Thick Oils Research Articles

A superhydrophobic graphene@copper mesh irradiated by laser for efficient oil/water separation

Oil/water separation has become a global task due to the worldwide increase of oily wastewater. As such, developing membranes that could separate oil from water is of high importance. The aim of this work is to develop a copper mesh with superhydrophobic properties that has a high oil/water separation efficiency. To achieve this, a copper mesh was coated with a monolayer graphene/polydimethylsiloxane (PDMS) mixture in a one-step immersion process. Combining a fixed percentage of graphene (3 %) with three different ratios of PDMS (10 %, 5 % and 2.5 %) allowed us to investigate the effect of PDMS on the contact angle of the fabricated meshes. The Cu-mesh prepared by a 2.5 % PDMS solution displayed the highest contact angle of 133.3o ± 0.5. Irradiating the samples with a Nd:YAG −1064 nm laser, that scans the whole area of the mesh, resulted in the improvement of the hydrophobic properties of the surface. It was also found that the laser-to-sample distance influenced the improvement of the contact angle. Graphene@Cu mesh, treated by laser at a distance of 1.5 mm above the laser focal point showed superhydrophobic characteristics with a contact angle of 155.6o ± 0.3. The oil/water separation efficiency was measured for the fabricated meshes. The best developed mesh showed potential in separating both thick oils, such as HD-40 engine oil, and thin oils, such as toluene, from water with separation efficiencies of 92 % and 95 %, respectively.

PRODUCTION OF ESTERS BY ETERIFICATION OF FATTY ACIDS OF SUNFLOWER, OLIVE AND SOYBEAN OILS WITH MANNITOL, SORBITOL AND XYLITOL

Polyol esters are widely used in various fields of science and technology, food industry, sanitation, medicine, cosmetics, etc. In engineering, polyol esters are mainly used as high-temperature lubricating oils․Esters of polyols with a degree of substitution from 1:1 to 3:1 are used as emulsifiers, stabilizers, defoamers, dispersants and detergents. Esters of saturated carboxylic acids С12 – С18 – with a degree of substitution from 4:1 to 6:1 are thick or hard oils and are used in medicine, pharmacy and cosmetology. In our early studies, with the esterification of mannitol and other C4 – C6 polyols with some higher aliphatic acids in molar ratios of 1: 3÷6, various esters were obtained. The synthesized oil-like products were similar in their physicochemical and rheological properties to natural fats and oils and had melting points in the range of –10...64 °C. However, differing from artificial oils, natural fats and oils contains variety of saturated and unsaturated fatty acids C6 – C12. Therefore, in order to obtain more natural oil and fat substitutes, it seems appropriate to obtain esters of higher polyols with a complex of natural fatty acids. This paper presents data on obtaining a complex of fatty acids of sunflower, olive and soybean oils and further synthesis of esters with mannitol, sorbitol and xylitol in molar ratios of 1: 3...6. The studies were carried out according to the following scheme: A) hydrolysis of sunflower, olive and soybean oils with an alkali solution, with the formation of a mixture of carboxylic acids, consisting mainly of oleic, linoleic, stearic and palmitic acids; B) neutralization of alkali salts, isolation and drying of fatty acids mixtures; C) esterification of mannitol, sorbitol and xylitol with fatty acid complexes; D) purification and drying of non-glyceride oils; E) determination of the main physicochemical properties of the obtained artificial oils. The reaction progress is monitored by HPLC method on an Agilent Infinity II HPLC 1260 System instrument and by IR spectra method on an IKS 29 instrument. The completion of polyol esterification reactions with fatty acid complexes is determined by the disappearance of absorption bands in the IR spectra in the region of 1740 and 2500...2700 cm˗1. Outputs of artificial oils in optimal conditions reach 95-97%. Non-glyceride oils are intended for testing as substitutes for natural oils and fats.

OBTAINING MONO-SUBSTITUTED SORBITAN ESTERS

Polyol esters have recently been widely used in various fields: medicine, cosmetics, food industry, sanitation, science and technology. This is ensured by the specific physical and chemical properties of this group of substances. Polyols are polyhydric alcohols obtained by hydrogenation of monosaccharides. These compounds are found in natural sugars and are used in food and as dietary sweeteners. Esters of polyols with carboxylic acids are functionally divided into several groups. Thus, esters of saturated carboxylic acids С12-С18 - with a degree of substitution from 4:1 to 6:1 are mainly thick and hard artificial oils and, accordingly, are used in medicine, pharmacy and cosmetology. In engineering, polyol esters are mainly used in the machine tool, automotive and aviation industries as high temperature lubricating oils. Polyol esters containing C4-C12 carboxylic acids or unsaturated carboxylic acids are generally liquid or soft oils for use in ointments, cosmetic preparations, and the like. A variety of polyol esters with a degree of substitution from 1:1 to 3:1 are particularly widely used as emulsifiers, stabilizers, defoamers, dispersants and detergents. Our previous studies have focused on obtaining oil-like esters with the maximum degree of substitution. Using the examples of mannitol, sorbitol, xylitol, and erythritol, numerous samples of esters were obtained and the optimal conditions for esterification reactions, isolation, and analysis of the obtained products were worked out. In this work, we set a goal to study the patterns of obtaining monosubstituted esters of sorbitol and sorbitan, which are of interest as nonionic emulsifiers and detergents. In particular, the technical regulations of the Eurasian Economic Community allow the use of emulsifiers: E491 – sorbitan monostearate, E492 – sorbitan tristearate, E493 – sorbitan monolaurate, E494 sorbitan monooleate, E495 sorbitan monopalmite. Sorbitan monopalmitate or span 40 emulsifier is a flaky yellowish brown wax. It consists of a mixture of mono- and dianhydrides of sorbitan. Its liquid crystal structure is similar to the natural structure of the skin, easily absorbs water and effectively moisturizes the skin, transfers nutrients and medicinal substances deep into the skin.

Lubricant Replenishment in Rolling Bearing Contacts

It is generally assumed that starved lubricated contacts in rolling element bearings are replenished by side flow. The rolling elements partly push the lubricant to the side of the contacts after which the re-flow will provide fresh lubricant for the next rolling element. This re-flow is driven by surface tension and restricted by the viscosity. Hence, thick oils or greases may yield problems here, which is generally observed in practice. This paper quantifies this re-flow by means of a numerical model using a so-called thin layer/film assumptions. The results here show that this form of replenishment may happen to some extent in single contacts but for sure not in rolling element bearings. There are two reasons for this: the time between successive overrollings is too short and secondly, the centrifugal effects on the inner ring will drive the flow in a vertical direction rather than transversely. This applies to cylindrical roller bearings (CRB)-type of surfaces. This may be different for tapered or spherical bearings, which should be the topic of future research.

Synthesis of 1-O-(2?,3?-dihydroxypropyl)5-deoxy-?-D-ribofuranosides with (CH3)2As, (CH3)2As?S or (CH3)3As+ groups as substituents at the 5-position

Eight arsenic-containing ribosides were prepared from dimethyl(1-O-methyl1-5-deoxy-2,3-O-isopropylidene-β-D-ribofuranos-5-yl)arsine and (2′S)-dimethyl[1-O-(2′,3′-isopropylidenedioxypropyl)-5-deoxy-2,3-O-isopropylidene-β-D-ribofuranos-5-yl]arsine. Reactions of the arsines with sulfur produced the compounds with a (CH3)2As &&dbond S group as substituent in the 5-position. Treatment of these dimethyl(ribosyl)arsine sulfides with trifluoroacetic acid water removed the isopropylidene groups and gave the unprotected derivatives as thick oils in 80% yield. The arsines and methyl iodide gave the protected trimethyl(ribosyl)arsonium iodides. These arsonium iodides were reacted with trifluoroacetic acid/water. Anomeric mixtures of the deprotected compounds were isolated. Deprotection of the dimethyl(ribosyl)arsines proceeded without anomerization. Reaction of the dimethyl[1-O-(2′,3′-dihydroxypropyl)-5-deoxy-β-D-ribofuranos-5-yl]arsine with methyl iodide produced the pure β-anomer of the arsonium iodide. The yields in these reactions were approximately 80%.

Effects of Oil Viscosity on Seizure

Oil viscosity is an important factor in oil film formation ; its effects on the scoring resistance of gears have been examined. In spite of scoring taking place easily where specific sliding is high, few papers have treated the specific sliding as important. As a basic study to establish gear design procedures for better resistance to scoring, we examined the effects of oil viscosity on antiseizure capacities of mineral base oils. The experiments were carried out using a two-cylinder test rig under various specific sliding conditions. In the higher specific sliding range the antiseizure capacities rise with an increase in oil viscosity. In the lower range, however, the effects are nominal ; thin oils are applicable in severe conditions of heavy load, high sliding velocity, and high bulk temperature where thick EP oils are ordinarily used. A method for applying these results to the scoring design of case-hardened spur gears was proposed.

Effects of Oil Viscosity on Seizure.

Though the effects of oil viscosity, which is an important factor for oil film formation, on the scoring resistance of gears have been examined, in the former studies the significant influences of specific sliding on the antiseizure capacities of lubricating oils were not taken into account. Thus, in this paper, as a basic study to establish the design for the scoring of gears, the effects of oil viscosity on antiseizure capacities of mineral base oils are examined by two-cylinder tests under various specific slidings. Though in the higher specific sliding range the antiseizure capacity rises with an increase in oil viscosity, in the lower range the effects are minute and thin oils are also applicable to the severe conditions of heavy load, higher sliding velocity, and higher bulk temperature where thick EP oils are ordinarily used. A method is proposed for applying these results to the scoring design of case-hardened spur gears.

An Oscillating Blade Microtome for Rubber

Abstract In a study of the equilibrium swelling of rubber in thick oils, thin samples, about 0.1 mm thick, were required so that equilibrium could be reached within a reasonable time. Thin sheets can be molded, but they are frequently very anisotropic and therefore undesirable. Although it is possible to microtome very thin samples of rubber at sufficiently low temperatures where it is relatively stiff, only small areas are obtainable, and it is a difficult and inconvenient process if several square centimeters are required. An oscillating blade microtome of simple design was therefore constructed, capable of cutting sufficiently thin slices, about 2 cm square, at room temperature. Because of the sawing action of the blade the cutting force is greatly reduced and deformation of the sample is minimized.

An oscillating blade microtome for rubber

Abstract In a study of the equilibrium swelling of rubber in thick oils, thin samples, about 0.1 mm thick, were required so that equilibrium could be reached within a reasonable time. Thin sheets can be molded, but they are frequently very anisotropic and therefore undesirable. Although it is possible to microtome very thin samples of rubber at sufficiently low temperatures where it is relatively stiff, only small areas are obtainable, and it is a difficult and inconvenient process if several square centimeters are required. An oscillating blade microtome of simple design was therefore constructed, capable of cutting sufficiently thin slices, about 2 cm square, at room temperature. Because of the sawing action of the blade the cutting force is greatly reduced and deformation of the sample is minimized.

Reaction of acetylene with siloxanes and silanes containing silicon-attached hydrogen

1. The reaction of acetylene with disiloxanes (tetramethyl-, tetraethyl-, and diethyldimethyl-disiloxanes) was investigated. Polymers were obtained in the form of thick oils. 2. A study was made of the reaction of acetylene with chlorosilanes containing silicon-attached hydrogen (chloromethylphenyl- and dichloromethyl-silanes), and it was shown that at atmospheric pressure in presence of H2PtCl6 reaction proceeds with formation of 1,2-bis(alkyl(or aryl)chlorosilyl)ethanes.

Some special features of organic polymers containing phosphorus

AbstractResults obtained in the investigation of polymers containing pentavalent phosphorus in the main polymer chain are presented. A number of polyamides and polyesters derived from phosphorus‐containing dicarboxylic acids have been synthesized. Two types of dicarboxylic acids were used: alkyl‐ or aryl‐phosphinic acids (I) and bis‐carboxyphenyl‐phosphine oxides (II): magnified image their chloroanhydrides or esters being used in the reaction. To obtain polyesters, various glycols or dihydric phenols were used as the second component. For preparing polyamides, aliphatic diamines were used as the second component. The nature of the starting materials has a very marked effect on the properties of the polymers obtained. Polyesters with an aliphatic chain are viscous, thick oils or low‐melting resins. Polyesters with aromatic unit are high‐melting, solid elastic substances. Comparison of the properties of the polymers synthesized by us with the properties of polymers of related composition not containing phosphorus, shows that the introduction of phosphorus into the chain leads to molecules of much greater flexibility. For this reason the softening points of the phosphorus‐containing polymers are much lower than those of their carbon analogues.