&toduct& €utcù ^toceèéed For ffurther u r t h e r information, i n f o r m a t i o n on any iitem tem m e n t i o n e d here fill o u t coupon on pp.. S56. mentioned
Gallium
Offered
Gallium is being produced and sold by Aluminum Co. of America. This rare metal is liquid at 86 ° F., but it will not boil until heated to approximately 3,700° F. Gallium shows a strong tendency to undercool, and the liquid metal may be held for some time at temperatures almost as low as the freezing point of water without solidification taking place. Though similar to aluminum in its chemical behavior, gallium is not a light metal. Its density (5.9) is about twice that of aluminum, but only about half that of metallic mercury. Like water but unlike most elements the density of gallium is greater as a liquid than as a solid; gallium actually expands on solidifying. It wets many types of nonmetallic surfaces,· such as glass and porcelain. As in the case of aluminum, a protective natural oxide film forms readily on the surface. Even when heated to temperatures as high as 1,000 ° F., a globule of gallium will remain bright and shiny. This combination of properties should make possible a variety of unusual applications for gallium. Traces of gallium are found in a variety of ores and minerals, but it is being derived by Alcoa from bauxite. It is estimated that the bauxite from which aluminum is extracted contains only about one ounce of gallium per ton. Separation and recovery of such minute quantities is a difficult and expensive task. The low concentration of gallium in ores, and attendant difficulties of production, have been a hindrance to the development of uses heretofore. Ρ 1
strength, low temperature, flexibility, and resistivity are desired. Ρ2
Phenolic
Glass
Laminate
The Panelyte division of St. Regis Paper Co. announces the production of a glass phenolic laminate which, according to the company, tests show is superior to any similar laminate now on the market. To be known as Grade 170, the laminate is extremely low in water absorption with a value of 0.06%; low in power factor, and exceedingly high in flexural and impact strength, as measured by ASTM methods. Considerable interest already has been expressed in Grade 170, specifically be cause of the very low water absorption and high strength. It is said that this grade may eliminate the necessity of antifungus treatments and other special handling now required for use in equipment in tropical climates and under high humidity conditions. Grade 170 will be produced in standard sheet sizes of 36 b}r 36 and 36 by 48 inches, natural color, semigloss finish, thicknesses ranging from 1/32 to 2 inches, writli a standard NEMA tolerance for Grade G-3. Following are properties for Grade 170: Tensile strength Flexural strength Bonding strength Impact strength Density Water absorption Dielectric strength Power factor Dielectric constant Loss factor
52,000 69,000 1,900 37 (flat), 18 (edge) 1.78 0.06 580
0.006 4.45 0.027 Ρ3
Plasticizers for Vinyl Resins
Radium-Beryllium Neutron Sources
American Cyanamid Co. has recently added to its line of organic chemicals the dioctyl phthalates, di-2-ethylhexyl phthalate and di-isooctyl phthalate, which will be marketed under the trade names AERO DOP and A E R O DOPI. These plasticizers are said to be well suited for compounding vinyl resins into films. They have low heat loss, a low brittle point, and good compatibility. They re main liquid down to temperatures as low as —55° C , thus keeping the vinyl film flexible over an extreme temperature range. Their outstanding electrical prop erties are said to make them excellent for use in vinyl wire coatings. The}' are also good plasticizers for nitrocellulose and synthetic rubber where high tensile
The United States Radium Corp. announces the availability of new and im proved radium-beryllium neutron sources. Investigations have resulted in preparation principles and techniques which have pro duced sources showing marked improve ment in the neutron to gamma emission ratio, according to the company. Quantitative measurements of neutron emission are not yet available, but com parative measurements with standard commercial sources indicate a major im provement in neutron output, the com pany said. New production techniques also have improved duplication of results, so t h a t buyers can now obtain sources that do duplicate in neutron emission. Sources can be provided in a powdered
V O L U M E
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NO.
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> » FEBRUARY
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1949
radium-beryllium mixture or a compressed radium-beryllium mixture, in any size, from a few milligrams' content for college laboratory routine experimentation, to 1,000 or more milligrams for special appli cations. Packaged in stainless, steel or magnetic iron capsules, all sources are made to order, and the design or shape of the container can be adjusted to meet special requirements. Standard polo nium-beryllium sources are also available, and special sources employing beta or gamma activated beryllium can be pro duced by arrangement. Ϊ* 4
Percolation
Clay
Attapulgus Clay Co. is offering the petroleum industry a granular highefficiency fullers earth for percolation-filter house use. Refining efficiency of the new clay—designated as Attapulgus AAA grade—has been established in extensive tests and commercially proved by use in one of the larger oil refineries in the coun try. Claimed for AAA is its ability to re duce clay costs since, with most oils, it displays 10 to 20% more refining efficiency and maintains this increase over its life. It thereby becomes practical to reuse it through more cycles; thus clay costs are p 5 cut 15 to 2 5 % .
Lotv-Cost Molding
Phenolic Powders
A group of general purpose phenolic molding powders which it is claimed will enable the plastics industry to achieve lower material costs with little or no sacri fice in the properties of high-quality molded parts, has been developed by General Electric Co. chemical department. The four compounds—black and brown for compression and transfer moldinghave a specific gravity of 1.37, and are said to have flow characteristics, cure time, and water resistance nearly equal to more costly wood flour-filled phenolics. Although the new materials do not have a high gloss on long-draw moldings and may show a slightly less rigid discharge from the mold, tests by General Electric indicate that they are highly satisfactory for the majority of thermosetting plastics applications. '' ^
Toxaphene as Common
Accepted Name
The word toxap e has been accepted as a coined commo~ name for the insecticidal chemical referred to as chlorinated camphene having a chlorine content of 67 to 69%. Acceptance of the term was made possible through action taken by the Hercules Powder Co. to relinquish its trade name Toxaphene. Acceptance of the name was reported by the American Association of Economic Entomologists in December. Ϊ* ? 553
