GLASS in the Atomic Age (Dec, 1946)
GLASS in the Atomic Age
World’s oldest plastic will shield health and machines.
THE PET idea of self-styled camouflage experts early in the war was to build warplanes of glass so that they could not be seen. Glass airplanes never flew, but glass is being used, because of its strength, in airplanes, artificial arms and legs, bulletproof armor, arctic clothing, boats and canoes, fertilizer, surgical bandages and fillings for teeth. One large glass company now is producing glass in more than 4,000 different forms and has experimental projects covering some 300 more potential uses.
The world has passed progressively through a Stone Age, a Bronze Age and a Steel Age. Glass experts believe that we now are entering a Glass Age.
A major glass-research program at the University of Pittsburgh, directed by Dr. Alexander Silverman, head of the University’s chemistry department, is aimed at the solution of some of the age-old secrets of glass. By using radio-isotopes as tracers, Dr. Silverman hopes to find out how the raw materials in glass melt, how the glass flows during meltingâ€”and what causes defects in glass. His findings may take many of the “ifs” out of glass manufacturing and open important new fields for future re-search regarding the world’s oldest plastic. A firm believer in a Glass Age, Dr. Silverman foresees great advances within five years. One of his most spectacular prophecies is that glass will be used as a defense against the atomic bomb. The same element that is used to make the bomb-uraniumâ€”can be used to produce a glass that provides good protection against harmful radiations. Garments and helmets made of cloth spun from uranium-glass or lead-glass fibers, says Dr. Silverman, would permit safe entry into atom-bombed areas. Special oxygen respirators, equipped with glass-insulated high-frequency precipitators, would keep radioactive dust out of lungs of rescue workers.
One of the most important recent glass-fiber developments is the perfection of a method for reinforcing other plastics with glass, just as we reinforce concrete with steel rods. Glass-reinforced plastics have many metal-like qualities, yet can be fabricated easily and inexpensively without complicated dies or high-powered presses. Almost as light as aluminum, they have the strength of many of our stronger structural metals. Designers and engineers are finding them ideal for use in molding railroad-car, bus and automobile bodies, airplane fuselages and parts, boats and canoes, fishing rods, luggage, football helmets, artificial arms and legs, furniture, kitchen and bathroom assemblies and home appliances.
Fabricating a glass-reinforced plastic product is like making a layer cake or using a pressure cooker, and almost as simple. The process is similar to that used in making low-pressure laminated plastics, except that glass cloth is used in place of plywood, sisal or paper as the filling for the plastic sandwich (PSM, May ’46, p. 122). Successive layers of glass-fiber cloth, impregnated with the desired liquid plastic, are simply laid one on top of the other in a form, or mold, of the desired shape. When enough layers have been built up to obtain the required thickness and strength, heat and pressure are applied in an autoclave that resembles a giant pressure cooker.
Technologists are devising all sorts of new uses for glass cloth and glass fibers. The same qualities that have made glass cloth valuable as heat-insulating material for use in buildings, bus tops and airplane cabins are now being put to use in new arctic clothing being tested by the U. S. Army. Field jackets, parkas, boots and mittens lined with glass cloth are expected to give good lightweight protection against subzero temperatures. An experimental glass-cloth-lined parka, worn by an observer during the recent Operation Musk Ox in northern Canada, afforded complete comfort at temperatures as low as -40 degrees F.
Glass-reinforced plastics also have made possible a lightweight bulletproof body armor for soldiers, which surpasses metallic armor in ballistic efficiency. Doron, as the glass-plastic armor is called, will stop missiles up to and including a .45-caliber revolver bullet. At the moment, Doron-ar-mored jackets are undergoing rigid tests in the jungles of Colombia. Eighteen jackets have been supplied to American scientists and drill crews of an oil company, several of whose employees have been wounded by natives.
Other experiments under way include the use of milled glass fibers as a reinforcing agent for special papers, as a material for strengthening phonograph records, and as an ingredient of paint to improve its sound-deadening qualities. It is even being used in yarn form by dentists to fill the root canals of teeth. Surgeons also are turning to glass yarn and cloth for sutures, special bandages and filters for blood plasma.
In the future it may even be possible to fertilize your garden by sprinkling the ground with glass wool. In an experimental process being developed by Drs. Alfred E. Badger and Roger H. Bray at the University of Illinois, a special glass containing the principal plant foods is so mixed that it is soluble in water and dissolves slowly in the soil, giving off chemicals necessary for plant life. By altering the composition of the glass, the rate at which it dissolves can be controlled. In this way, one application of the glass fertilizer can be made to serve over a period of several years.
Science has not only learned how to do new things with new glass, but it has learned how, by the use of special coatings, to improve the older conventional forms of glass. One is the new transparent and durable electricity-conducting coating that can be applied to windshields of airplanes and automobiles to eliminate the dangers of icing and fogging (PSM, Oct. ’46, p. 92).
Uncle Sam now leads the world in glass technology. Even in the field of optical glass, long dominated by Germany, we now excel, according to the Bureau of Standards. As research continues, the miracle of glass will continue to unfold. Glass as a material is thousands of years old. But glass as an industry is just coming of age.