THE CHEMICAL WORLD THIS WEEK as one possible way of reducing book prices. The periodical literature was discussed by J. H. Bowman, Mellon, and D . O. Myatt, Industrial and Engineering Chemistry. Bowman resolved the functions of the journals into three categories. News functions he considered well served. He felt that publication of major advances was also reasonably successful, though he said that some means of emphasizing the outstanding papers was needed. The big problem he saw was the great volume of "fringe" papers, reporting valuable results, but of narrow interest to a few specialists. Myatt attributed the large recent increase in technical research and publication to the fact that modern industries are drawing upon science at an unprecedented rate. "Project" research characteristic of industry has imposed new burdens on technical personnel, some of whom need information from all fields of knowledge. Myatt expressed the belief
that the needs and financial resources of industry are leading to a major attack on the communication problem. He reviewed the recent editorial innovations in Industrial and Engineering Chemistry directed toward better communication of broad trends and significant developments. Problems of the Chemist. In his annual report to the Institute, retiring president Flett stated that the outstanding problems of the chemist were reorganized by the program of the meeting. The chemist needs to improve public relations, to promote safety, and to improve his relations with management. There is a serious problem approaching with regard to the chemical literature. There is currently a shortage of chemists for specific positions, Mr. Flett said. It is felt, however, that the major problem is the misuse of the chemist, and that there would be an adequate number of chemists available if they were all used to thenfull capability.
C&EN REPORTS:. Electrochemical Society
Textiles Without Weaving Look Good to Electrochemists Electrochemical Society celebrates its 50th anniversary . . . Reaction kinetics moves into electrochemical theory . . . Rare metals recovered PHILADELPHIA, PA.-The electrochemists celebrated their 50th anniversary with a record-breaking attendance of nearly 700 at their annual meeting here May 4 to 8. Nonwoven fabrics described in several papers before the recently formed electric insulation division of the society proved the high spot of the meeting for most of the members attending. These fabrics were variously developed as filtering media, insulators, or plate spacers and the electrochemists were professionally interested in their applications as electrical insulation or as spacers in electric batteries and condensers. However, they could not help but be intrigued by the possibilities of these materials as textiles for low cost clothing, leather substitutes, synthetic chamois, and a host of other applications. The newest and most revolutionary of the nonwoven fabrics discussed was made of 0.1 micron filaments of thermoplastic resins. V. A. Wente of the Naval Research Laboratory said that these materials were discovered in a search for a filtering material for military gas masks which would remove aerosol particles as small as 0.3 micron. No technique was known which would produce fibers of such small diameter so Wente developed a procedure in which the molten resin running from an orifice by gravity was stretched and ultimately cooled by a high velocity blast of 2084
high temperature air. The orifices need be only about 0.001 inch. The final diameter of the filament is determined by the velocity of the air stream. Although the original intent was to make a staple fiber it was found that the filaments were produced continuously and if they were allowed to fall on a moving screen they would form a cohesive mat. By adjusting the temperature of the air stream it is possible to deposit the fibers either fully hardened so that they do not adhere or in a tacky state in which they form a cohesive sheet. Natural turbulence in the air stream causes a random or tangled deposition of the fibers. Wente reported that the technique is equally effective with a wide range of plastic materials including several which have not previously been drawn into filaments. He mentioned nylon·, polyethylene, Dacron, Kel-F, polystyrene, and silicones. He spoke to the electrochemists particularly about the silicone fabrics as spacers in cells and transformers where silicone fluids are used as a dielectric because they would provide an electrically homogeneous combination of spacei and dielectric. The biggest deficiency of the materials at present, Wente said, is their lack of tensile strength. Most of the materials have tensiles under 200 pounds per square inch although this can be improved by CHEMICAL
hot calendering. Wente also said that the use of bonding resins may result in stronger fabrics. In general the strength of the fabrics increases as the diameter of the filaments decreases since the number of contacts between fibers increases as the reciprocal of the square of the diameter. The samples of nonwoven fabrics exhibited by Wente at the meeting resembled split leather as much as anything. They have a smooth, chamoislike texture and, unlike all other nonwoven fabrics, hang in natural folds to produce what textile people call an excellent drape. The materials are quite satisfactory for the filtering purposes for which they were developed and have shown considerable promise for the filtering of liquids, according to Wente. Their use in electrical applications is still experimental but shows promise. More fanciful applications as clothing fabrics will await further development work. Sheets from Ceramic Fibers The results of a more conventional approach to the problem of making a continuous sheet from nontextile fibers at the Naval Research Laboratory were reported by Thomas D . Callinan who worked with filaments made from a 50-50 aluminasilica melt by a process similar to that used for making rock wool. He said that the technique would work equally well with filaments from molten natural clay or refinery slag. He, too, was seeking fibers of small diameter and by collecting the fines from mineral wool by means of a series of riffle boxes he was able to obtain a material a micron or less in diameter and about 25 microns long. Because of what is apparently a static charge on these fibers they behave much like organic fibers as long as 0.5 inch. The fibers are processed in standard paper-making machinery. They are mixed with bonding resins in a beater or hydropulper, and the slurry is felted on a Fourdrinier. Equally successful sheets were made using bentonite clay rather than a resin as a binder. The resulting product is more like a paper than a fabric but it has considerably greater tensile strength than Wente's continuous filament mats, because it tears rather than pulls apart. Callinan recommended the ceramic paper, as he called it, for high temperature insulation—it melts at 2800° F.—and as exceptionally stable electrical insulation. The dielectric properties of the papers also recommend them for use as spacers in oil filled condensers, Callinan said. The speaker pointed out in closing that the common nature of the raw materials used for this sheeting combined with the ease of its manufacture ensure that it can be sold at a lower price than any comparable material including papers made from glass fibers. Still another new class of synthetic fabrics made by felting synthetic staple fibers with certain thermoplastic bonding fibers was discussed by Arthur Wrotnowski AND
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THE CHEMICAL WORLD THIS WEEK 400 to 6 0 0 kilowatts and ran 48 to 6 0 hours per run. The process used w a s a modification of the hot wire process w i t h heated graphite, hairpin rods substituted for the wire. T h e feed was a mixture o f five parts b y volume of hydrogen a n d o n e part of boron trichloride. Fetterley said that the operation w a s relatively successful and produced a product 9 7 % pure. However, he said that for regular commercial production both process and e q u i p ment could undoubtedly b e improved.
of die American Felt Co. By heat treating just enough to assure cohesion, a fibrous, nonwoven felt is produced which, Wrotnowski said, may I · useo as a base fabric for plastic laminates, as battery separators, electrolyte absorbent pads, electrical insulation, or as filter media. Various blends have been produced using asbestos, fibrous glass, dynel, saran, Orion, and vinyon. Different combinations are used for different application. Wrotnowski discussed mostly uses of the felts as bases for phenolic plastic laminates. Kinetics in Electrochemistry Most electrochemical theory in the past has been based upon thermodynamic calculations, but recent advances in instrumentation and in the academic training of electrochemists is leading to increasing attention to the reaction kinetics of electrochemical reactions. When n e w areas of theory are opened up, controversies are bound to arise and the nearly 50 papers presented before the theoretical electrochemistry division frequently initiated prolonged and intense discussions. The new ideas presented were obviously stimulating to the audience but they were not uniformly accepted at first hearing. George and Roberta Dubpernell of U. S. Rubber suggested that so-called "hydrogen overvoltage" is not caused by hydrogen at all but is due to the deposition of small traces of alkali metals on the electrode. They based their thesis on the fact that the back electromotive force of polarization corresponds closely to the electrode potentials of alkali metal alloys whereas no known form of hydrogen is capable of generating such high negative potential. Better measurements of this overvoltage were offered by S. Schuldiner of the Naval Research Laboratory, who offered a calculation by which the cleanliness of a bright platinum electrode could he confirmed during the determination. Another exploration of overvoltage effects was made by Thor Rubin of Ohio State who worked with copper anodes. He found that if he assumed that the distance the space charge extended into the solution was independent of the current density and was taken as the thickness of the Stern layer at the metal solution interface, it was possible to show a linear relationship between over-voltage and square root of the current density. A new theory of conductivity based on the study of fast electrode reactions by chronopolarography was advanced by J. G. Barredo of the University of Chicago. From his data he derived an equation relating current with the reaction and larger formation constants, the number of free radicals or atoms at the electrode surface, the order of the electrode reaction, time, effective voltage, resistance, and capacity. The equation reduces to Ohm's law when time equals zero. Another group from Ohio State led by A. B. Garrett proposed a mechanism for the reaction in photovoltaic cells consisting of metal electrodes in electrolyte solution.
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A. E. Winger, Rohm & Haas, said ionexchange membranes would soon b e available commercially; was besieged by questions when he left the platform T h e mechanism is postulated from the variations in spectral sensitivity of these systems and the effects of dissolved gases in the electrolytes. N o Agreement on Sign Convention One afternoon session of t h e ' division w a s devoted to a lively discussion of the proper sign convention to b e used when describing electric cells. In oversimplified form the controversy hinges upon whether the electrodes should b e labeled according t o the charge on t h e electrode or t h e charge in the solution immediately surrounding the electrode. At present the Electrochemical Society observes the classical or European convention; the AMERICAN CHEMICAL SOCIETY follows the Ameri-
can or Lewis convention. Generally texts written by physical chemists use the Lewis notation while books concerned with electric cells retain the older usage. However, some books actually use both conventions in different contexts. The result has been confusion not only for the student but for the practicing chemist as well. By the en
