Man's physical universe

xanabras

"BETTER THINGS" FROM CELLULOSE 669

Just as lacquers have partially displaced oxidizing oil

products for

finishes, various new fabrics are replacing the older materials produced

by the oxidation of linseed and other drying oils. Oilcloth is made by

coating a cotton base with linseed oil containing the desired pigment.

Linoleum is a somewhat similar product to which has been added

ground cork. Today canvas is coated or impregnated with pyroxylin

solutions containing materials to impart flexibility or color and to

produce durable fabrics, which are sometimes called "artificial leather"

or "leather cloth." Frequently they replace leather and are treated so

as to resemble leather. For many uses, such as book bindings, they

are not only cheaper than, but also superior to, leather.

When cellulose is further nitrated, a somewhat different cellulose

nitrate, called guncotton, is obtained. Guncotton, though a high

explosive, is too bulky, because it retains the original form of the

cotton from which it was made ; and it is too dangerous to use because

of its sensitiveness to shock.

In 1867 a Swedish chemist, Alfred Nobel, discovered that guncotton

would dissolve in warm nitroglycerine, which in itself is an excellent

explosive but difficult to handle because of its liquid state and too

great sensitivity to shocks.

It was found that the resulting mixture,

containing a little acetone and vaseline, was less sensitive and could be

used as a propellant powder. One such powder is the British "Cordite."

While smokeless powder may be made in this way, it is usually

made in the United States simply by "colloiding" the guncotton with

ether and alcohol to form a homogeneous and amorphous dough. This

dough is then forced through dies somewhat similar to a macaroni

machine, but which, in the case of cannon powder for example, have

seven axial perforations made in the cord. The cord is then cut off

into short lengths two or three times its diameter. These are then

dried to expel the solvent. Alfred Nobel also invented dynamite, which

is a mixture of nitroglycerine and sawdust or infusorial earth. It is

interesting to note that Nobel left his money, made from the invention

of these powerful explosives, to establish five world-famous

prizes in peace, literature, medicine and physiology, physics, and

chemistry.

Rayon dresses could be made from pyroxylin, but they would be

very dangerous to wear because, once ignited, they would burn very

rapidly. Methods have been found to remove the nitrate radicals

after the cellulose nitrate threads are formed so as to convert them into

cellulose, which is no more inflammable than cotton or other types of

rayon. This process is one of the less important rayon processes now

in use.

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