Density filled grades

The bulk factor (i.e. ratio of the density of the moulding to the apparent powder density) of powder is usually about 2-3 but the high-shock grades may have bulk factors of 10-14 when loo.se, and still as high as 4-6 when packed in the mould. Powder grades are quite easy to pellet, but this is difficult with the fabric-filled grades. 

The properties of the main polysulfones are generally similar, although polyethersulfones have better creep resistance at high temperatures, higher heat-distortion temperature, but more water absorption and higher density than the Udel type materials. Glass fiber-filled grades of polysulfone are available as are blends of polysulfone with ABS. 

Enlite from DuPont Dow Elastomers is claimed to be the lowest density impact modifier for PVC on the market, and is targeted at the construction industry. The required dose is said to be low in highly filled grades of PVC. 

The properties of filled or reinforced grades of PE are strongly influenced by the type and the amount of filler (Tables 3.10 and 3.11). For example, the density of a heavily filled grade can be up to 50% higher than that of the unfilled material. 

Coal piles are carefully constmcted to exclude air or to allow adequate ventilation. The latter requites larger sizes, graded as 4 cm+ without fines, for a voiding heating by ventilation. For exclusion of air, mixed sizes provide fines to fill the gaps between larger pieces. Pockets of large sizes must not be allowed because these provide access for air. The coal should be compacted to maximize the bulk density of the coal pile. 

Prepare a solution of sodium silicate of density 1.06 by dilution of a good grade of the commercial article. Prepare also a supply of sulfuric acid approximately 3-normal. Pour 25 cc. of the dilute sodium silicate into an equal volume of the sulfuric acid and add 2 cc. of a 1 per cent solution of gold chloride, stirring well during the mixing. Divide the solution into two equal parts in test tubes that should not be more than about half filled and set the tubes aside in a cool place until a firm gel is formed. This may require upward of a week. 

Minipiles, those smaller in diameter than about 10 inches, function the same as larger piles. They are particularly suited in places where operating headroom is low, and where conventional pile driving equipment will not fit. They, too, will density granular deposits as they are driven. However, their small cross sectional area makes them unsuitable for (load bearing) sand piles. The smaller sizes, however, are filled with uncompacted, narrowly graded sand in clay deposits, to create sand drains. 

Test Procedures. Blow molded fluorinated and untreated bottles were filled with 370 grams of reagent grade toluene and heat sealed with a low density polyethylene-coated aluminum seal, and capped with a polypropylene closure. Ten sample containers of each type were tested at 50 2°C (50°C) and at room temperature (RT) for permeation and the onset of paneling. Empty containers, both treated and untreated, were also stored with the filled containers to serve as controls. 

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