Science: Synthetic Rubber

Many people know that most of Germany’s army trucks, armored cars, gun carriages and motorcycles roll on synthetic rubber. Fewer people are aware that throughout U. S. industry for some time synthetic rubbers-;expensive but highly resistant to oil, acid, sunlight, water-;have been doing many small jobs better than natural rubber can do them. Last week in the U. S. synthetic rubber made news on both these fronts when Standard Oil Co.

of New Jersey announced it was ready to make “buty rubber; B. F. Goodrich Co.

announced it would make tires of a new synthetic named “Americanpol” (see pg. 69).

In 1860 a British chemist named Greville Williams broke down natural rubber by distillation, obtained a hydrocarbon compound called isoprene. In 1882 William Tilden, also of Britain, made isoprene by .racking turpentine vapor in a red-hot tube.

The Germans, blockaded from the natural rubbers of Malaya and Ceylon, made some solid tires of synthetic rubber in World War I.

Polymerization (the process of linking molecules together in long chains) is the key to successful artificial rubber. In natural rubber such molecular chains hold the substance together when it stretches. When chemists stopped trying to duplicate natural rubber’s chemical composition, and set out to duplicate its structure and mechanical action, results followed.

Nieuwland & Neoprene. In 1900 the late Julius Arthur Nieuwland, Belgian-born chemist, Catholic priest and longtime teacher at the University of Notre Dame, made a poisonous black tar by treating acetylene with metallic chlorides.-At a scientific meeting in 1925 Nieuwland described one of his experiments producing acetylene rubber. A Du Pont chemist heard him, started his company on the trail. With Nieuwland’s collaboration Du Pont workers made a good rubbery material first called DuPrene, now neoprene, which is highly resistant to oil. Its dozens of uses include hose linings, gaskets, conveyor belts, rubber gloves, printing plates, refrigerator seals, hospital sheeting, sink scrapers.

Butadiene. Germany’s butadiene rubber (better known as “Buna”), which I. G. Farbenindustrie started to make commercially in 1936,15 versatile. Treated with one chemical, it becomes impervious to oil and heat; with another, it makes a tough, durable rubber for tires. Like neoprene, it is made from acetylene (a product of coal and limestone). It costs less than neoprene.

Goodrich’s “Ameripol” is a butadiene rubber, but it is made by cracking petroleum, of which the U. S. has plenty, Germany hardly enough. Cracking yields a gas, which liquefies to give butadiene under pressure. Standard Oil’s butyl rubber is also a butadiene from oil-cracking. Last year Chicago’s Universal Oil Products Co.

announced development of a process by which it expected to make butadiene rub ber from butane for only 20¢ a pound.

Thiolcol.” In the early 19205 Chemist J. C. Patrick of Kansas City, who was looking for a good anti-freeze mixture, mixed ethylene dichloride and sodium polysulfide, surprisingly obtained a gummy mass resembling rubber. Production of this stuff, now called “Thiokol,” got under way in 1931. The dichloride and polysul fide are mixed to form a white emulsion, in which rubbery lumps are coagulated by treatment with hydrochloric acid. “Thioko” is opaque, pale yellow, has an odor and low tensile strength, but resists chem ical deterioration and is insoluble in usual solvents. It is used to seal airplane fuel tanks, for gasoline hoses and nozzles.

“Koroseal.” Made from “All, coke and limestone, Goodrich’s” Koroseal” is usu ally classed as a plastic although it is a rubbery synthetic. It cannot be vulcan ized but can be made in any consistency from jelly-soft to bone-hard. Resistant to nitric and hydrofluoric acids, it makes good linings for pickling tanks in steel mills. It also goes into beer pipes, gaskets, waterproof fabrics, racks for holding parts to be coated in chromium plating baths.

-During World War I, Winford Lee Lewis, research director of the Institute of American Meat Packers, used this tar to make lewisite, a blistering liquid which military chemists say is worse than mustard gas. The war ended before any lewisite got into action at the front.