gas chemistry, and temperature. The ICPCVD films will be compared to PECVD films in terms of wet etch rate, stress, and other film characteristics. Two different gas chemistries, SiH4/N2/Ar and SiH4/NH3/He, were explored for the deposition of ICPCVD silicon nitride. The ICPCVD silicon dioxide films were prepared from SiH4/O2/Ar. The wet etch rates of both silicon nitride and silicon dioxide films are significantly lower than films prepared by conventional PECVD. This implies that ICPCVD films prepared at these low temperatures are of higher quality. The advanced ICPCVD technology can also be used for efficient void-free filling of high aspect ratio (3:1) sub-micron trenches.

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