Around the 1740’s, English clergyman, political theorist, and physical scientist Joseph Priestly observed how well samples of Hevea sap collected by natives in the New World rubbed pencil marks off paper. The pencil mark “rubber” had been being used by the Natives to make various products: shoes, coats, balls for games, and bottles, hundreds of years before Priestley.
About 80 years after Priestley, Scottish chemist Charles Macintosh figured out how to dissolve rubber in coal tar. Pretreating the sap made it less sticky and more usable for cloaks. To this day, “Macintosh” is a genericized name for a raincoat in Great Britain.
Thomas Hancock was an English inventor and contemporary of Macintosh. Hancock worked on creating elastic thread for clothing and footwear by carving strips off lumps of imported rubber. The application of the strips generated unusable lengths which were discarded for scrap. Hancock built a hollow wooden cylinder with teeth with the intention of shredding the scraps. Rather than shred the scraps it welded them together. Hancock is credited with discovering the effect of mastication in rubber production. Although Macintosh’s solvent treatment and Hancock’s chewing treatment helped with the rubber’s stickiness and incoherency, the material still had some drawbacks: it softened with heat, hardened with cold, was tacky, smelled, and perishable.
Enter the Philadelphian prisoner, implement manufacturing pioneer, oldest of 6, born of Nutmeggers in good standing, and self-taught chemist, Charles Goodyear.
While in prison for debt to his hardware store’s suppliers, he discovered that mashing magnesium into un-processed rubber reduced the material’s stickiness. This discovery inspired Charles and his Family to begin making shoes and life preservers and other products out of their home in Philadelphia. Early decay of some of his first products thrust him back into poverty however, and he sold his home and the furniture inside of it, and moved away from his wife and children to an attic in New York where he continued to experiment with “India Rubber”. As if his home, wife, and children were not enough, Charles almost gave his life to his research with rubber from inhaling nitric acid + rubber exhaust in Greenwich Village. About the time his research was starting to yield usable marketable products, the Great Depression hit, scared off his investor, and left him again penniless. For the following decade he bummed around Massachusetts firms including Roxbury Rubber Company and Eagle India Rubber Company. At the Roxbury, with the help of a Mr. Chaffee, Goodyear started using mechanical mixing of the natural rubber and additives. At Eagle India Rubber Company, he discovered that mixing rubber and sulfur over a hot stove resulted in a new material that was more desirable for manufacturing products. Goodyear patented the process along with a colleague from the Eagle India Rubber Company, the American inventor and businessman Nathaniel Hayward. Hancock had established a patent in Great Britain for processing unprocessed rubber, but Charles Goodyear gave his treatment of the raw material the super-cool name of “Vulcanization” – which he named after the Roman god of Fire; Vulcan.
Charles Goodyear died at the age of 59 after arriving at a Fifth Avenue New York hotel too late to see his daughter, who had just passed. 40 years later American Frank Seiberling founded the Goodyear Tire and Rubber Company.
In addition to Natural Rubber, there is Synthetic, or man made rubber. Rather than come from trees, man made rubber is manufactured in a laboratory. Synthetic rubbers such as isoprene, have become materials in and of themselves. It is like scientists were trying to imitate natural rubber, and ended up making a new material that has it’s own attributes that make it good or bad for different applications, wholly apart from vulcanized natural rubber.
The noun “steel” is an English translation of early German stahlija, and stahljah is literally translated ‘standing firm’. Steel is an alloy of iron that has less than 2.14% carbon by weight. As opposed to manmade steel, that’s used in building weapons, appliances, and tools, the 4 allotropes of pure iron are soft and malleable. Allotropes of an element are arrangements of an element’s atoms in different ways. An example of two allotropes of pure carbon are graphite and diamonds. Where iron and carbon are naturally occurring elements, steel must be made.
For thousands of years man has used bloomeries to refine and burn away the carbon in iron ore until he had a steely tool. Bloomeries were the precursors of blast furnaces which were the precursors of modern mass produced steel making. Essentially a bloomery must be super hot and it is a chimney with a hole in the bottom so that air can be forced into the fire so that the fire burns super hot.
Wrought Iron is an alloy of iron with too much slag left in the bloom.
Obviously then we see how much energy and natural resources it takes to make the 135lb conglomeration of steel and rubber: the modern truck tire. So much is required to make each new truck tire, that from their inception, they are intended to be retreaded. When a truck tire is sent to the landfill before it’s time, kilojoules go with it. If you’re running retreads, good job. If not, please rethink this, challenge a local retreader to address the reasons you have for not doing so. Thanks for reading!