Nitrate plastic

Some work was also done by Consaga et al. on cyclodextrin nitrates with a view to replacing NC [5]. The composites of this invention are mixtures of (i) a cyclodextrin nitrate or a mixture of cyclodextrin nitrates and (ii) an energetic organic nitrate plasticizer. These composites are useful as replacements for nitrocellulose (NC) because they are more thermally stable and less sensitive to impact and yet have comparable or greater energy content than NC. However, cyclodextrin nitrates are dry powders that are sensitive to electrostatic discharge (ESD). 

Although Lhe first cellulose plastic (cellulose nitrate plastic-based on an inorganic ester of cellulose) was developed in 1865. the first organic cellulose ester plastic was not offered commercially until 1927. In that year, cellulose acetate plastic became available as sheets, rods, and tubes. Two years later, in 1929. it was offered in the form of granules for molding. It was the first thermoplastic sufficiently stable to be melted without excessive decomposition, and it was the first thermoplastic to be injection molded. Cellulose acetate butyrate plastic became a commercial product in 1938 and cellulose propionate plastic followed in 1945. The latter material was withdrawn after a short time because of manufacturing difficulties, but it reappeared and became firmly established in 1955. 

Some older foreign proplnts resembled, in their compns, Celluloid(see under Camphor). Use of Celluloid as bottom closing screw disc for time fuzes is described in Ref 3 and a smoke -producing device in Ref 7. Uses of Celluloid in some Brit ammo are discussed in conf Ref 10 The following two Celluloid Type compns are used in US for military purposes (Ref 12) a)Composition A Cellulose Nitrate Plastic shall be manufd from NC(ca 11% N) ca 3parts, camphor ca lpart, urea 0.75 i 0.05% of dry wt of NC and solvent in amt sufficient for... 

The industrial change and expansion of the nineteenth century had many strands and among them attention was given to man-made replacements for resinous compositions and horn. Alexander Parkes, a prolific inventor and manufacturer, was involved closely with the search for commercial materials he showed articles of Parkesine (a cellulosic) at the Universal Exhibition in London in 1862. Further investigations and development led eventually in Britain, Germany, the USA, and elsewhere to the industry based on a cellulose nitrate plasticized with camphor and (somewhat later) to cellulose acetate and to other cellulose plastics (cellulose acetate butyrate, ethyl cellulose, etc.). 

An early important commercial use for the cellulosics was to replace ivory in making billiard balls, and while today this certainly would win approval by green enthusiasts it is not far-fetched to imagine at the time some habitues of the tables grumbling that the plastic balls just were not the same . When perfected eventually in a commercial sense cellulose nitrate plastics were more consistent in appearance and quality than tusks, and duly replaced them too for uses such as piano keys and handles for table cutlery in products like these they were an economical and practical substitute but in stiff collars and cuffs— another important early application (eventually, millions were made) to help keep clerks, nannies, and others looking smart throughout the working... 

Table XI, page 144, gives indications of temperatures of processing for a number of materials. With cellulose nitrate plastics in particular there was a risk of explosion if over-heating took place, so besides all normal safety precautions for press-work the operating temperature of presses was subject to strict control.

The cellulose nitrate plastics were adaptable, easy to work, and quite durable, but had the disadvantages of being plasticized with camphor and flammability (they burnt, in fact, quite violently). At one time the smell of camphor was thought pleasant (even therapeutic) but instances have been cited of harm to children attributed to inhaling this vapour. So, while the acetates were not quite so attractive in terms of ease of fabrication it was inevitable eventually that the so-called safety plastic would supersede its forerunner. Among other uses it was stitched into motor car tonneau covers as flexible glazing, and thicker transparent sheet was cut and formed into cockpit canopies for aircraft [though by that time the material preferred for this purpose was poly(methyl methacrylate)]. Later on, in their turn, sheets made from cellulose acetate butyrate and propionate took over some of the uses of earlier commercial materials. 

Cellulose nitrate (plasticized with Yellow Camphor Burns very fast, often with explosion... 

Celluloid Dynamit Nobel Cellulose nitrate plasticized with camphor... 

Hyatt, John Wesley (1837-1920) During the 1860s John Wesley Hyatt developed cellulose nitrate plastic and successfully produced and marketed billiard balls as a less expensive alternative to ivory billiard balls. See cellulose nitrate plastic plastic history. 

Formula 149 is according to MFL-C-15567 (1950), Cellulose Nitrate Plastic (Celluloid or Pyroxylin Type), for use in ammunition also called Composition B, Up to 5 % of residual solvent is permitted. Also covered in MIL-C-15567 is a Composition A for sheets and other shapes of approximately 3 parts to 1 part NC to camphor with 3/4% urea added. 

Celluloid Cellulose nitrate, plasticized with camphor Dynamit Nobel, Germany... 

After the failure of the Parkesine Company, Parkes and Daniel Spill formed the Xylonite Company which produced cellulose nitrate plastics under the trade names of Xylonite and Ivorude. Camphor, which Parkes claims to have used as a plasticizer or solvent was mentioned in his patent in 1855. Daniel Spill patented compositions containing cellulose nitrate and camphor in 1869. 

Scheme 12 Preparations of difluoramino-substituted nitrate plasticizers...

Scheme 13 Preparation of a gefn-bis(difluoramino)-substituted nitrate plasticizer [108]...

Then came several semisynthetic polymers, which were natural polymers modified in some way. One of the first to attain commercial importance was cellulose nitrate plasticized with camphor, popular around 1885 for stiff collars and cuffs as celluloid, later most notably used in Thomas Edison s motion picture film (11). Cellulose nitrates were also sold as lacquers, used to coat wooden staircases, and so on. The problem was the terrible fire hazard existing with the nitrates, which were later replaced by the acetates. 

As mentioned previously, celluloid is cellulose nitrate plasticized with camphor. At the present time, the material is produced mainly in sheet form. In a typical process alcohol-wet cellulose nitrate is kneaded at about 40°C with camphor (about 30%) the ethanol-camphor mixture constitutes a powerful solvent for the polymer and a gelatinous mass is obtained. Colourants, if any, are added at this stage. The dough is then heated at about 80°C on rollers until the alcohol content is reduced to about 15%. The calendered sheets are laid up in a press and consolidated into a block. The block is then sliced into sheets of thickness 0.005-1 in various multi-colour effects may be obtained by plying sliced sheets of different colours and then re-slicing on the bias. The sheets are then allowed to season for several days at about 50°C so that the volatile content is reduced to about 2%. 

The natural source of high-purity camphor is a tree, Cinnamomum camphorae, native to south-east Asia but cultivated more widely. In the early twentieth century, camphor was one of the first organic materials to be synthesized industrially from inorganic starting materials. Camphor sublimes at room temperature (see below). Camphor was one of the earliest and best plasticizers (at 25 0%) for cellulose nitrate plastics (Miles, 1955) though it has largely been replaced by liquid plasticizers. 

Plastics can degrade in more spectacular ways, too. An early widespread use for cellulose nitrate plastics was for film stock, which becomes potentially explosive as its chemistry alters through time, as well as becoming brittle. Museum curators who have plastic objects in their collections tell horror... 

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