Rubbers phosphorus-containing

Among phosphorus-containing additive flame-retardants, phosphates are mostly applied as secondary plasticizers in formulations of flame-retarded plasticized PVC. Other additive agents are admixed with natural and synthetic rubbers, polyester and epoxy resins, polyurethane foams, polystyrenes and polyethylenes, etc. 

NR is c/ s -1,4-polyisoprcnc, of molecular weight 200,000-500,000, but it also contains a small level of highly important non-rubber constituents. Of these, the most important are the proteins, sugars and fatty acids which are antioxidants and activators of cure. Trace elements present include potassium, manganese, phosphorus, copper and iron which can act as catalysts for oxidation. 

In a 2-1., three-necked, round-bottomed flask (Note 1) fitted with a sealed stirrer having a Teflon blade and, on the two side necks, with gas-outlet tubes connected by rubber or plastic tubing to an etficient hydrogen chloride absorption trap (Note 2), 464 g. (2 moles) of D,L-10-camphorsulfonic acid (Note 3) is mixed with 416 g. (2 moles) of phosphorus pentachloride (Note 4). The flask is immersed in ice water and, as soon as the mixture has liquefied sufficiently, the stirrer is started but must be run slowly at first because of lumps. When the vigorous reaction has subsided, the cooling bath is removed and stirring continued until the chloride is completely dissolved (Note 5). The mixture is then allowed to stand for 3 or 4 hours. It is poured Hood ) onto 500 g. of crushed ice contained in a 2-1. beaker. This mixture is immediately poured into a second beaker containing a similar quantity of crushed ice. The mixture is then poured back and forth between the two beakers until all evidence of reaction has disappeared (Note 6). The fine white product is collected on a... 

Chemical plant safety, 68 Chemical stability/reactivity assessment, 68 Chemical vapour deposition (cvd), 69 Chlorinated paraffins, 69 N-chlorinated phosphorus amides, 69 Chlorinated poly(dimethylsiloxanes), 69 Chlorinated rubber, 69 Chlorine-containing systems, 70 Chlorite salts, 70 Chlorofluorocarbons, 71 N-Chloronitroamines, 71 Chlorophyll, 71... 

Two important sources of elemental phosphorus in soil are the creation of slag piles during the production of white phosphorus, and the disposal of solid wastes containing elemental phosphorus in hazardous waste landfills (Berkowitz et al. 1981 Idler et al. 1981). The field use of WP/F and red phosphorus/butyl rubber smoke/obscurant releases elemental phosphorus into soil primarily as unburnt phosphorus in munitions (Berkowitz et al. 1981 ... 

Wear nitrile rubber gloves, laboratory coat, eye protection, and, if necessary, a self-contained breathing apparatus. Cover the spill with a 1 1 1 mixture by weight of sodium carbonate or calcium carbonate, clay cat litter (bentonite), and sand. When the phosphorus tribromide has been absorbed, scoop the mixture into a plastic pail and, in the fume hood, very slowly add the mixture to a pail of cold water. Allow to stand 24 hours. Test the pH of the solution and neutralize if necessary with sodium carbonate. Decant the solution to the drain. Treat the solid residue as normal refuse.8... 

One hundred four milliliters of phosphorus(V) sulfochlo-ride (1.0 mol) is placed in a 500-ml. three-necked flask. The flask is fitted with a mercury-sealed stirrer, a water-cooled condenser to which a drying tube containing barium oxide is attached in a horizontal position, and a 250-ml. dropping funnel containing 58 ml. of anhydrous ethanol (1.0 mol). All joints may be rubber stoppers or, preferably, nonlubricated standard-taper ground-glass joints. 

Elemental sulfur is mainly used (ca. 85 to 90%) in the manufacture of sulfuric acid. It is also utilized in the production of sulfur dioxide, carbon disulfide, phosphorus(V) sulfide, thiosulfates and sulfur dyes, sulfur-containing putty, gunpowder and fireworks, sulfur concrete, slow release fertilizers and pharmaceuticals and as a rubber vulcanization agent. 

Elastomers. Many applications of rubbers such as tires, gaskets, and washers normally do not require flame resistance. When improvement in flammability is required, it can be achieved by the addition of halogen-containing materials, phosphorus compounds, oxides of antimony, and combinations of these materials. Rubbers containing chlorine and silicon atoms, for example. Neoprene and Silicone, have self-extinguishing properties. Rogers and Fruzzetti (10) described the flame retardance of elastomers. 

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