Resins Led Parade . . .
This Argonne team's data on neutron decay fall in line with earlier disproval of parity conservation. Clockwise: Victor Krohn ( b a c k to c a m e r a ) , Merle T. Burgy, G. Roy Ringo, and Theodore B. Novey
chemistry in 1957 was establishing yields of products when a substance is irradiated. As examples, water gives hydrogen atoms and hydroxyl free radicals plus molecular hydrogen and hydrogen peroxide; small paraffins involve loss of a hydrogen. Next step, a major project for 1958, is to learn more about intermediates in irradiated systems, together with rate constants. And if transients can b e spotted, as with iodine in some systems, their rate constants can be determined, say Argonne experts. Moreover, researchers are trying to correlate yields with energy input—a phase that could mean a lot to radiation chemistry's industrial future. Some new work in 1957 includes introduction of the carbonyl bond in proteins like pepsin and gelatin. This represents a principal chemical effect of irradiation. Another find is that irradiating hydrocarbons adsorbed on silica gel produces products different from those usually found. In one researcher's opinion, this suggests a new usefulness in the field, and 1958 work will be aimed at tying in catalysis studies. Of more immediate significance are 1957 results with irradiating plastics. Apparently, treating a polymer like polyethylene with ionizing radiations increases its chemical reactivity. This may be due to retention of free radicals within the resin body, and it permits making graft polymers. But, says an East Coast expert, there may remain a residue of low molecular weight matter which could "gum things u p . " But irradiated plastics still have properties 88
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that can't be obtained any other way. • Fusion Clouded. W h a t may b e one of 1957's most significant research results in t h e attempt to harness fusion p o w e r was clouded by international politics. T h e British experiment in producing fusion will be repeated in the U. S. and other countries. Just h o w big a breakthrough it is may be decided in 1958. Other paths to fusion power will also b e followed, as they have been for several years. Foundation for fusion studies can also be found in elementary particles. In t h e 1920's and 30's, work with particle accelerators showed that nuclear electrical repulsion forces can be broken and the projectiles forced to fuse with light target nuclei. Thermonuclear fusion is now a part of magnetohydrodynamics (theoretical hydromagnetics) which grew out of wartime fission work. A lot of today's research emphasis is on the pinch effect and associated instabilities, according to E d w a r d Teller. Pinch effect is the only declassified approach to fusion power. It occurs when an electric current passes through a conducting gas in a tube, creating a magnetic field which pulls t h e gas away from the tube walls. Instabilities, here, says Richard F . Post of University of California's Radiation Laboratory, are of two types. One happens when a small kink in t h e column develops. T h e other is a "sausage" instability—the gaseous plasma necks off a t one or more points and cuts itself up. Consensus is that no simple 'way to control fusion will be found suddenly, b u t only by difficult experiments all over the world.
. . . in 1957 as polycarbonates, polymers of ethylene oxide, polyformaldehydes turned up among new chemicals SINS
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widespread interest among n e w chemicals in 1957, with polypropylene causing perhaps the biggest splash. Late in the year, Hercules started u p t h e first commercial plant (20 million pounds a year) in the U. S. at Parlin, N. J., and Montecatini is now making 15 million p o u n d s a year in Italy. Promising, b u t not so far along, is General Electric's Lexan, a polycarbonate polymer. Pilot plant amounts will be offered for evaluation shortly, with commercial production perhaps a couple of years away. Lexan has a specific gravity of 1.2, and is said to be tough enough to replace metals for some uses. Dimensional stability, heat resistance, and nonflammabihty are further advantages. Still another new class of resins, high polymers of ethylene oxide, was introduced b y Union Carbide in 1957. Called Polyox, the new resins are water soluble and highly crystalline. They can be cast, calendered, or extruded into tough, flexible films. They resemble polyethylene except for water solubility and melting point (65° C ) . Carbide foresees uses in textiles, thickeners for colloids, stabilizers, and oneshot film packaging. In the latter, such things as detergents might b e packaged as a premeasured unit which would be dissolved when added to water. Formaldehyde turned up in a new type of resin, called Delrin. It's a thermoplastic polyformaldehyde developed by Du Pont, which is now building a commercial plant at Parkersburg, W. Va. Delrin can be molded or extruded, and is expected to complement Du Pont's line of Zytel nylon resins. • Ur e t h a n e s Draw Fire. Urethane foams were targets for numerous new
products in 1957. Polyethers w e r e perhaps the most profuse of the n e w candidates; they compete chiefly with polyesters, already well entrenched as raw materials for urethane foams. Wyandotte Chemicals started it off in January by introducing two series of compounds, one b a s e d on its Pluronic polyether glycols, the other on its Tetronic series of nonionic surface active agents. These polyethers are block polymers based on propylene and ethylene oxides, with molecular weights of from 2000 to 6000. I n October, Union Carbide brought out four new polyethers for urethane foams. T r a d e named Niax, they are adducts of propylene oxide and hexanetriol. And D o w is now in volume production of a n e w family of trihydroxy polypropylene glycols, including a special grade aimed at urethanes. Kmery Industries, meanwhile, got its polymerized fatty acids under way for use in polyesters to be used in urethanes. Properties of the resulting foams compare well with those of foams based on polyethers, E m e r y says. • Sugar Takes Hold. N e w chemicals based on sugar popped up in several places in 1957. D o w Chemical came out in mid-year with a crosslinking agent, based on sugar, for urethane foams. Called Hyprose SP80, it's octakis ( 2-hydroxypropyl ) sucrose, and is m a d e by reacting propylene oxide with sucrose. D o w said it might
be only the first in a series of similar compounds. Hyprose SP80 serves also as a plâsticizer in cellulosics, phenolformaldehyde resins, a n d the like. This month, Colonial Sugar will p u t a pilot plant on stream at Gramercy, La., to make sucrose monoesters for food a n d industrial uses. In April, Berkeley Chemical brought out Sucrodet D-600—recrystallized sucrose dipalmitate—a surface active agent and said it p l a n n e d to introduce sucrose esters derived from stearic, oleic, myristic, and lauric acids. And Pfizer is expected to announce substantial plans for sugar esters soon. Development of sugar-based resins was reported nearly a year ago b y Henry B. Hass of Sugar Research Foundation. And a few weeks ago, Valentine Sugar started pilot operations on sugar-formaldehyde resins, which are clear, pale amber products. They're said to have cost advantages, and Valentine is evaluating them "all the way through" for such uses as adhesives and molding compounds. Universal Oil Products and Corn Products Refining also stepped into a new field of sugar chemicals. A process developed by U O P reacts familiar hydrocarbons (toluene, xylene, phenol) with common carbohydrates (sugar, starch, cellulose). Corn Products is offering laboratory samples of resulting products, which include l-deoxy-1,1di-(o-xylyl)-D-glucitol and l-deoxy-1,1-
Boron nitride, otherwise known as borazon, now rivals diamond as the world's hardest material. It was synthesized by the same high-pressure team at General Electric that synthesized diamonds a couple of years ago. Big a d v a n t a g e is that borazon resists heat better, can be used in cutting tools running a t higher speeds
di- ( p-hydroxyphenyl ) -D-glucitol. Proposed uses for the r a n g e of possible products include detergents, plasticizers, resins, germicides, and others. Trick of the process is use of anhydrous hydrogen fluoride as a condensing agent. > Silicones Keep Coming. General Electric and Wright Air Development Center announced in November their development of a silicone-basecl hydraulic fluid ( C E 8 1 7 1 7 ) , designed for use above 450° F. At the same time came G E 81644, a silicone-based engine oil that remains stable to oxygen at up to 510° F . Both products are basically polychlorophenyi methyl siloxane polymers. Last summer, D o w Corning announced its Syl-Kem 21— pentamethyldisiloxanemethyl methacrylate—an organo-functional silicone. It undergoes many reactions typical of methacrylate esters, and can b e used to make polymers and copolymers with unusual bonding and surface characteristics. It polymerizes readily, says D o w Corning, in bulk, emulsion, or suspension to give a clear, tough plastic with a molecular weight of from 600,000 to 700,000. Elsewhere, Union Carbide launched a vinyl silane ester (Silane A-172) and an amino silane ester ( A - 1 1 0 0 ) , both for treating glass cloth and fibers used in reinforced plastics. T h e vinyl silane has shown good results with polyester resins, says Carbide, while the amino silane provides a chemical coupling agent that extends its usefulness to phenolic, epoxy, and melamine resin systems. Among elastomers, General T i r e introduced a polyurethane rubber which it feels is the strongest one yet developed for use in mechanical goods. Called Genthane S, it's oil- and ozoneresistant a n d is stable at high temperatures. It's rubbery at —40° F . . and not brittle or crystallized at —100° F. G E , meanwhile, brought out a silicone rubber (SE-555) with unusually high tear strength. GE, which began making synthetic diamonds commercially in 1957, used some of t h e same techniques to make borazon, a dense form of boron nitride. It's nearly as hard and nearly as heavy as diamond, and remains hard at temperatures where diamond b u r n s up. This temperature resistance, among other things, should m a k e borazon useful in industrial grinding equipment operating at higher speeds than in the past. JAN.
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