Shepherdstown register. [volume] (Shepherdstown, Va. [W. Va.]) 1849-1955, 1919-01-09


made its extensive applications posi-
bic. Just what takes place when sui
phur and rubber act upon each othe
even the chemist cannot say. W,
know only that some sulphur stays il
the rubber and that the properties o
the product vary with the amount o
sulphur thus retained. Vulcanizec
rubber is much less sensitive to chang,
OF temperature than crude rubber.
is impermeable to water and gases
and is an excellent electrical insulator
The more sulphur that rubber contain:
the harder il is. Ebonite, for example
contains from twenty-five to forty pei
cent of sulphur.
But yulcanation alone is not enough
to give to rubber the necessary proper.
ties for all purposes. II must be mix
ed with various substances to make
it tougher or sitter or more pliable
Those are, however, details with which
We need not occupy ourselves here.
The discovery of Goodyear of the ef'
feet of sulphur upon rubber is undoubt-
edly the most important discovery ever
made in the history OF rubber. At first
the world would have nothing to do
with the process. Again and again
Goodyear tried in vain to interest cap
italists in his invention, which he had
patented. He became embarrassed for
lack of money but finally New Haven
firm took the matter up and began to
manufacture rubber goods.
From that modest beginning the man
ufacture Of rubber products has grown
to be one of the great industries of the
world. The value Of rubber products
manufactured in the United States ir
1916 was nearly S300,000,000. OF
that more than one half goes to the ac-
count of tires.
What has the chemist been doing
meanwhile? He has not been idle, al
though rubber is an extremely difficult
substance to work with. In general
gums cannot be crystallized or distill-
ed without undergoing change in CONT
position, and so the chemist is hard put
to it to learn their secrets; for it id
only after purifying substance, by cry
stallizing or distilling them, that he
can tell definitely what he is dealing
with. Rubber may be ranked with the
gums, although, strictly speaking, gum
is perhaps not a correct designation
Ir belongs to the class Of substance
known as colloids.
Not much was learned about the
chemical nature OF rubber until 1860
At that time Greville Williams, study.
ing the products formed when rubber
is heated, found among those products
a liquid that he called isoprene. Most
of the recent efforts to make rubber ar
tificially have turned upon the use OF
that substance. 1t is hydrocarbons
that Is to say, it consists Of hydrogen
and carbon, as do many hundreds o
substances known to chemists
for example, as naphthalene, turpentine
and many Of the compounds in petro.
leum. In fact, rubber itself is by
drocarbon. But, whereas rubber can
not be distilled, isoprene boil; easily
and forms clear liquid.
In 1879 Bouchardat undertook a
thorough study of isoprene. He dis
covered, among other things, that wher
isoprene is heated with hydrochloric
acid, a product is formed that has the
same composition as isoprene, but tha'
differs markedly from itin its properties
Because that product apparently had
the properties of rubber Bouchardai
decided thar it was the same thing as
rubber; but the evidence he presented
was not conclusive.
Moreover, it is obvious that Bouchar.
dat's procedure could never become 2
commercial success. lsoprene could
at that time be made only from rub
Der, and in relatively small quantity
and the elastic, rubber-like substances
obtained from isoprene must, Of course,
be much more costly than rubber. Sc
that would not do. What next?
In 1882 Tilden showed that other
things besides hydrochloric acid have
the power to change isoprene into the
product described by Bouchardat, and
he furnished satisfactory evidence that
the product was the same thing as rub
Der. He went further and showed that
isoprene can be made by passing the
vapors Of turpentine through a hot
tube, although the amount Of the pro,
duct formed is relatively small.
If an economical method Of making
isoprene can be discovered, the problem
Of artificial, or synthetic, rubber will be
solved. II is toward that particular
point that the attack has been mainly
directed. Thanks to some excellent
work by foreign chemists, the chemical
structure Of isoprene has been made
clear. In other words, we now know
that it is the first condition for success
in our efforts to make it.
One starting point has already beer
suggested-turpentine. There is nc
doubt that isoprene can be made from
turpentine by heating the vapors to g
sufficiently high temperature, but the
process does not work we'll, and turpcn.
tine is not cheap enough, to warrant the
hope that this method can prove com.
mercially successful Another methoc
suggested consists in fermenting fuse