摘要:
A hydraulic fluid that remains solids-free at temperatures as low as about -30.degree. C. and has a pour point as low as about -42.degree. C. comprises a cyclic phosphazene oligomer mixture, the structural formula of each molecule of which contains 3 or 4 units selected at random from the group consisting of ##STR1## wherein R is a fluoroalkoxy group --OCH.sub.2 (CF.sub.2).sub.m CF.sub.2 Z, where Z is hydrogen or fluorine, and m is 0 or an integer from 1 to 10; R' and R" are different alkoxyalkyloxy groups in which linear or branched C.sub.1-12 alkoxy is substituted with linear or branched C.sub.1-12 alkoxy; with the proviso that all of R, R' and R" are present in the oligomer mixture.
摘要:
Substantially linear organophosphazene polymers containing randomly distributed repeating units represented by the formulas: ##STR1## wherein R.sub.1 is a fluoroalkoxy group having the structure:F.sub.3 C--(CF.sub.2).sub.n --CH.sub.2 O--wherein n is 0 or an integer from 1 to 20 and X is fluorine and wherein at least 3 of the R.sub.1 units are different from each other and R.sub.2 represents a group with some unsaturation which enhances the curability of said polymers and represented by the formula: ##STR2## wherein R.sub.3 is an unsaturated monovalent group and R.sub.4 is selected from the group consisting of hydrogen, alkyl and alkoxy, the total number of said units ranging from 3 to about 100,000 and the R.sub.2 groups being present in an amount sufficient to enable cure of said polymers and in the range of about 0.01-50 mole percent of the total number of R.sub.1 and R.sub.2 groups are claimed. The polymers possess excellent solvent and chemical resistance as well as low volume swell properties especially when contacted with petroleum based fuels such as gasoline and particularly when contacted with oxygenated fuels such as gasohol. This makes these materials highly useful as seals such as gaskets and o-rings, hoses, coatings and the like.
摘要:
A polyphosphazene hydraulic fluid that remains solids-free on storage at temperatures down to -30.degree. C. over an extended period can be made by reacting a solution of sodium phenoxide, sodium m-methylphenoxide, sodium p-methylphenoxide and sodium trifluoroethoxide with a small stoichiometric excess of cyclic phosphonitrilic chloride oligomer, mainly trimer, and then reacting the remaining replaceable chlorine atoms with a solution of sodium trifluoroethoxide.
摘要:
Concurrently fed into a reaction zone held at about 10° C. or less are brominating agent, aluminum halide catalyst, and a solution of anionic styrenic polymer having a GPC Mn about 2000-30,000. The components are in at least two separate feed streams. The feeds are proportioned to maintain (a) the amount of aluminum halide being fed at about 0.8 mole percent or less based on the amount of aromatic monomeric units in the polymer being fed, and (b) amounts of brominating agent and unbrominated polymer in the reaction zone that produce a final washed and dried polymer product containing about 60-71 wt % bromine. The catalyst is deactivated, bromide ions and catalyst residues are washed away from the reaction mixture, and the brominated anionic styrenic polymer is recovered and dried. The dried polymer has a volatile bromobenzene content of about 600 ppm (wt/wt) or less as well as other beneficial properties.
摘要:
A polyalkylene terephthalate polymer, such as polyethylene terephthalate, polybutylene terephthalate, blends or copolymers thereof, and analogous polyester-type engineering thermoplastics, with which has been blended a flame retardant amount of brominated styrenic polymer, such as brominated polystyrene, that, prior to blending, is characterized by (a) containing less than 700 ppm Cl and having a TGA temperature for 1% weight loss of 340° C. or higher; and/or (b) having an actual Mw which is within about 20%, and preferably within about 10%, of its calculated theoretical Mw, the theoretical Mw being based upon the actual bromine content of the brominated styrenic polymer and the Mw of the styrenic polymer reactant used to produce the brominated styrenic polymer; and/or (c) being essentially free of each of the following impurities: (1) ethylene dichloride, (2) bromodichloroethane, (3) dibromochloroethane, (4) dibromodichloroethane, and (5) tribrormochloroethane. These compositions most preferably also further comprise a reinforcing amount of glass fiber and/or a flame retardant synergist dispersed therein. It is now possible to provide polyalkylene terephthalate compositions that have a UL-94 rating of V-O using both {fraction (1/16)}-inch test specimens and {fraction (1/32)}-inch test specimens, and that have superior electrical resistance characteristics as reflected by a higher comparative tracking index and greater melt stability as determined by capillary rheometry.
摘要:
This invention relates to the bromination of styrenic polymers by contacting same with a brominating agent in the presence of a bromination catalyst and, as a reaction solvent, bromochloro-methane.
摘要:
This invention relates to a thermally stable brominated polystyrene composition which contains alkali metal base (e.g., NaOH) in an amount less than about 1 wt % such that if the flame retardant is dissolved in bromochloromethane and the resultant solution is extracted with water, the resultant water extract exhibits a pH of at least about 9.0. A preferred composition of this type even when heated to 315.degree. C. for one hour did not undergo darkening--the color remained tan. Comparative samples not containing the base turned black under these same conditions. Especially useful compositions additionally have less than 500 ppm, and better still, less than 100 ppm total Cl, and at least about 67 wt % bromine. Processes for producing the compositions are also described.
摘要:
This invention relates to the bromination of styrenic polymers by contacting same with a brominating agent in the presence of a bromination catalyst and, as a reaction solvent, bromochloromethane.
摘要:
This invention relates to the bromination of styrenic polymers by contacting same with a brominating agent in the presence of a bromination catalyst and, as a reaction solvent, bromochloromethane.
摘要:
A ruthenium-phosphite complex having the formula ##STR1## wherein a is from 1 to 3; b is 1 or 2; c is from 0 to 3; and R is hydrogen, alkyl, aryl, halo, amino, acetylamino, or sulfo; and X is ##STR2## where R.sub.1, R.sub.2, and R.sub.3 are the same or different and are hydrogen or C.sub.1 to C.sub.6 linear or branched alkyl.This complex can be used to effect the reduction of unsaturated organic compounds or, when comprised of ligands having optical activity, can be used as the catalyst for effecting the asymmetric reduction of unsaturated organic compounds.