Are you interested in the origin of the tire industry? Or the method of obtaining natural and synthetic rubber or even the invention of the tire itself? If this is the case, read this article and quench your curiosity.
تایر، the tire is a product made on American soil. But it has been developed to this extent through its cultivation in the Far East. The name Rubber, which means eraser, was given by Priestley, the discoverer of oxygen. He was the first person who observed the ability of rubber to erase the effects of materials. Rubber was the result of refining and preserving materials such as Ephethion, Butadiene, and Isoprene. Substances extracted from natural rubber’s destructive distillation. And such a process paved the way for the production of synthetic rubber.
At the beginning of the First World War, Germany and Russia were the sole producers of low-grade types of Dimethyl Butadiene tires. But it was the Goodyear that rose to fame with the discovery of curing rubber with sulfur in 1839. The discovery solved the problem of the natural stickiness of rubber and made it commercial. The USA restricted the import of natural rubber to America due to the invasion of the Japanese forces in 1941. This move led to the research and production of synthetic rubbers in the following years and changed the course of tire production forever.
Method of obtaining natural rubber
The two first commercially successful synthetic rubbers, Neoprene and Thiocol, were both produced by accident. Chemists learned about the molecular structure of rubber by heating it under controlled conditions and identifying the fragments from its decomposition. One of these fragments was Isoprene which is a five-carbon compound with two double bonds. In 1920, Hermann Staudinger wrote a famous paper explaining the structure of natural products such as rubber, cellulose, and proteins. As well as some synthetic materials that had similar properties. In his opinion, these substances, which were mysteriously different from simpler organic compounds, were polymers (the word is derived from the two Greek words poly, meaning several, and mer, meaning par or piece). Polymers are made out of large molecules in which repeating units are linked together by the same type of chemical bonds found in simpler compounds. As an example, the formula of the rubber molecule is suggested as follows: It was assumed that a large number of Isoprene “monomer” units (a fragment) in the rubber tree are connected during biological reactions and large rubber polymer molecules are produced.
The newer method is the conversion of the coagulated sap into grains by rotating blades or cutting between two rotating rollers at different speeds. The seeds are then dried in mechanical dryers for several hours, a process that would have taken several days in the old method that used air or wood smoke to dry. As a result, a dense and dry sheet produces and is moulded into 33 kg blocks. Rubber mixes with sulfur, carbon black, oil (softening agent), a delaying agent and other materials in a specialized mixer called Banbury (named after its inventor). The mixing process completes in about 6 or 7 minutes. The result is taken out of the mixer and rolled into sheets for cooling. Then more operations ought to be performed on the product, and the temperature should not increase. Otherwise, the mixture will be vulcanized, and the progress of the process becomes impossible. In the final stage, when the rubber (tire, carpet, ball, etc.) forms, it is heated (vulcanization), and the sulfur molecules connect with the rubber chain molecules, and the rubber takes on an elastic shape. It has to be mentioned that the vulcanization process is irreversible.
So to this day, we haven’t been able to recycle sulfur and rubber from used tires.
Some natural rubber is marketed as leachate. Before the rubber mixes with all kinds of necessary additives such as carbon black (as a filler), sulfur or sulfur compounds, accelerator and vulcanizer, protective antioxidant and oil on the same rollers or mixer, it may be as high as a two-story building. But only a small amount of rubber can be processed at a time. A sample mixer may be as tall as a two-story building and yet only handle 250 kg packages. After mixing, the rubber is formed into the desired product shape by punching or moulding and then it is baked. After vulcanization, a hard polymer is produced that doesn’t soften upon reheating and doesn’t melt.
The two first commercially successful synthetic rubbers, Neoprene and Thiocol, were both produced by accident.
Chemists learned about the molecular structure of rubber by heating it under controlled conditions and identifying the fragments from its decomposition. One of these fragments was Isoprene which is a five-carbon compound with two double bonds. In 1920, Hermann Staudinger wrote a famous paper explaining the structure of natural products such as rubber, cellulose, and proteins. As well as some synthetic materials that had similar properties. In his opinion, these substances, which were mysteriously different from simpler organic compounds, were polymers (the word is derived from the two Greek words poly, meaning several, and mer, meaning par or piece). Polymers are made out of large molecules in which repeating units are linked together by the same type of chemical bonds found in simpler compounds. As an example, the formula of the rubber molecule is suggested as follows:
It was assumed that a large number of Isoprene “monomer” units (a fragment) in the rubber tree are connected during biological reactions and large rubber polymer molecules are produced.
After the proposition of this formula for natural rubber, scientists made many efforts to prepare a type of synthetic rubber with the molecular structure and elasticity of tree-derived rubber. Thus, isoprene was exposed to various catalysts to see if it would polymerize into something like rubber. These efforts were successful enough to prove Professor Weidinger’s theory was correct. But the more detailed aspects of the molecular structure were unknown until Carl Ziegler finally discovered spatial arrangement-regulating catalysts in 1953 (This exploration of Bakht Yaraneh is explained in chapter 26). It turned out that in natural rubber, the arrangement of isoprene monomer units is “all-cis”; This arrangement could be mimicked by the new catalysts in synthetic rubber, whereas the previous catalysts caused a random arrangement of cis and trans units. It was only from this time that it became possible to produce synthetic rubber in such a way that it was almost impossible to distinguish between it and its natural counterpart. Today, the most important factor determining the use of natural or synthetic rubber in the manufacture of tires and other products is the price of oil, which is the raw material of synthetic rubber.
. Dr V. s. Calcott, who was doing research at DuPont’s Jackson Laboratory, noticed the research Newland’s father had done at the University of Notre Dame. Newland was a Catholic priest, president of the University of Notre Dame and a chemist. Publishing the results of his research showed that acetylene, a hydrocarbon with the formula H2C2, is added to itself under certain conditions once or twice, and creates vinylacetylene and divinylacetylene. Molecules with the formulas C6H6 and C4H4. According to Calcutt, these dimers and trimers might be very similar to the building block of natural rubber or isoprene that can be useful to make synthetic rubber. Some of the chemists under him engaged in this work at DuPont, but they did not get success. So he went to Wallace Carruthers who was a team leader in DuPont’s experimental station. The place where the most important research in the field of polymers was conducted.
Karuders became interested in the problem. He asked a chemist named Arnold Collins, who worked under his supervision, to purify a sample of the crude mixture obtained by the Newland method from acetylene. When Collins did this, he was able to separate a small amount of liquid that appeared to be neither vinylacetylene nor divinylacetylene, which Newland had not described.
But he didn’t throw it away and put it aside on his desk during the weekend. When he returned he found that the liquid had hardened, and after an examination, he witnessed its rubbery state to the extent that it would spring back when he drops it on his desk. You might say that this was no accident, but what Calcutt expected or even predicted. But when this rubbery solid was analyzed, it turned out not to be a polymeric form of the hydrocarbon acetylene, but to contain chlorine, which was completely unexpected. This chlorine was apparently from the hydrochloric acid (HCI) used in the Newland process. An acid to obtain acetylene dimers and trimers and added to vinyl acetylene. The product obtained from this addition was named chloroprene because of its similarity to isoprene. The only difference was in its monomer molecule. Then a chlorine atom is placed instead of a methyl group (a molecular unit consisting of one carbon atom attached to three hydrogen atoms, i.e. CH3). This spontaneous polymerization of chloroprene during a vacation on Mizkalins’s desk had created a rubber-like solid that the DuPont company called neoprene.
It turned out that this new synthetic rubber, unlike natural rubber, has a high resistance to oil, gasoline and ozone. These features made DuPont produce and market it in 1930 despite being more expensive compared to natural rubber. Neoprene is still in use and valuable. Its durability has been proven for heavy-duty boards and platforms such as industrial hoses, covering shoe soles, sealing around the glass, transmission belts of heavy mechanical forces and covering electrical cables. One of its new and interesting applications is the use of neoprene as an adhesive material for double-layered leather belts. With this material, two black and brown leather strips can be permanently glued together without sewing, and two-colour replaceable belts can be produced.
In 1924 c. s. Patrick decided to make a useful substance from large amounts of ethylene and chlorine gas, which were byproducts of industrial processes. They already knew that ethylene dichloride is obtained from the combination of these two substances; Patrick was experimenting with the reaction of various substances with ethylene dichloride, hoping to produce ethylene glycol, a marketable product. One of the substances he tried was sodium polysulfide. The reaction of this substance with ethylene dichloride did not produce the desired glycolic liquid, but a semi-solid and rubbery substance was obtained. Patrick immediately recognized the potential importance of this unexpected rubber object and began an extensive research project that soon led to a patent application and the establishment of a company to produce this new synthetic rubber.
The Thiokol Chemical Company, of which Patrick was president, launched Thiokol A in 1929. Its molecular structure was completely different from natural rubber, but at the same time, it was elastic. It had one advantage over natural rubber, and that was that it was resistant to oil materials like neoprene. But it didn’t take long before its big flaw was revealed: it smelled bad!
The Thiokol Company and others produced several polysulfide rubbers. In their use, their resistance to petroleum products and their good insulation properties, such as sealing around car windows and covering fuel tanks that are in the wings of aeroplanes, was used. Because Thiokol tires could be stabilized at low temperatures, they were used for a while as an adhesive and part of solid rocket fuels to launch satellites and spaceships into orbit. In 1982, Morton Salt Company bought Thiokol and formed Morton Thiokol; Both companies had produced specialty chemicals before the merger and continued to do so after the merger. The Morton Thiokol company, which was one of the main contractors in the construction of the unsuccessful Challenger space shuttle, suffered a lot of infamies. But the O-ring to which the spaceship explosion was attributed was not made from Thicol polysulfide synthetic rubber, but from Viton, a type of elastic polymer that is chemically more similar to Teflon.
The history behind tire’s evolution
Many of us have the habit of changing our worn tires regularly. But there is a strong probability that we don’t know anything about the history behind them. Today, many innovations have been made in the field of car tires. Radial tires, pneumatic tires, tire inflation indicators, etc. But what were the tires like in the early years of automobile invention? Let’s find out.
Durable tire construction
In the 19th century, horse-drawn carts and sleighs needed solid wheels to move over hard, rocky, or uneven terrain. For this work, wood or metal was used, which had high strength but had an equally dry and rough ride. For this reason, rubber was considered an alternative material to cover the wheels of the trucks. But this material had good resistance and adhesion only at normal temperatures and became very soft in hot weather and dry and brittle in a cold climate.
But in 1839, a man named Charles Goodyear (whose last name is familiar to the world) invented a process called vulcanization which made the rubber more resistant to sulfur and extreme heat. To the extent that under any pressure or bending, they could return to their original state. This invention contributed to the development of tires by a great margin
The invention of the pneumatic tire
In the mid-1880s, Europeans turned to bicycles and the manufacturing of their tires got more serious. Bicycle wheels in those years were made of wood which was covered by thick tires. But those tires were not comfortable enough and caused fatigue during long-term cycling. In addition, with the development of bicycles and the increase in their speed, people were looking for more comfort in this modern gizmo. While in 1945 the pneumatic tire was invented by a person named “Robert Thomson”, but in 1888 a man named “John Dunlop” (among other familiar names) due to the desire of his young son to have a more comfortable ride on a bicycle, the first practical and practical pneumatic tire invented and installed on a bicycle.
Early tires were permanently mounted on wheels and could not be removed. When pneumatic tires were invented, the problem became even bigger because pneumatic tires attached to the wheel were very difficult to repair. In 1890, a British man named “Edward Michelin” (again a familiar name in the tire industry) invented the first detachable pneumatic tire and installed it on a bicycle in 1891, and patented his invention.
In the early days of using pneumatic tires, these tires were made completely flat and without tread; But after tires were used in cars, due to the higher speed of cars compared to bicycles and use in different weather conditions, the need for better stability and traction of tires was felt. In 1904, the “Continental Tire of Germany” company invented treaded tires for the first time, and in 1908, the Goodyear company started producing these tires for moving on slippery roads.
Until the middle of the 20th century, tubular tires were used, and the first attempts to make tubeless tires were unsuccessful; But in 1946, the Goodrich company patented the invention of tubeless tires. It took until 1952 for this type of tire to reach the production stage, and finally, in 1954, the first production car in the United States was driven with tubeless tires.
Tires in the 21st century
Today, many innovations have occurred in the field of car tires. One of these innovations is the tire inflation indicator system, which is installed as a standard option in all new cars sold in the United States. This system shows the air pressure of each car tire to the driver and warns the driver if the air pressure is too low.