Expander compositions

Patent Number US 5801208 A 19980901 BLOWING AGENT, EXPANDABLE COMPOSITION, AND PROCESS FOR EXTRUDED THERMOPLASTIC FOAMS Shau-Tarng Lee Sealed Air Corp. 

Patent Number WO 9417133 A1 19940804 EXPANDABLE COMPOSITION AND PROCESS FOR PRODUCING EXTRUDED THERMOPLASTIC FOAM... 

NOESY) sequence (see Fig. 26D, Table 3), which was computer-optimized by Kadkhodaei et al. (1993), is based on the MLEV-16 expanded composite pulse R = 15° 75°, 279°45°. In the TOWNY sequence, a 2 1 ratio of and is achieved by the created trajectory of z magnetization during the course of the optimized phase-alternated composite pulse R, without the need for additional delays or modulation of the rf amplitude. Clean Hartmann-Hahn mixing sequences based on shaped pulses were developed by Mayr et al. (1993). The parameters of the shaped MW-1 sequence (Mayr and Warren, 1995) are given in Table 3. 

By virtue of its well-established nature in a number of industries, scalability, and excellent process control, melt extrusion meets the needs of both biotechnology and small molecule discovery pipelines. Combining this with an ever-expanding compositional knowledge for the technology, melt extrusion will make a clear difference in the future of drug delivery. 

S.T. Lee, Expandable composition and process for extruded thermoplastic foams, US Patent 5 462 974, assigned to Sealed Air Corporation (Saddle Brook, NJ), October 31,1995. 

Thereby, Au is the unit-cell area and corrects the flux normal to the surface to the direction of diffraction. The reader should note that not aU atoms of the layer must reside in one plane, so that the formula can also be appHed to vertically expanded composite layers. 

The previous equation is only valid as long as there is no compositional change of the gas between the subsurface and the surface. The value of E is typically in the order of 200, in other words the gas expands by a factor of around 200 from subsurface to surface conditions. The actual value of course depends upon both the gas composition and the reservoir temperature and pressure. Standard conditions of temperature and pressure are commonly defined as 60°F (298K) and one atmosphere (14.7 psia or 101.3 kPa), but may vary from location to location, and between gas sales contracts. 

Eoamable compositions in which the pressure within the cells is increased relative to that of the surroundings have generally been called expandable formulations. Both chemical and physical processes are used to stabilize plastic foams from expandable formulations. There is no single name for the group of cellular plastics produced by the decompression processes. The various operations used to make cellular plastics by this principle are extmsion, injection mol ding, and compression molding. Either physical or chemical methods may be used to stabilize products of the decompression process. 

Thermal Properties. Refractories, like most other soHds, expand upon heating, but much less than most metals. The degree of expansion depends on the chemical composition. A diagram of the thermal expansion of the most common refractories is shown in Figure 1. 

Sihcate solutions of equivalent composition may exhibit different physical properties and chemical reactivities because of differences in the distributions of polymer sihcate species. This effect is keenly observed in commercial alkah sihcate solutions with compositions that he in the metastable region near the solubihty limit of amorphous sihca. Experimental studies have shown that the precipitation boundaries of sodium sihcate solutions expand as a function of time, depending on the concentration of metal salts (29,58). Apparently, the high viscosity of concentrated alkah sihcate solutions contributes to the slow approach to equihbrium. 

Erequenfly, the term compressed fluid, a more general expression than supercritical fluid, is used. A compressed fluid can be either a supercritical fluid, a near-critical fluid, an expanded Hquid, or a highly compressed gas, depending on temperature, pressure, and composition. 

Expandable VDC copolymer microspheres are prepared by a microsuspension process (191). The expanded microspheres are used in reinforced polyesters, blocking multipair cable, and in composites for furniture, marble, and marine appHcations (192—195). Vinylidene chloride copolymer microspheres are also used in printing inks and paper manufacture (196). 

Fig. 5. Lead—Acid battery grid design variations showing A lugs, B feet, C frames, and D current carrying wire for (a) rectilinear design, (b) corner lug radial, (c) center lug radial, (d) corner lug expanded metal, and (e) plastic/lead composite.

Because these alloys are precipitation hardenable, they can be customized for specific requirements across a wide range of property combinations. Advances in composition control, processing, and recycling technology have broadened the capabiUties and expanded the range of appHcation. Data sheets pubhshed by the manufacturers and others (41) give compositions, properties, and typical appHcations. 

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