Celluloid

Nitrocellulose was invented in 1845 by Schonbein, a professor at the University of Basel. It quickly drew attention from the academic circle first, as a material for a fiber with silky feel, but ultimately as a raw material for the production of celluloid, lacquer, smokeless powder and dynamite. 

On July 14, 1847, two years after the invention of nitrocellulose,an accidental fire caused by the spontaneous ignition of nitrocellulose occurred in a factory producing it in Great Britain. Twenty lives were reportedly lost n. In 1948, a fire took place in a nitrocellulose warehouse in France. For a period of sixteen years after this accident, production of nitrocellulose was prohibited in Great Britain and France. In the U.S.A. and the U.S.S.R. it was also temporarily prohibited. 

Celluloid, an artificial plastic made from nitrocellulose and camphor, was invented by Parkes from Britain and the Hiatt brothers, printers in the U.S.A. (USP 88634 (1869)). The inventions of photographic films by Eastman Co. in 1885 and of movies by Edison in 1895 markedly expanded the demands for celluloid, bringing about a major increase in large scale accidents, the effects of which were magnified by involving many people in enclosed spaces. 

According to a survey by Kogaku Komamiya 2), a film fire during the showing of a movie in the U.S.S.R. in 1929 killed 144 people. In Japan there were 40 fires that happened during the showing of movies in 1930, and 70 in 1951, for which the loss of 124 lives was recorded. 

A fire of celluloid film that became a news item in Japan in recent years occurred in the National Modem Museum J). The fire, at about 14 47 on September 3, 1984, was caused by the spontaneous ignition of nitrocellulose films in the film storeroom on the fifth floor of the museum. The fire damaged a considerable number of the 3,000 reels of foreign movies that were stored there. On December 16, 1932, a disastrous fire caused by the burning of celluloid toys on a counter of Shirakiya Department Store resulted in the death of 14 saleswomen who could not escape and the injury of 21 other people. 

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Ordinary commercial camphor is (-i-)-cam phor, from the wood of the camphor tree. Cinnamonum camphora. Camphor is of great technical importance, being used in the manufacture of celluloid and explosives, and for medical purposes, /t is manufactured from pinene through bornyl chloride to camphene, which is either directly oxidized to camphor or is hydrated to isoborneol, which is then oxidized to camphor. A large number of camphor derivatives have been prepared, including halogen, nitro and hydroxy derivatives and sulphonic acids. 

Dehydrated (e.g. AICI3) to cyclohexene. Used in the manufacture of celluloid, esters (plasticizers), detergents and printing inks. 

Colourless liquid with a strong peppermintlike odour b.p. 155" C. Manufactured by passing cyclohexanol vapour over a heated copper catalyst. Volatile in steam. Oxidized to adipic acid. Used in the manufacture of caprolactam. Nylon, adipic acid, nitrocellulose lacquers, celluloid, artificial leather and printing inks. 

The first satisfactory photographic film was produced in 1888 when gelatin-dispersed microcrystals of silver haUde were coated on celluloid sheets (23). Within a year George Eastman prepared and marketed toU films on a base produced by dissolving nitrocellulose with camphor and amyl acetate in methanol (qv). 

The principal chemical iadustry based on wood is pulp and paper. In 1995, 114.5 x 10 metric tons of wood were converted iato - 60 x 10 metric tons of fiber products ranging from newsptint to pure cellulose ia the United States (1,76). Pure cellulose is the raw material for a number of products, eg, rayon, cellulose acetate film base, cellulose nitrate explosives, cellophane, celluloid, carboxymethylceUulose, and chemically modified ceUulosic material. 

The rubber polyisoprene is a natural polymer. So, too, are cellulose and lignin, the main components of wood and straw, and so are proteins like wool or silk. We use cellulose in vast quantities as paper and (by treating it with nitric acid) we make celluloid and cellophane out of it. But the vast surplus of lignin left from wood processing, or available in straw, cannot be processed to give a useful polymer. If it could, it... 

By 1900 the only plastics materials available were shellac, gutta percha, ebonite and celluloid (and the bitumens and amber if they are considered as plastics). Early experiments leading to other materials had, however, been carried out. The... 

Whereas celluloid was the first plastics material obtained by chemical modification of a polymer to be exploited, the phenolics were the first commercially successful fully synthetic resins. It is interesting to note that in 1963, by a merger of two subsidiary companies of the Union Carbide and the Distillers organisations, there was formed the Bakelite Xylonite Company, an intriguing marriage of two of the earliest names in the plastics industry. 

I. KAUFMAN, M., The First Century of Plastics—Celluloid and its Sequel, The Plastics Institute, London (1963)... 

The first commercially available acetal resin was marketed by Du Pont in 1959 under the trade name Delrin after the equivalent of ten million pounds had been spent in research or polymers of formaldehyde. The Du Pont monopoly was unusually short lived as Celcon, as acetal copolymer produced by the Celanese Corporation, became available in small quantities in 1960. This material became commercially available in 1962 and later in the same year Farbwerke Hoechst combined with Celanese to produce similar products in Germany (Hostaform). In 1963 Celanese also combined with the Dainippon Celluloid Company of Osaka, Japan and Imperial Chemical Industries to produce acetal copolymers in Japan and Britain respectively under the trade names Duracon and Alkon (later changed to Kematal). In the early 1970s Ultraform GmbH (a joint venture of BASF and Degussa) introduced a copolymer under the name Ultraform and the Japanese company Asahi Chemical a homopolymer under the name Tenal. 

Although originally a trade name the term celluloid has come into general use to describe camphor-plasticised cellulose nitrate compositions. 

The celluloid dough is then filtered by forcing through a pad of calico and brass gauze backed by a heavy brass plate at a press of about 1.5 tons per square inch. Any undesirable foreign matter is thus separated from the dough. 

It is also possible to extrude alcohol-containing celluloid compositions through either ram or screw extruders under carefully controlled conditions. The process is now believed to be universally obsolete. 

Nitration of cellulose followed by plasticisation of the product with camphor has the effect of reducing the orderly close packing of the cellulose molecules. Hence whereas cellulose is insoluble in solvents, except in certain cases where there is chemical reaction, celluloid is soluble in solvents such as acetone and amyl acetate. In addition the camphor present may be dissolved out by chloroform and similar solvents which do not dissolve the cellulose nitrate. 

The solvation by plasticiser also gives celluloid thermoplastic properties owing to the reduction in interchain forces. On the other hand since the cellulose molecule is somewhat rigid the product itself is stiff and does not show rubbery properties at room temperature, cf. plasticised PVC. 

The chemical resistance of celluloid is not particularly good. It is affected by acids and alkalis, discolours on exposure to sunlight and tends to harden on aging. More seriously it is extremely inflammable, this being by far the greatest limitation of the material. 

Typical physical properties of celluloid are compared with other cellulose plastics in Table 22.2. 

The high inflammability and relatively poor chemical properties of celluloid severely restrict its use in industrial applications. Consequently, the material is used because of the following desirable characteristics. 

The annual production of celluloid is now negligible compared with the total world production of plastics. 

Today the principal outlets are knife handles, table-tennis balls and spectacle frames. The continued use in knife handles is due to the pleasant appearance and the ability of the material to after-shrink around the extension of the blade. Table-tennis balls continue to be made from celluloid since it has been difficult to match the bounce and handle of the celluloid ball, the type originally used, with balls fabricated from newer polymers. Even here celluloid is now meeting the challenge of synthetic polymers. Spectacle frames are still of interest because of the attractive colour. There are, however, restrictions to their use for this application in certain countries and cellulose acetate is often preferred. 

With the exception of some of the natural rubber derivatives these materials were available during the first deeade of this eentury and, together with celluloid, aetually completed the range of plastics materials then in eommercial use. In spite of being ousted from important markets they have continued to find use in specialised applications, details of which will be given in subsequent sections of this chapter. The historical significance of these materials was dealt with in the first chapter of this book. 

Polymers have come a long way from parkesine, celluloid and bakelite they have become functional as well as structural materials. Indeed, they have become both at the same time one novel use for polymers depends upon precision micro-embossing of polymers, with precise pressure and temperature control, for replicating electronic chips containing microchannels for capillary electrophoresis and for microfluidics devices or micro-optical components. 

Bone meal, bone black Brewing grains, spent Carbon Celluloid... 

SEIW 987 Celluloid fire dangers. Warning to workers. (Leaflet)... 

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