Dense fillers

Large amounts of iaert fillers, such as whiting, talc, and clays, can be added. Very dense fillers, such as barium or strontium sulfates, are used to make compounds intended for sound-deadening appHcations. In contrast, high levels of reinforcing fillers, such as carbon black, produce undesirable properties ia the final product. 

Other dense fillers are useful for sound-deadening purposes, such as barium sulfate. Likewise, tungsten and bismuth can be used in POs to increase density and create a metal-like heaviness in consumer products. This quality is said to be potentially useful for semi-durable products like cosmetics/personal-care packaging (lipstick tubes, etc.), where the density of metal suggests quality, but where it would be cost-prohibitive to produce the product in metal. Standard plastics processing can be used with these filler compounds, according to manufacturer Clariant Masterbatches [7-19]. 

From drawing it is visible, that to maintenance growth schnngite there is directly proportional increase in density of films. Increase of density of composite films is cansed by increase in their concentration of more dense filler. 

To find the HSP for a filler, take a range of solvents (typically 15-20) and attempt to disperse the filler in the solvent. Fillers that are compatible with the solvent tend to remain in dispersion, and those that are incompatible will fail to get dispersed or crash out of the dispersion very quickly. Clearly, there is some degree of empirical judgment with this approach, which is why one uses multiple solvents to reduce statistical errors. A dense filler will, for example, settle out faster in less dense solvents, so some allowance has to be... 

Dense fillers are used when heft, weight, or sound/ vibration damping is required. Heft is the perception of quality associated with products that feel substantial in the hand. Dense formulations are used in washing machine counterweights to reduce vibration. Formulations include iron slag in polypropylene or epoxy. Dense fillers include barium sulfate (density 45 g cm ), magnetite (density 5.0 g-cm ), micaceous iron oxide (density 5.0 g cm ), and metals (density 8-20 g-cm ). 

In recent years, synthetic polymeric pigments have been promoted as fillers for paper. Pigments that ate based on polystyrene [9003-53-6] latexes and on highly cross-linked urea—formaldehyde resins have been evaluated for this appHcation. These synthetic pigments are less dense than mineral fillers and could be used to produce lightweight grades of paper, but their use has been limited in the United States. 

Reverse cleaners operate on the same principles as forward cleaners (20). Contaminants less dense than water migrate toward the center of the cleaner and exit as a separate (reject) stream from the pulp slurry. Reverse cleaners are used to remove adhesive and plastic particles as well as paper filler particles and lightweight particles formed from paper coatings. 

Glassy, or vitreous, carbon is a black, shiny, dense, brittle material with a vitreous or glasslike appearance (10,11). It is produced by the controUed pyrolysis of thermosetting resins phenol—formaldehyde and polyurethanes are among the most common precursors. Unlike conventional artificial graphites, glassy carbon has no filler material. The Hquid resin itself becomes the binder. 

It is precisely the loosening of a portion of polymer to which the authors of [47] attribute the observed decrease of viscosity when small quantities of filler are added. In their opinion, the filler particles added to the polymer melt tend to form a double shell (the inner one characterized by high density and a looser outer one) around themselves. The viscosity diminishes until so much filler is added that the entire polymer gets involved in the boundary layer. On further increase of filler content, the boundary layers on the new particles will be formed on account of the already loosened regions of the polymeric matrix. Finally, the layers on all particles become dense and the viscosity rises sharply after that the particle with adsorbed polymer will exhibit the usual hydrodynamic drag. 

However, if the volume ratio between the filler and the matrix is too high, the composite can become brittle, similar to dense graphite, and the advantage of composite plates in cost reduction will not exist. Hence, the normal composite plate contains about 50-80% fillers so as to have balanced electrical conductivity and mechanical properties with the accepted low cost. 

Packing microspheres more closely by using external force results in some sections in which the spheres touch each other and other sections in which there is an intervening layer of binder polymer. The first type is markedly weaker than the second, and syntactic foam failure starts there. The practical conclusion is obviously that, in order to obtain strong syntactic foams, the microspheres should be packed somewhat less densely, so that thin binder layers are present between all filler particles 7 8). 

Magnesium carbonate (MgC03) varies from dense material used in magnesite bricks to the very low density hydrated mixed carbonate-hydroxides [4MgC03 Mg(0H)2-5H20] and [3MgC03Mg(0H)2-3H20] once employed for insulation. There are also other basic carbonates on the market with variations in adsorptive index and apparent density. Many of these are employed as fillers in inks, paints, and varnishes. 

Coke for the aluminum industry must be calcined before use to produce quality anode carbon. This calcined coke should be relatively hard, strong, dense, with low electrical resistivity and oxidation sensitivity, high purity, and available in aggregate sizing from -1 inch particles to cover standard anode filler sizing requirements. The desired range of property values is as as given in Table I. 

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