Materials | 7 MINUTE READ

Tracing the History of Polymeric Materials, Part 3

In this series we delve into a discerning look back into the history of our industry and how we all got here.   

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John Welsey Hyatt’s moldable material, the first true thermoplastic, was  based on the mercurial cellulose nitrate. An application such as billiard balls made from a material that was flammable and sometimes explosive was obviously problematic. The impact involved in the game produced a sound similar to a gun being fired, not a desirable quality when playing billiards in western saloons where everyone was armed. The addition of camphor as the preferred solvent for controlling the mechanical properties of the material did nothing to reduce the hazards associated with the material.

But Hyatt and his brother, Isaiah, recognized the potential of the new material to compete with rubber. In the 50 years between the time natural rubber was first dissolved in solvents and used to produce waterproof clothing and the time of celluloid’s invention, rubber had gone from a curiosity to a material on a fast track for the development of new markets.

In 1822 the world requirement for rubber was 31 tons, by 1870 it had grown to 9100 tons. While this was minuscule in comparison to what would happen as the automotive industry began to adopt rubber for tires at the turn of the century, this initial level of growth gave rise to an organization of rubber producers that succeeded in colluding with each other to establish very high prices for the material and products made from it.

One of these products was dental plate blanks for making dentures. The Hyatt brothers tried to interest the rubber companies in using celluloid. While in today’s world we think of rubber and plastics as closely related, in the 1870’s the rubber industry saw the new thermoplastic as a significant threat to its dominance in the market. To introduce celluloid to the dental practice, the Hyatts had to compete rather than cooperate with the rubber companies. To make products from celluloid, John Wesley Hyatt created several different processing methods for forming the material, including compression molding and ram extrusion.

But probably the most important processing method invented by Hyatt was the device specifically designed for making dental plates. This machine consisted of a cylinder that tapered at one end to a nozzle. This cylinder was surrounded by a jacket filled with oil and heated with gas. The opposite end of the cylinder contained a piston and a screw that could be turned with a lever to force molten material through the heated nozzle. In other words, an injection molding machine.

Probably the most important processing method invented by Hyatt was the device specifically designed for making dental plates.

The competition between the rubber cartel and the nascent thermoplastic industry centered on dental hardware. Both materials possessed drawbacks that would doom them to failure in our modern era. Rubber dentures tasted of the sulfur used to cure the material; celluloid tasted of the camphor used to control its viscosity and mechanical properties. Celluloid promised to break the rubber oligopoly and bring prices down dramatically.

Celluloid, the first true thermoplastic, had the drawback of extreme flammability. It was used for the  first film stock, which caused quite a number of movie-theater fires when film jammed in hot projectors.
 

But celluloid was susceptible to warping at the elevated temperatures associated with hot drinks, an obvious performance problem that the rubber industry was only too happy to exploit. And whenever the rubber market appeared to be threatened by the new material, the rubber cartel circulated rumors about health concerns with celluloid, shades of today’s scare tactics regarding the public perception of plastic materials. But unlike today’s negative publicity, these attacks came from within the polymer industry.

Despite the challenges facing celluloid, some New York investors showed an interest in backing its development on the condition that Hyatt move his operation from Albany down to the New York City area. The new plant was established in Newark in 1872. Three years later the well-known volatility of the material was on full display when the factory caught fire and burned to the ground in a matter of a few hours.

Despite this setback and the publicity fallout ensured by the rubber industry, celluloid found a market as a substitute for the materials traditionally used in jewelry such as bone, marble, tortoiseshell, horn, and ivory, and in personal-care products such as combs and backings for brushes. A very successful application was found in shirt collars and cuffs. The moldability of the material allowed it to be pressed against a fabric to replicate the pattern of the cloth onto the surface of the white polymer. It could then be shaped into less expensive substitutes for actual linen collars and cuffs. This, of course, led to apocryphal and perhaps true stories circulated by the rubber industry about people getting too close to a fire or touching a cuff with a lit cigarette or cigar with disastrous consequences.

Rayon, a fabric based on nitrocellulose formed into thin filaments, was another creation of the late 19th century that highlighted the hazards of this early polymer when used in clothing articles. The original rayon was so flammable that it garnered the wryly humorous and not so politically correct name “mother-in-law silk.” The name rayon persists today and the material is still based on cellulose, however it is processed in a completely different manner and is no longer flammable.

The conflict between the utility and the volatility of chemistries based on cellulose nitrate took other forms. One of the early uses for collodion, the form of cellulose nitrate dissolved in ether and alcohol, was as a film for protecting glass photographic plates. Alexander Parkes had conceived of the idea of making a self-supporting structure that could produce photographs without the need for the glass plate. Through a series of developments over the next four decades, a chemistry for a self-supporting film with the needed mechanical properties based on collodion was developed by George Eastman and his colleagues using advances in chemistry that had originated within Hyatt’s Celluloid Company.

Of course, these histories are never as simple as they first appear. Eastman applied for his patent on flexible film in March of 1889 and it was awarded a month later. However, in 1887, an Episcopal priest named Hannibal Goodwin, a man with no scientific training or education in chemistry, had approached the Celluloid Company, a neighbor of his church, for help in replacing glass slides for his regular lectures on religious subjects at his church in Newark, New Jersey. His efforts produced a workable film made from celluloid and he filed a patent for it two years before Eastman filed his. However, for reasons lost to history, the patent was not issued until 1898.

This brought about the inevitable lawsuit. Goodwin sued Eastman for a share of the profits that Eastman’s company, Eastman Kodak, had been making on the sale of their film for almost a decade. While Eastman came from humble beginnings, by this time he was the one with the economic resources, and he kept the suit tied up in court until 1914. In the interim, Goodwin had sold the company he had founded, Goodwin Film and Camera Company, and had died in 1900. But the suit was decided in Goodwin’s favor, to the benefit of his heirs and the company to whom he had sold the patent rights.

The early years of cinema are full of incidents in which bright, hot projector lights ignited film that had jammed in the projector. 

The celluloid film was adopted by Thomas Edison and others as the material of choice for moving pictures as the 19th century drew to a close. The flammability of cellulose nitrate was once again evident. The early years of cinema are full of incidents in which bright, hot projector lights ignited film that had jammed in the projector. Early theaters frequently went up in flames, killing many either in the fires or the associated panic. The 1919 comment from Supreme Court Justice Oliver Wendell Holmes, Jr. about shouting “Fire!” in a crowded theater was likely related to the fact that these occurrences were very much on the minds of people at that time.

Cellulose-based materials represented an important first step in the history of polymers, and we will come back to them in a later installment. While they represented an ingenious manipulation of a naturally occurring chemistry, they still did not represent a true synthetic material. In our next article, we will discuss that development.

ABOUT THE AUTHOR: Mike Sepe is an independent, global materials and processing consultant whose company, Michael P. Sepe, LLC, is based in Sedona, Ariz. He has more than 40 years of experience in the plastics industry and assists clients with material selection, designing for manufacturability, process optimization, troubleshooting, and failure analysis. Contact: (928) 203-0408 • mike@thematerialanalyst.com.

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