Cellulose celluloid

Regenerated cellulose Triacetyl cellulose Nitro-cellulose Celluloid... 

During the nineteenth century much interesting work was performed on polymeric materials beginning with the vulcanisation of rubber in 1839 and also including the development of nitrated cellulose (celluloid) in 1868. It was not until after the turn of the century that the first commercially successful fully synthetic plastic was produced. 

The earliest thermoplastics were the cellulosics. Celluloid or cellulose nitrate, followed by cellulose acetate, cellulose acetate butyrate and, more recently, cellulose propionate, have all found their special uses, but cellulose nitrate is used very little currently because of flammability risks. 

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... 

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

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. 

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

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. 

ASTM American Society for Testing CN cellulose nitrate (celluloid)... 

The first of the thermoplastic synthetic polymers to be developed was celluloid, made by combining nitrated cellulose (pure cotton subjected to nitric acid) and camphor (C10H16O), a plasticizer. The motivation was a search for a replacement for the ivory used in making billiard balls. It became a commercial product circa 1865, and is still used for making ping-pong balls. 

Cellulose nitrate (Celluloid) 1850 Moulding material, paints, glues, coatings, photographic films, varnishes Camphor, phthalate esters High flammability and degradability, with production of nitrogen dioxide... 

The first partially synthetic polymer dates back to 1869, when cellulose (wood pulp) was nitrated (nitrocellulose). The cellulose became ptocessible, and with the further addition of camphor (which acted as a plasticizer), it became a clear, tough, moldable product with the trade name Celluloid. It was widely used at the end of the 19th century in the form of combs, brushes, photographic film, and shirt collars. 

Uses Plasticizer for cellulose esters and ethers manufacture of plastics, cymene, incense, celluloid in lacquers, explosives, and embalming fluids pyrotechnics moth repellent preservative in pharmaceuticals and cosmetics odorant/flavorant in household, pharmaceutical, and industrial products tooth powders. 

Uses Solvent for celluloid, cellulose acetate, fats, oils, waxes, nitrocellulose and resins wood preservatives rayon and artificial leather imitation gold leaf extraction of resins and waxes in antifreeze mixtures and hydraulic fluids laboratory reagent preservative for animal tissue dyeing mixtures stripping agent for textiles. 

The most widely used inorganic ester of cellulose is cellulose nitrate (CN), also called nitrocellulose or gun cotton. Celluloid is produced from a mixture of CN and camphor. It was first made in 1833 when cellulose-containing linen, paper, or sawdust was reacted with concentrated nitric acid. It was the first synthetic cellulose product that was recognized. Initially, CN was used as a military explosive and improvements allowed the manufacture of smokeless powder. A representation of CN is given in structure 9.7. 

In 1905, British inventor John C. Wood was working with cellulose and developed a method to adhere glass panes using celluloid as the adhesive. Wood s version of shatter-resistant glass was produced under the band name Triplex since it consisted of outer layers of glass with an inner layer of celluloid polymer. 

Till this time, polymer science was largely empirical, instinctive, and intuitive. Several polymers were commercially available prior to World War I celluloid, shellac, Galalith (casein), Bakelite, and cellulose acetate plastics hevea rubber, cotton, wool, and silk rayon fibers Glyptal polyester coatings bitumen or asphalt, and coumarone-indene and petroleum resins. However, as evidenced by the chronological data shown in Table 1.1, there was little... 

Esters and ethers of cellulose, and especially nitrocellulose, are most widely used in the form of a colloidal solution. This technique is applied in the manufacture of smokeless powder, nitrocellulose varnishes, film and celluloid. 

If the linters are to be used for the manufacture of particularly pure, white collodion cotton intended for production of varnishes or celluloid, it is necessary to remove any iron compounds from the cellulose. This can be carried out by washing the cotton with an oxalic add solution, followed by a water rinse. 

Bleaching. Crude wood cellulose is bleached by means of calcium or sodium hypochlorite in large tanks, bleachers , equipped with stirrers. Bleaching cellulose is of great importance for nitrocellulose manufacture, particularly in the case of nitrocellulose intended for the production of smokeless powder. It is essential that the powder should be pale in colour, as a change in the colour of the powder often indicates decomposition. Similarly, cellulose destined for manufacturing collodion cotton, for varnishes, celluloid and film, should be carefully stripped of colour so that the final products are colourless. 

Celluloid and cellophane are both derived from cellulose. The celluloid, however, has nitrate groups, whereas each hydroxyl group appears in cellulose. Cellophane has the same chemical composition of cellulose, but it has been transformed to a film by both chemical and mechanical processing. 

HYATT, JOHN WESLEY (1837-1920). Hyatt is generally credited as being the father of the plastics industry. In 1869. he and his brother patented a mixture of cellulose nitrate and camphor which could be molded and hardened. Its lirsl commercial use was lor billiard balls. The TM Celluloid" was the first ever applied to a synthetic plastic ptoduci, it hammahtlity hazard limits its use. 

---