Abstract: Insulating foam for refrigerators and the like is prepared by blowing in the presence of carbon dioxide as the sole or principal blowing agent. The thermal conductivity of the foam is decreased by sealing said foam in a gas-impervious enclosure with at least one getter, such as an alkaline material, capable of removing carbon dioxide and at least one drying agent which will produce a relative humidity greater than the equilibrium relative humidity over a saturated aqueous solution of the getter, thus removing water without rendering the getter anhydrous. For example, calcium chloride dihydrate may be used when the getter is sodium hydroxide.

Abstract: Low thermal conductivity insulation for refrigerators and the like is produced by blowing a resinous foam in an inert (e.g., nitrogen) atmosphere with a mixture of carbon dioxide and a low thermal conductivity inert gas such as krypton or xenon. The foam is then sealed in a gas-impervious enclosure and carbon dioxide is removed therefrom, typically by inclusion in said enclosure of a solid material reacted therewith such as an alkaline reagent. The final partial pressure of the low thermal conductivity gas in the enclosure is in the range of about 20-200 torr, and the total pressure is up to 110% of said partial pressure.

Abstract: Polyurethane foam of low thermal conductivity is prepared by employing carbon dioxide as a blowing agent, preferably in combination with a halogenated compound, typically a halocarbon or halohydrocarbon such as monofluorotrichloromethane or 1,1-dichloro-1-fluoroethane, and incorporating in the foam a carbon dioxide-reactive reagent. Sodium hydroxide and soda lime are illustrative carbon dioxide-reactive reagents. The carbon dioxide is preferably formed in situ by the reaction of water with the diisocyanate precursor of the polyurethane, and the carbon dioxide-reactivereagent is preferably introduced in admixture with a portion of the polyol precursor.

Abstract: Low thermal conductivity insulation for refrigerators and the like is produced by blowing a resinous foam in an inert (e.g., nitrogen) atmosphere with a mixture of carbon dioxide and a low thermal conductivity inert gas such as krypton or xenon. The foam is then sealed in a gas-impervious enclosure and carbon dioxide is removed therefrom, typically by inclusion in said enclosure of a solid material reacted therewith such as an alkaline reagent. The final partial pressure of the low thermal conductivity gas in the enclosure is in the range of about 20-200 torr, and the total pressure is up to 110% of said partial pressure.

Abstract: Polyurethane foam of low thermal conductivity is prepared by employing carbon dioxide as a blowing agent, preferably in combination with a halogenated compound, typically a halocarbon or halohydrocarbon such as monofluorotrichloromethane or 1,1-dichloro-1-fluoroethane, and incorporating in the foam a carbon dioxide-reactive reagent. Sodium hydroxide and soda lime are illustrative carbon dioxide-reactive reagents. The carbon dioxide is preferably formed in situ by the reaction of water with the diisocyanate precursor of the polyurethane, and the carbon dioxide-reactivereagent is preferably introduced in admixture with a portion of the polyol precursor.

Abstract: A simple process for producing expandable thermoplastic resin particles is provided wherein a desired amount of a blowing agent is added to a particulate thermoplastic resin in a closed vessel and the mixture is allowed to age at ambient conditions for a sufficient period of time to allow the resin to become impregnated with the blowing agent.

Abstract: A microporous plug is provided which serves to seal a vessel so as to prevent the bulk flow of gases through an outlet. The pores of said microporous plug are sized so as to permit the transport of gases to and from the vessel interior by Knudsen diffusion. In preferred embodiments, the pores of the plug are sized so as to release helium from the interior of a vessel and restrict the transport of carbon dioxide into the vessel from the surrounding atmosphere by Knudsen diffusion. Such embodiments are particularly useful on Mars where the helium is transported into an environment of higher pressure. In other embodiments, the microporous plug is used in conjunction with an absorber positioned within the vessel to react with atmospheric gases that pass through the plug, such as carbon dioxide. Also provided are radioisotope thermoelectric generators that incorporate a microporous plug and optionally an absorber.

Abstract: The use of fumed silica in a mixture of powdered silicon and cuprous chloride has been found to reduce agglomeration in a fluid bed reactor during the production of alkylhalosilane under continuous conditions.

Abstract: A method is provided for making alkylhalosilanes by effecting reaction between an alkyl halide, such as methyl chloride and powdered silicon in the presence of a copper-zinc-tin catalyst. Significant improvements in reaction rate and product selectivity are achieved when copper is employed at a critical weight percent relative to silicon and critical weight ratios of tin and zinc are employed relative to copper.

Abstract: A process is provided for making methylchlorosilanes based on the reaction of methylchloride and particulated silicon, which has been contacted with a mixture of partially oxidized copper catalyst and copper formate. A reduction is achieved in the percent by weight of residue which are the silicon products in the methylchlorosilane crude having boiling points exceeding 70.degree. C. at atmospheric pressure, while the weight percent of disilane in such residue cleavable to useful chlorosilane monomer is not adversely affected.

Abstract: A nuclear fuel material green body of density from about 30 to 70% of theoretical density having tensile strenght and plasticity adequate to maintain the integrity of the body during processing leading to ultimate sintered condition is produced by adding an amine carbonate or carbamate or mixture thereof to a particulate mass of the nuclear fuel material under conditions resulting in reaction with the amine compound to form a water-soluble compound effective as a binder for the particulate material.

Abstract: A nuclear fuel material green body of density from about 30 to 70% of theoretical density having tensile strength and plasticity adequate to maintain the integrity of the body during processing leading to ultimate sintered condition is produced by adding one or more amines to a particulate mass of the nuclear fuel containing about five percent of ammonium uranyl carbonate under conditions resulting in reaction of the amine with the ammonium uranyl carbonate, liberation of ammonia and formation of a water-soluble uranyl compound more effective as a binder than the ammonium uranyl carbonate.

Abstract: An ultrathin polyphenylene oxide/organopolysiloxane-polycarbonate copolymer film is described wherein the film contains from about 10 to about 35 percent by weight of the organopolysiloxane-polycarbonate copolymer.

Abstract: There is described the selective separation of a gas from a gaseous mixture utilizing a suitable ion-exchange membrane having specific counter-ions electrostatically retained therein, which counter-ions react reversibly with the specific gas molecules to be separated. By this method, the membrane exhibits high selectivity and facilitated transport of the gas across the membrane effecting superior separation of the select gas from the gas mixture.

Abstract: An improved method is described for the solvent casting of ultrathin non-porous membranes having surface areas of greater than one square foot. Film thicknesses of less than 200 Angstroms are routinely obtained, because the solidified film remains substantially free of tensile stress during the formation and removal thereof from the liquid casting substrate. The casting solution used comprises polymer dissolved in a solvent system and is characterized by being able to spontaneously spread over the surface of the liquid casting substrate. The casting solution is deposited in a narrow, longitudinally-extending defined region at the surface of the casting substrate; the surface area and perimeter of the defined region are enlarged over the surface of the casting substrate in a manner whereby only casting solution is moved relative to the casting substrate and, once desolvated, the polymer film formed remains stationary relative to the casting substrate and substantially free of tensile stress.

Abstract: A diagnostic device is described employing a solid, rigid diagnostic substrate (having as a part thereof an exposed layer of first immunologically reactive biological particles) in combination with means spaced therefrom for containing a solution of second immunologically reactive biological particles specific to the first particles. Preferably these elements are arranged with the layer of first immunologically reactive biological particles on a glass slide having a metallized surface and facing the containing means with spacing therebetween. This spacing defines a wedge-shaped volume for containing test fluid. With a test fluid in place, after allowing diffusion to occur for a predetermined period of time, the extent of formation of a layer of the second particles (i.e., a second layer) on the first layer is determined. If such a second layer develops, this determination can be related to the concentration of first particles in the test fluid.

Abstract: Hydrogen sulfide is removed from a mixture of gases including carbon dioxide by passing the mixture over an immobilized liquid membrane in intimate contact with a hydrophobic, microporous gas, permeable barrier and absorbing in a liquid solution hydrogen sulfide passing through the membrane. In a sweep of hot carbonate solution, a nearly stagnant boundary layer adjacent the gas permeable barrier absorbs acid gases by reaction and diffusion, maintaining low hydrogen sulfide partial pressure at the outlet side of the barrier. Alternatively, the sweep may comprise an aqueous solution containing a redox agent which converts absorbed hydrogen sulfide into sulfur, or an ethanol amine solution. The apparatus exhibits low permeability to carbon dioxide and high permeability to hydrogen sulfide.

Abstract: A film-grid composite substrate for supporting specimens in electron microscopy comprises a specimen-support grid adapted for electron microscopy and an ultrathin film of a mixture of organopolysiloxane-polycarbonate interpolymer and polyphenylene oxide. Regions of a major surface of the film are in contiguous relationship with a major surface of the grid, while other major surface regions of the film span apertures defined by the grid structure.

Abstract: Hydrogen sulfide is removed from a mixture of gases including carbon dioxide by passing the mixture over an assembly comprising a pair of immobilized liquid membranes of carbonate/bicarbonate solution separated by a gas permeable barrier of hydrophobic microporous material. Because hydrogen sulfide transport through the membranes is diffusion limited while carbon dioxide transport therethrough is reaction rate limited, the assembly exhibits reduced permeability to carbon dioxide and essentially unchanged high permeability to hydrogen sulfide compared to a single immobilized liquid membrane of thickness equal to total thickness of the membranes in the assembly. Hydrogen sulfide thus passes through the assembly more selectively than carbon dioxide.

Abstract: A method is provided for making alkylhalosilanes by effecting reaction between an alkyl halide, such as methyl chloride and powdered silicon in the presence of a copper-zinc-tin catalyst. Significant improvements in reaction rate and product selectivity are achieved when copper is employed at a critical weight percent relative to silicon and critical weight ratios of tin and zinc are employed relative to copper.