Hygroscopicity of synthetic oils

Echin, A. I.; Novosartov, G. T.; Попова, Э. А.

doi:10.1007/bf00730584

Cited by 6 publications

(4 citation statements)

References 2 publications

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“…Considering increased moisture content for organic materials, the maximum reported deposition rate has been 4 µg of haze over a 37.5 cm 2 area [21]. Mineral oils generally have very low hygroscopicity, compared to glycerol [37,38]. Taking the worst case of a glycerol haze, full isotherms (from 10 to 100 °C) have been published [38].…”

Section: Renaissance Waxmentioning

confidence: 99%

FTIR surface analysis for conservation

Thickett

Pretzel

2020

Herit Sci

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Several FTIR techniques are surface-sensitive. This sensitivity can be utilized to help with a wide range conservation issues. Examples from object degradation studies, conservation materials performance assessment and monitoring are presented. These are used to discuss the issues, advantages and information that can be drawn from studies. Glass degradation was quantified on the surfaces of cover glasses from important Nineteenth century daguerreotypes using Germanium attenuated total reflectance. The very limited information depth endowed by the high refractive index crystal gave good sensitivity when other techniques such as sectioning and scanning electron microscopy had failed to detect a gel layer present. The inner glass surface was always more deteriorated and the degree of deterioration inversely correlated with the distance between the inner glass surface and the daguerreotype or brass matt surface. Reflection-absorption FTIR microscopy has been combined with an excimer laser to determine the water content of a series of sections through the depth of a wax. A common wax used to protect metals has been found to take up liquid water in humid environments and hold that water close to or at the metal surface. An adjustable height gold mirror was used to bounce the IR beam many times across a surface, which can give extreme sensitivity. Haze and smoke generators are increasingly being introduced into displays or for special events or filming. Very low detection limits (1 ng) were found using gold coated glass slides to detect haze deposits.

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Section: Renaissance Waxmentioning

confidence: 99%

FTIR surface analysis for conservation

Thickett

Pretzel

2020

Herit Sci

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“…The presence of functional additives in the MDPN-S and MDPN-S2 oils does not have a definitive effect on their behavior [3]. …”

mentioning

confidence: 88%

Hygroscopicity of poly-α-olefin based oils

Naumova¹,

Tyshchenko²,

Surovskaya³

et al. 2011

Chem Technol Fuels Oils

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HYGROSCOPICITY OF POLY-α α α α α-OLEFIN BASED OILST. I. Naumova, V. A. Tyshchenko, G. V. Surovskaya, and V. V. Grigor'ev ____________________________________________________________________________________________________ Publicly owned joint-stock company Srednevolzhskii Nauchno-Issledovatel'skii Institut po Neftepererabotke. The hygroscopicity of poly-α-olefin based oils is studied. Moisture saturation of all oils used in this study is reached by 60 h into the tests. The dependence of the hygroscopocity of the oils on the molecular mass of the oligomer is determined. The presence of functional additives in the oils does not greatly affect their hygroscopicity, while polar compounds (products of aging) sharply (almost twofold) increase the hygroscopicity.

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“…In describing the water absorption of synthetic lubricants, Echin, Novosartov and Popova (1981) stated that hygroscopicity of oils based on esters increased with increasing relative humidity of the air (according to Henry's law) and with increasing temperature.…”

Section: Hygroscopicitymentioning

confidence: 99%

Effects of Water in Synthetic Lubricant Systems and Clathrate Formation: A Literature Search and Review

Rohatgi

2001

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EXECUTIVE SUMMARYMoisture is a universal contaminant of refrigeration systems, and a scientific understanding of the effects of water in these systems is needed for their proper design, efficient operation, and reliable service. The effects of water on chlorofluorocarbons and mineral oil have been extensively studied. In these non-polar systems with low solubility for water, moisture levels are usually controlled to twenty five parts per million or less to avoid free water and the associated corrosion of metals, compatibility problems with polymeric materials, and possible ice formation in expansion valves, capillary tubes, or evaporators. The phase-out of chlorofluorocarbon/mineral oil systems and the introduction of alternative hydrofluorocarbon (HFC) refrigerants and their compatible synthetic lubricants have once more raised concerns about the effects of water on the stability of refrigeration systems. The HFC/synthetic lubricant systems are polar and have good solubility for moisture, thus present reduced risk of free water with its associated problems. The current common practice of equipment manufacturers is to allow moisture levels of 50-100 parts per million (ppm) or less in new equipment with HFC and synthetic lubricants. However, service practices are not well controlled and may lead to high levels of water in the refrigeration system. Because of the different types of synthetic lubricants and system designs encountered in the refrigeration and airconditioning industry, initial investigations into the effects of excess water with the HFC/synthetic lubricant working fluids are limited, proprietary, or of a screening nature.There has not been a reported in-depth study of the effects of moisture on the long-term stability of the HFC/synthetic lubricant systems. Such a study would assist the equipment manufacturers in defining allowable maximum limits of water concentration for ii satisfactory long-term operation of the HFC/synthetic lubricant systems, and evaluating potential difficulties associated with the presence of excessive water.Under ARTI 21-CR Project 610-50035-01, Spauschus Associates, Inc. has compiled and critically evaluated the current state of knowledge of the effects of water on the stability of HFC/synthetic lubricant systems to identify key areas requiring further investigation. An extensive literature search was conducted and a confidential survey was prepared and sent to compressor, lubricant, desiccant and filter-drier manufacturers to determine the industry specifications on the amount of water allowable in the HFC/synthetic lubricant systems. Following are highlights from the extensive literature review and analysis of the survey:• Clathrate hydrates, first discovered in 1810, are solid solutions formed when water molecules are linked through hydrogen bonding creating cavities that can enclose various guest molecules also know as hydrate formers. The formation, nucleation, growth, decomposition, structures, properties, and thermodynamic phase equilibria have been reported for a num...

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Hygroscopicity of synthetic oils

Cited by 6 publications

References 2 publications

FTIR surface analysis for conservation

FTIR surface analysis for conservation

Hygroscopicity of poly-α-olefin based oils

Effects of Water in Synthetic Lubricant Systems and Clathrate Formation: A Literature Search and Review

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