Cooling Impregnation

Antimony Oxide as a Primary Flame Retardant. Antimony oxide behaves as a condensed-phase flame retardant in cellulosic materials (2). It can be appHed by impregnating a fabric with a soluble antimony salt followed by a second treatment that precipitates antimony oxide in the fibers. When the treated fabric is exposed to a flame, the oxide reacts with the hydroxyl groups of the cellulose (qv) causing them to decompose endothermically. The decomposition products, water and char, cool the flame reactions while slowing the production and volatilization of flammable decomposition products (see Flaa retardants for textiles). 

Among continuous reactors, the dominant system used to produce parasubstituted alkylphenols is a fixed-bed reactor holding a soHd acid catalyst. Figure 3 shows an example of this type of reactor. The phenol and alkene are premixed and heated or cooled to the desired feed temperature. This mix is fed to the reactor where it contacts the porous soHd, acid-impregnated catalyst. A key design consideration for this type of reactor is the removal of the heat of reaction. 

Epilation is required for permanent hair removal. The most effective epilation process is electrolysis or a similar procedure. Epilation can also be achieved by pulling the fibers out of the skin. Eor this purpose, wax mixtures (rosia and beeswax) are blended with Hpids, for example, oleyl oleate, which melt at a suitable temperature (about 50—55°C). The mixture is appHed to the site (a cloth tape may be melted iato the mass) and after cooling is rapidly pulled off the skin. A similar process can be carried out with a tape impregnated with an aggressive adhesive. 

Such types of loads may require special design of capacitor elements and their dielectric impregnation, cooling arrangement, size of shell or surface treatment. For all these applications therefore it is important to know the actual operating conditions, behaviour and characteristic of the load and its duty cycle before selecting the capacitors. 

A NaY zeolite (Al/Si atomic ratio 0.41) was supplied by Shokubai Kasei Kogyo Ltd. After an evacuation at 673 K for 1 h (lx 10 Pa), the zeolite powder was exposed to a vapor of Mo(CO)5 or Co(CO)jNO at room temperature, followed by an evacuation at room temperature for 10 min to remove physisorbed metal carlxrnyl molecules on the external surface of the zeolite. Mo(CO)yNaY or Co(CO)3NO/NaY was sulfided in a stream of an atmospheric pressure of 10% HjS/Hj (0.2 dm min ). The sulfidation temperature was increased from room temperature to 373 K at a rate of 2 K min and kept at the tempeiatiue for 1 h. Subsequently, the temperature was increased up to 673 K at a rate of 5 K min and kept at 673 K for 1.5 h. After the sulfidation, the sample was cooled in the HjS/Hj stream to room temperature. The Mo and Co sulfide catalysts thus prepared are denoted MoSx/NaY and CoSx/NaY, respectively. Mo sulfide catalysts, MoSj/NaY, were also prepared by a conventional impregnation method by using ammonium heptamolybdate, for companson. 

Cools and Janssen [545] studied the effect of background salt on the permeability of warfarin through octanol-impregnated membranes (Millipore ultrafiltration filters, VSWP, 0.025-pm pores). At a pH where warfarin was in its ionized form, it was found that increasing background salt increased permeability (Fig. 7.7). This... 

Cools, A. A. Janssen, L. H. M., Influence of sodium ion-pair formation on transport kinetics of warfarin through octanol-impregnated membranes, J. Pharm. Pharmacol. 35, 689-691 (1983). 

A heating device softens the pre-impregnated rovings. Rollers consolidate the composite before passing through a cooled die to solidify the thermoplastic matrix. 

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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