Magnesium oxide modulus

The ash content of furnace blacks is normally a few tenths of a percent but in some products may be as high as one percent. The chief sources of ash are the water used to quench the hot black from the reactors during manufacture and for wet pelletizing the black. The hardness of the water, and the amount used determines the ash content of the products. The ash consists principally of the salts and oxides of calcium, magnesium, and sodium and accounts for the basic pH (8—10) commonly found in furnace blacks. In some products potassium, in small amounts, is present in the ash content. Potassium salts are used in most carbon black manufacture to control stmcture and mbber vulcanizate modulus (22). The basic mineral salts and oxides have a slight accelerating effect on the vulcanization reaction in mbber. [Pg.543]

Reasons for use abrasion resistance, cost reduction, electric conductivity (metal fibers, carbon fibers, carbon black), EMI shielding (metal and carbon fibers), electric resistivity (mica), flame retarding properties (aluminum hydroxide, antimony trioxide, magnesium hydroxide), impact resistance improvement (small particle size calcium carbonate), improvement of radiation stability (zeolite), increase of density, increase of flexural modulus, impact strength, and stiffness (talc), nucleating agent for bubble formation, permeability (mica), smoke suppression (magnesium hydroxide), thermal stabilization (calcium carbonate), wear resistance (aluminum oxide, silica carbide, wollastonite)... [Pg.50]

Conventional SMC is prepared from unsaturated polyester resin and styrene, together with magnesium or calcium oxides or hydroxides. The bases serve to thicken the styrene-polyester solution, probably through ionomer formation.Usually, SMC is used together with fillers such as calcium carbonate and glass fiber reinforcement for high modulus. [Pg.207]