Foam impregnation

Targonski and Pielecki investigated the production of cellulase using immobilized mycelium of Trichoderma reesei mutants on polyurethane foam impregnated... 

Selective preconcentration of mercury(ll) and its organomercury compounds (e.g., methylmercury, phenylmercury) has been achieved by the use of polystyrene- and other resins, or polyurethane foam impregnated with zinc dithizonate, thio-HTTA [20], or dithizone [21,22]. 

The Pyrocatechol Violet method has been used for determining tin in biological materials [5], foods [5,89], organic substances [2], rocks and ores [12], copper alloys [90], and steel [33]. Traces of tin in water and in lake sediments were determined with the aid of PV and CTA after preconcentration on polyurethane foam impregnated with dithiol [91]. Tin was also determined by the PV method in alloys after extractive isolation with the aid of tris(2-ethylhexyl)phosphate [92]. 

For successful application, a technology has to be developed to bring the soot into contact with the catalyst without losing the catalyst during operation. Ceramic foams impregnated with a molten salt or dedicated catalyst/filter systems are thought to be promising candidates for this application. 

Lignolytic enzymes Phanerochaete chrysosporium Foam impregnated with nutrients [33]... 

The reactor core consists of a right circular cylinder of graphite foam impregnated with uranium carbide. The radius of the cylinder is 75 cm. The cylinder is divided into two zones—a central unpoisoned region having a radius of approximately 13 cm and an outer annular region in which the foam is impregnated with cadmium at a density of 86 mg/cm. The ratio is 39. The uranium (20% enriched... 

Bonding Web passes through a foam-impregnating machine and is wetted with a bonding... 

As shown in Fig. 10-7, widely different technologies are utilized to produce wipes. This is also applicable to the binder application method. The acrylic latex can be applied through saturation, foam impregnation or print bonding as shown in Tab. 10-3. 

Oligomeric 2-ChloroethylPhosphate. Akzo s Fyrol 99 [109640-81-5] is produced either by self-condensation of tris(2-chloroethyl) phosphate (82) or by insertion of phosphoms pentoxide into this phosphate (82) followed by ethoxylation. It is low in volatihty and useful in resin-impregnated air filters, in flexible urethane foam, rebonded foam, and stmctural foam. 

Stamp-Pad Inks. These inks are impregnated into a cloth or foam mbber pad and transferred by pressure to mbber type which is then stamped or impressed against the substrate. The inks must be completely nondrying in the pad and yet dry by rapid penetration into the paper. Since it is desirable that the total ink soak into the stock, dyes are used rather than pigments. The vehicles used are usually glycols. 

The rate of evolution of a toxie or flammable vapour from a liquid (e.g. in an open vessel, from a spillage or as a spray) is direetly related to the exposed area. Therefore, the rate of vapour formation from solvent-impregnated rag, from solvent-based films spread over a large area, from foams or from mists ean be many times greater than that from bulk liquid. 

This low pressure process, also known as elastic reservoir molding, consists of making basically a sandwich of plastic-impregnated open-celled flexible polyurethane foam between the face layers of fibrous reinforcements. When this plastic composite is placed in a mold and squeezed, the foam is compressed, forcing the plastic outward and into the reinforcement. The elastic foam exerts sufficient pressure to force the plastic-impregnated reinforcement into contact with the heated mold surface. Other plastics are used. 

The polishing pad, as another consumable material, also has a dominating effect in the CMP process, which is usually made of a matrix of cast polyurethane foam with filler material to control hardness of polyurethane impregnated felts. The pad carries the slurry on top of it, executes the polishing action, and transmits the normal and shear forces for polishing, thereby playing a very cnacial role in process optimization [44 6]. 

Cobalt-on-alumina catalysts with increased dispersion and catalytic activity are prepared by addition of mannitol to the cobalt nitrate solution prior to impregnation. Thermogravimetric analysis (TGA) and in situ visible microscopy of the impregnation solution show that the organic compound reacts with cobalt nitrate, forming a foam. The foam forms because significant amounts of gas are released through a viscous liquid. The structure of the foam is retained in the final calcined product. It is this effect that is responsible for the increased dispersion. 

Small foam pieces are impregnated with chicken, duck or turkey offal homogenate at the rate of 12.5 parts medium to one part foam by weight. A wide mouthed Erlenmeyer flask of 500 ml capacity is filled with this foam homogenate mixture to the 250-300 ml mark (about 100 g). The mouth of the flask is wiped, plugged with cotton, wrapped with cheese muslin cloth and autoclaved at 121°C for 20 min. 

It was possible to cover additional applications with these new types. In 1951 BASF found it was possible to impregnate polystyrene direct with expanding agents in the suspension process. This opened up great new possibilities for polystyrene foam (STYR0P0R, BASF, 33), for example in the packaging and building fields. 

Expandable PS beads are a material devised to accommodate the transportation drawbacks of foams. Foams take up a lot of room, but not much weight, so a truck or boxcar cannot be used very efficiently. Expandable PS beads can be readily turned into foam at their destination. The beads are impregnated with a volatile liquid like pentane as they are extruded, chopped, and cooled. Later, on site, the beads are heated in small batches with steam. The vaporization temperature of the pentane is just below the melting point of the PS beads. As the beads soften, the pentane flashes (volatilizes) and causes the PS to foam. The polymer is then ready for molding. Coffee cups, ice chests, life preservers, buoys, and floats are often fabricated this way. 

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