On 2nd November 1931, the DuPont company, of
Wilmington, Delaware, announced the first synthetic rubber. It was known as
DuPrene, and from 1936 as Neoprene. Many scientists were trying to make natural
rubber in the 1920s and 30s. One of the Wallace Carothers team, Gerard Berchet,
had left a sample of monovinylacetylene in a jar with hydrochloric acid (HCl)
for about five weeks.
Then on 17 Apr 1930, coworker Arnold M. Collins happened
to look in that jar and found a rubbery white material. The HCl had reacted
with the vinylacetylene, making chloroprene, which then polymerized to become
polychloroprene. The new rubber was expensive, but resisted oil and gasoline,
which natural rubber didn't. It was the first good synthetic rubber.
In 1935, German chemists synthesized the first of a series
of synthetic rubbers known as Buna rubbers. These were copolymers, meaning the
polymers were made up from two monomers in alternating sequence. Other brands
included Koroseal, which Waldo Semon developed in 1935, and Sovprene, which
Russian researchers created in 1940. B.F. Goodrich Company scientist Waldo Semon developed a new
and cheaper version of synthetic rubber known as Ameripol in 1940.
The production of synthetic rubber in the United States
expanded greatly during World War II, since the Axis powers controlled nearly
all the world's limited supplies of natural rubber by mid-1942 once Japan
conquered Asia. Military trucks needed rubber for tyres, and rubber was used in
almost every other war machine. The U.S. government launched a major (and
largely secret) effort to improve synthetic rubber production. A large team of
chemists from many institutions were involved, including Calvin Souther Fuller
of Bell Labs. The rubber designated GRS (Government Rubber Styrene), a
copolymer of butadiene and styrene, was the basis for U.S. synthetic rubber
production during World War II. By 1944, a total of 50 factories were
manufacturing it, pouring out a volume of the material twice that of the
world's natural rubber production before the beginning of the war. It still
represents about half of total world production.
Operation Pointblank bombing targets of Nazi Germany
included the Schkopau (50K tons/yr) plant and the Hüls synthetic rubber plant
near Recklinghausen (30K, 17%), the Kölnische Gummifäden Fabrik tire and tube
plant at Deutz on the east bank of the Rhine. The Ferrara, Italy, synthetic
rubber factory (near a river bridge) was bombed August 23, 1944. Three other
synthetic rubber facilities were at Ludwigshafen/Oppau (15K), Hanover/Limmer
(reclamation, 20K), and Leverkusen (5K). A synthetic rubber plant at Oświęcim
in Nazi-occupied Poland, was under construction on March 5, 1944.
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| World War Two poster about synthetic rubber tyres |
Solid-fuel rockets during World War II used nitrocellulose
for propellants, but it was impractical and dangerous to make such rockets very
large. During the war, California Institute of Technology (Caltech) researchers
came up with a new solid fuel based on asphalt mixed with an oxidizer (such as
potassium or ammonium perchlorate), and aluminium powder. This new solid fuel
burned more slowly and evenly than nitrocellulose, and was much less dangerous
to store and use, but it tended to slowly flow out of the rocket in storage and
the rockets using it had to be stockpiled nose down.
After the war, Caltech researchers began to investigate the
use of synthetic rubbers to replace asphalt in their solid fuel rocket motors.
By the mid-1950s, large missiles were being built using solid fuels based on
synthetic rubber, mixed with ammonium perchlorate and high proportions of
aluminium powder.
Such solid fuels could be cast into large, uniform blocks
that had no cracks or other defects that would cause non-uniform burning.
Ultimately, all large solid-fuel military rockets and missiles would use
synthetic-rubber-based solid fuels, and they would also play a significant part
in the civilian space effort.
Additional refinements to the process of creating synthetic
rubber continued after the war. The chemical synthesis of isoprene accelerated
the reduced need for natural rubber, and the peacetime quantity of synthetic
rubber exceeded the production of natural rubber by the early 1960s.
Nowadays synthetic rubber is used a great deal in printing
on textiles. In this case it is called rubber paste. In most cases titanium
dioxide is used with copolymerization and volatile matter in producing such
synthetic rubber for textile use. Moreover, this kind of preparation can be
considered to be the pigment preparation based on titanium dioxide.
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