INDEX rubber, synthetic

Saturable dye absorber, 14 677 Saturated aqueous salt solution, 9 34 Saturated calomel electrode (SCE), 9 571 Saturated fatty acids, 10 829, 830 Saturated hydrocarbons adsorbent affinity, 1 674 adsorption by zeolites, 1 624 fluorine reactivity with, 11 831 isomerization of, 12 172—173 Saturated polyester resins, based on trimethylpentanediol, 12 673 Saturated polyesters, 10 7 Saturated synthetic rubber, 10 705 Saturation and coating processes, 10 12-13 Saturation bonding, 17 509-510 Saturation color, 19 262 Saturation concentration, 15 677 Saturation index... 

SBR is the most widely used synthetic elastomer. It is an amorphous random copolymer consisting of a mixture of l.2, cis and trans isomers. Cold SBR produced at —20 C consists of 17% 1,2. 6% cis and 77% trans isomers of polybutadiene. This commercial product has a Tt of -60 C, an index of refraction of 1.534S, and a coefficient of linear expansion of 66 X 10 s cm/ cm C. Because of the high percentage of the trans isomer, it is less flexible and has a higher heat buildup, when flexed, than Hevea rubber. Although carbon black-filled or amorphous silica-filled SBR has useful physical and mechanical properties, the SBR gum rubber is inferior to Hevea rubber. 

Budavari, S., ed. (1996) Merck Index, 12th Ed., Whitehouse Station. NJ. Merck, pp. 248-249 Burroughs, GE. (1977) Health Hazard Evaluation Determination. Firestone Synthetic Rubber... 

Index - [AMNES - AMINES,AROMATIC - PHENYLENEDIAMINES] (Vol 2) -for butyl rubber [ELASTOhffiRS, SYNTHETIC - BUTYL RUBBER] (Vol 8) - 1,2-dihydroqumolmes as [QUINOLINES AND ISOQUINOLINES] (Vol 20) -for isoprene rubber [ELASTOhffiRS SYNTHETIC - POLYISOPRENE] (Vol 9)... 

For synthetic rubbers, the mill homogenization is generally omitted, although it is specified as an alternative where the appropriate evaluation procedure requires it before measuring Mooney viscosity. Different conditions are given for specific polymers. The mill method of ISO 248 for determining volatile matter is specified but the oven method may be substituted if the material sticks to the mill rolls. Regardless of which volatile matter method is used, the mill procedure is required to dry samples for any chemical tests needed - unless this is not possible. To the uninitiated at least, this is not a model of clarity. Vulcanization characteristics are determined for synthetic rubbers, but not plasticity retention index. 

PETROCHEMICALS. Chemicals derived from petroleum and, more specifically, substances or materials manufactured from a component of crude oil or natural gas. See Fig. 1 In this sense, ammonia and synthetic rubber made from natural gas components are petrochemicals. Many of these chemicals are described in separate articles in this encyclopedia. Check alphabetical index. 

Synonyms Butyl dodecanoate Empirical C16H32O2 Formula CH3(CH2)ioCOO(CH2)3CH3 Properties Liq. sol. in mostorg. soivs. insol. in water m.w. 256.43 dens. 0.860 (20/4 C) m.p. -7 C b.p. 194 C (30 mm) ref. index 1.435 (20 C) Precaution Combustible Uses Textile lubricant plasticizer in food-contact rubber articles for repeated use synthetic flavoring agent in foods and pharmaceuticals... 

Synthetic Polyisoprene Rubbers. M. J. Shuttleworth and A. A. Watson Index... 

ML value is an index of the mechanical property of synthetic rubber. It is related to the averaged molecular weight of synthetic rubber products. In butadiene rubber production, the ML value should be controlled within 43 to 47. Too high ML values correspond to insufficiency of elasticity, while too low ML values correspond to low tensile strength of products. Table 14.4 illustrates some data of production records about the factors affecting ML values in production. It has been found that there are five chief factors influencing the ML values in production X (feed rate of butadiene monomer), X2 (feed rate of solvent oil), Xj (feed rate of catalyst), X4 (temperature of feed), X5 (temperature of the lower part of the first reactor). 

ACS (2001) United States Synthetic Rubber Program, 1939-1945. http //www.rockbridgegroup.com/ review/new nhcl/nhcl 2/landmarks/rbb/index.html Adamy, M., van Herk, A.M., Destarac, M. and Monteiro, M.J. (2003) Macromolecules, 36,2293. Adrian, J., Esser, E., HeUmann, G. and Pasch, H. (2000) Polymer, 41,2439. 

The early workers in the field of lubricants observed that small amoimts of rubber dissolved in a mineral oil raised the VI substantially. However, high unsaturation in the polymer led to oxidation and sludge formation. Otto et al. [3] discovered that this could be overcome through the use of a synthetic polymer prepared from the light ends of the gasoline. Similar observations were later made for polymethacrylates by Rohm and Haas Co. [4,5] and for polyisobutylenes by Farbenindustrie AG [6,7]. Because these materials were initially used mainly to increase the VI, they became known as the viscosity index improvers. 

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