Viscosity index improver

The major use of vinylpyrrohdinone is as a monomer in manufacture of poly(vinylpyrrohdinone) (PVP) homopolymer and in various copolymers, where it frequendy imparts hydrophilic properties. When PVP was first produced, its principal use was as a blood plasma substitute and extender, a use no longer sanctioned. These polymers are used in pharmaceutical and cosmetic appHcations, soft contact lenses, and viscosity index improvers. The monomer serves as a component in radiation-cured polymer compositions, serving as a reactive diluent that reduces viscosity and increases cross-linking rates (see... 

Lubricants, Fuels, and Petroleum. The adipate and azelate diesters of through alcohols, as weU as those of tridecyl alcohol, are used as synthetic lubricants, hydrauHc fluids, and brake fluids. Phosphate esters are utilized as industrial and aviation functional fluids and to a smaH extent as additives in other lubricants. A number of alcohols, particularly the Cg materials, are employed to produce zinc dialkyldithiophosphates as lubricant antiwear additives. A smaH amount is used to make viscosity index improvers for lubricating oils. 2-Ethylhexyl nitrate [24247-96-7] serves as a cetane improver for diesel fuels and hexanol is used as an additive to fuel oil or other fuels (57). Various enhanced oil recovery processes utilize formulations containing hexanol or heptanol to displace oil from underground reservoirs (58) the alcohols and derivatives are also used as defoamers in oil production. 

Practically all lubricating oils contain at least one additive some oils contain several. The amount of additive that is used varies from < 0.01 to 30% or more. Additives can have detrimental side effects, especially if the dosage is excessive or if interactions with other additives occur. Some additives are multifimctional, eg, certain VI improvers also function as pour-point depressants or dispersants. The additives most commonly used in hydrautic fluids include pour-point depressants, viscosity index improvers, defoamers, oxidation inhibitors, mst and corrosion inhibitors, and antiwear compounds. 

Viscosity Index Improvers. VI improvers are long-chain, high molecular weight polymers that increase the relative viscosity of an oil at high temperatures more than at low temperatures. In cold oil the molecules of the polymer adopt a compressed coiled form so that the affect on viscosity is minimized. In hot oil the molecules swell, and interaction with the oil produces a proportionally greater thickening effect. Although the viscosity of the oil—polymer mixture decreases as the temperature increases, viscosity does not decrease as much as the oil alone would decrease. 

Lubricants. Petroleum lubricants continue to be the mainstay for automotive, industrial, and process lubricants. Synthetic oils are used extensively in industry and for jet engines they, of course, are made from hydrocarbons. Since the viscosity index (a measure of the viscosity behavior of a lubricant with change in temperature) of lube oil fractions from different cmdes may vary from +140 to as low as —300, additional refining steps are needed. To improve the viscosity index (VI), lube oil fractions are subjected to solvent extraction, solvent dewaxing, solvent deasphalting, and hydrogenation. Furthermore, automotive lube oils typically contain about 12—14% additives. These additives maybe oxidation inhibitors to prevent formation of gum and varnish, corrosion inhibitors, or detergent dispersants, and viscosity index improvers. The United States consumption of lubricants is shown in Table 7. 

R, mst inhibitor O, oxidation inhibitor D, detergent—dispersant VI, viscosity-index improver P, pour-point depressant W, antiwear EP, extreme pressure F, antifoam and M, friction modifier. 

Viscosity (Viscosity-Index) Improvers. Oils of high viscosity index (VI) can be attained by adding a few percent of ahnear polymer similar to those used for pour-point depressants. The most common are polyisobutylenes, polymethacrylates, and polyalkylstyrenes they are used in the molecular weight range of about 10,000 to 100,000 (18). A convenient measure for the viscosity-increasing efficiency of various polymers is the intrinsic viscosity Tj, as given by the function... 

Additives for lubricating oils providing a combination of viscosity index improvement (VII) and dispersancy have also been reported. These additives are prepared from ethyleneamines by reaction with various Vll-type polymers that have been chlorinated or modified in some other way to provide an ethyleneamine reaction site. Antimst additives for lubricating oils have been prepared by reaction of polyamines with fatty acids followed by reaction with polyalkylenesuccinic anhydrides (178,179). 

Ethyl Vinyl Ether. The addition of ethanol to acetylene gives ethyl vinyl ether [104-92-2] (351—355). The vapor-phase reaction is generally mn at 1.38—2.07 MPa (13.6—20.4 atm) and temperatures of 160—180°C with alkaline catalysts such as potassium hydroxide and potassium ethoxide. High molecular weight polymers of ethyl vinyl ether are used for pressure-sensitive adhesives, viscosity-index improvers, coatings and films lower molecular weight polymers are plasticizers and resin modifiers. 

Functionalized copolymers from dienes and p-alkylstyrenes can serve as dispersants and viscosity index improvers. The functionalities are introduced via the aromatic units [233,234]. The polymers are selectively hydrogenated to produce polymers that have highly controlled amounts of unsaturation, permitting a highly selective functionalization. The dispersant substances may also include a carrier fluid to provide concentrates of the dispersant. 

E. B. Brandes and F. C. Loveless. Dispersants and dispersant viscosity index improvers from selectively hydrogenated polymers. Patent WO... 

There have been some examples of the use of LDMS applied to the analysis of compounds separated via TLC, although not specifically dealing with polymer additives [852]. Dewey and Finney [838] have described direct TLC-spectroscopy and TLC-LMMS as applied to the analysis of lubricating oil additives (phenolic and amine antioxidants, detergents, dispersants, viscosity index improvers, corrosion inhibitors and metal deactivators). Also a series of general organics and ionic surfactants were analysed by means of direct normal-phase HPTLC-LMMS [837]. Novak and Hercules [858] have... 

Similarly, the polymerization process will pull the isobutylene selectively out of the C4 stream. Polyisobutylene is used mainly as a viscosity index improver in lubricating oils and in caulking and sealing compounds. Some of the low molecular weight polyisobutylenes are particularly suited for use in the construction field because it doesn t solidify. They remain a tacky fluid and when properly formulated with clay fillers, etc., take on the properties of a sticky, putty-like substance. 

The polymerization process is a low temperature catalytic reaction. The type of polymer produced is strongly affected by the reaction temperature. Low temperatures give low molecular weight polymers, the kind useful in caulking compounds and as a viscosity index improver for motor oils. 

Uses. About 60% of the MA produced is used to make unsaturated polyester and aikyd resins, which are formed by reaction of MA with glycols. Polyester resins are used in the fabrication of glass fiber reinforced parts. Applications include boat hulls, automobile body parts, patio furniture, shower stalls, and pipe. Aikyd resins are mostly used in coatings (paint, varnish, lacquers, and enamels). MA also is widely used as a chemical intermediate in the manufacture of plasticizers and dibasic acids (fumaric, maleic, and succinic). About 15% of MA production goes into the manufacture of viscosity index improvers and dispersants used as additives in lube oils. Several agricultural chemicals are based on maleic anhydride, the best known being Malathion. 

The patent literature on jet fuels is very extensive. Some examples of patents granted on jet fuels are as follows Fox Britton (Ref 2) claim the incorporation of viscosity-index improvers in jet fuels to improve engine start-up combustion efficiency over a wide range of temps. Materials claimed to be effective are ethyl glycol, Acryloid Sanotex... 

Branched substituents on the nucleus of PS impede the rotation but do not decrease the Tt to any great extent. The solubility parameter decreases as the size of the substituent alkyl groups increases. Thus although PS is not soluble in aliphatic hydrocarbon liquids, poly / cydohexylstyrene is soluble and serves as a viscosity index improver for lubricating oils. 

The viscosity index improver was prepared after reacting with W-phenyl-p-phenylenediamine. 

Vinci et al. (3) prepared automotive oil viscosity index improvers that consisted of copolymers of C12-C15 methacrylates with 2-ethylhexyl methacrylate and poly(ethylene-c >-propylene) with 2-ethylhexyl methacrylate, then blended in... 

Poly(ethylene-co-4-mcthyl-1 -pentene) was prepared by Colin et al. (2) and used as fibers, thermoplastics, and as oil viscosity index improvers. 

Figure 14 illustrates a comparison between solvent extraction yields predicted from adsorption analyses and actual raffinate yields in commercial solvent extraction plants. Few commercial yields have ever equaled those obtained by adsorption analyses and none has exceeded those values hence, curve A (45° angle) represents the ultimate in solvent extraction. Curve B represents solvent extraction in commercial equipment on stocks ranging in viscosity index from +25 to +110, and for viscosity index improvements ranging from 30 to 130. Extremely viscous stocks or those which require a very large viscosity index improvement have been observed to follow more closely lines C and D. 

The improvements have come by way of petroleum oils with viscosity index improvers, or synthetics with naturally high viscosity index. The problem of packing deterioration, or rusting, is chiefly a chemical matter. Hydraulic fluids for the various applications include those made from petroleum, synthetic oils, and aqueous solutions containing antifreeze and rust inhibitors. Antifoam agents are necessary in some hydraulic fluids. 

Viscosity index improves make lube oil more effective over a wide range of temperatures. 

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