tiiSTORICAL NOTE

cement-could make a waterproof cloth. In 1823 Scottish chemist Rubber Stretches Over began producing his famous raincoats, misspelled as ";' that con• sisted of two layers of cloth coated with the rubber cement solution and then Two Anniversaries sandwiched together. Macintosh intro• duced coal-tar naphtha as a more effective Life got much easier for children at play the voyage. Instead, crude masses of solvent than turpentine or ether. a century ago this year. In 1888 in hardened raw rubber were shipped in Macintosh's partner, English inventor John Boyd , a successful Scottish cakes or balls. Once the shipments Thomas Hancock, continued to work veterinarian, invented the pneumatic reached Europe, the problem was how to with raw rubber, sure that "something to provide a more comfortable ride for his manipulate the rubber into a more desir• must eventually be done with so singular son's tricycle. Dunlop tested his tire in able form. Two Frenchmen, surgeon a substance:' Hancock patented the idea Great Britain in 1888 and in the United L.A.P. Herissant and chemist Pierre Jo• of applying strips of rubber directly to States in 18~. The smoother ride of air• seph Macquet, introduced the use of tur• cloth (in 1820) since his first attempts to filled instead of the previous solid pentine and pure ether as solvents for the coat fabrics with the turpentine/latex so• rubber ones helped bring about the cy• hardened latex. Using their technique, lution did not result in a satisfactory cling craze of the 1890s. they were able to make some of the first texture-and they smelled bad. Hancock After Dunlop's patent was issued, it rubber surgical instruments. also invented a machine called a "mastica• was discovered that the principle of the Others soon discovered that this solu• tor" that allowed the reprocessing of scrap pneumatic tire had already been patented tion of latex and turpentine-rubber rubber. in 1846, but Dunlop held enough acces• sory patents to keep his company going successfully, though he never did make a fortune from his invention. He sold the company along with his p\'ltent in 1896. Rubber will be celebrating another im• portant anniversary next year-150 years ago, in 1839, Charles Goodyear discov• ered the vulcanization process by spilling a mixture of rubber latex and sulfur on a hot stove. Vulcanization made rubber into the useful, durable material familiar to ev• eryone today. Rubber had been used centuries earlier in the New W>rld. When Christopher Co• lumbus returned from Haiti, he suppos• edly brought back rubber balls that he had seen the Indians bouncing against a tree. (This account was written more than 100 years after Columbus returned, so some historians doubt its authenticity.) Other Spanish explorers later learned how the South American Indians made water• proof shoes by smearing the milky white latex from rubber trees on their feet and allowing it to dry. They also made rubber bottles in much the same way... spreading the latex over a clay form and, when the latex had hardened, washing away the clay from the inside. In 1735, the explorer Charles Marie de La Condarnine-who had been commis• sioned by the Academy of Science of Paris to measure a degree of the meridian in South America-sent back to France hardened latex samples from Peru. The English chemist Joseph Priestley (better known as the discoverer of oxygen) no• ticed in 1770 that balls of the hardened la• tex could be used to rub out pencil marks ... from this we get the name "rub• ber:' Uquid latex couldn't be shipped back In 1839 Charles Goodyear discovered the vulcanization process by spilling a mixture of rubber across the ocean since it would dry out on latex and sulfur on a hot stove. Illustration courtesy of Goodyear Tire & Rubber Co.

MRS BULLETIN/JULY 1988 47 HISTORICAL NOTE

But natural rubber had a severe Trying to raise interest in his process problem-it softened and flowed when it (and to generate capital for further re• got too hot, and it hardened and cracked search), Goodyear sent samples of his when it grew too cold. Following Macin• vulcanized rubber to England. Thomas tosh's success and improving on Han• Hancock, Macintosh's business partner, cock's masticator machine, new obtained some of the samples and be• manufacturing techniques abounded• carne obsessed with learning the process but they reached the material limits of nat• that had so remarkably improved the ma• ural rubber until the substance itself could terial's utility. For nearly four years Han• somehow be improved. Natural rubber cock worked on his own to discover what could not be used in many ind~strial ap• Goodyear had done. plications, or even in the cold and heat of everyday seasonal fluctuations in the United States and Great Britain. The rub• [N]atural rubber had a severe ber became tacky, it h0:1d an unpleasant smell, and it degraded easily. problem-it softened and Then in 1839 the American Charles Goodyear discovered the vulcanization flowed when it got too hot, process. Goodyear was the son of an in• and it hardened and cracked ventor of farm implements. He and his fa• ther went into the hardware business when it grew too cold. together but went bankrupt In 1830, and Charles Goodyear was thrown in debtor's prison in 1834. While in prison, he began Meanwhile, Goodyear, in poor health to think about how valuable a material and dogged by creditors, finally got rubber could be if it didn't get hard in cold around to filing for his British patent in weather and sticky in warm weather. 1844-one year after Hancock h~d discov• Though he wasn't a chemist, nor did he ered a similar (and less effective) process have any clear idea of what might work, that didn't require lead. Thus began the he conducted his first experiments while first of many patent-infringement The QuaiHy still in prison; trying anything and every• battles-60 in all. Charles Goodyear was Plasma Source thing until he found a technique that to fight for the rest of his life. worked. He continued experimenting un• Once the Vl.llcanization process became • Unique symmetric plasma til his death in 1860. widely known, it became nearly impos• microwave coupler • UHV In 1836 he found a process .of treating sible to enforce patent restrictions be• compatible double-walled the rubber with nitric acid. The idea cause the technique itself was so simple. stainless plasma chamber looked promising and he secured a con• Goodyear spent most of his time fighting • Includes ASTEX S-,000 tract with the U.S. government to manu• legal battles, but he did not win his case microwave power supply with facture mailbags. The venture did not until 1852, with Daniel Webster acting as exceptional output quality prove successful. his lawyer. A year later he joined forces with Na• Goodyear traveled widely to promote (with regulation to 0.,% and thaniel Hayward, who had worked with a his vulcanization process, trying to gener• ripple less than 1%) for reli• rubber company and had proposed a a~e capital. French Emperor Napoleon III able processing • Ideal high process of using sulfur to "dry" rubber. awarded him the Legion of Honor, but current replacement in ion The process didn't work particularly well, that didn't get him any money. He fell beam applications, provides but Goodyear bought the right to use it deeper into debt, spent more time in a low energy ion stream, com• from Hayward anyway. Goodyear was debtor's prison (this time in France) and patible with any reactive gas working with a mixture of rubber, sulfur, finally died in 1860, owing more money for diamond-like coatings, lead, and other chemicals when he spilled than he ever had in his life-somewhere sputter and ion assisted it on a hot stove. The addition of heat did between $200,000 and $600,000. deposition, and etching the trick- "vulcanizing" the rubber, al• Unfortunately for Goodyear, the great• lowing the sulfur to act as a crosslinking est use of his vulcanized rubber-in auto• An extensive line agE;!nt for the polymer strands. The result• mobile tires-did not come about until 50 ing rubber di9n't melt as he expected ... in years after his death. Most of today's of quality microwave fact, it proved far more durable than any needs are filled by synthetic rubbers, plasma systems is rubber he had ever seen. other elastomers with similar (and some• The rubber industry had been centered times superior) material properties. But available. primarily on waterproofing clothes (in like John Boyd Dunlop, Goodyear's leg• Call for details. Great Britain) and on making rubber over• acy lives on with his name on our automo• shoes (in the United States), but with bile tires and his seminal work embodied Goodyear's new durable rubber, the in• in the corporation bearing his name. 617-876-5545 dustry could find mechanical applica• Applied Science and tions, such as tires and machinery. KEVIN]. ANDERSON Technology, Inc. 40 Allston Street Cambridge, MA 02139

MRS BULLETIN/JULY 1988