Cellulose nitrate plastic

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 The latter material was withdrawn after a short time because of manufacturing difficulties, but it reappeared and became firmly established in 1955. 

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.). 

Preparation of semi-synthetic polymers. Cellulose plastics, particularly cellulose nitrate and acetates, were the most commercially-important semi-synthetics, and have been used to prepare photographic films, textile fibres and lacquers. 

Reaction Scheme 1 shows that during preparation of cellulose plastics, the hydroxyl groups on each cellulose monomer ring are replaced by other substituent groups. To prepare cellulose nitrate, pre-dried cotton linters are treated with concentrated nitric and sulfuric acids. Water tends to slow the reaction, so its presence is limited. Sulfuric acid catalyses the reaction, so it can occur without heating and under ambient conditions. The product is washed with water to remove the residual acids if residues of sulfuric acid are allowed to remain, an explosive reaction can occur. Remaining water in the cellulose nitrate is displaced by alcohol. 

OTHER COMMENTS used in the manufacture of furfuralphenol plastics used in the manufacture of varnishes solvent for cellulose acetate, nitrate eotton, and gums used in the synthesis of furan derivatives and in the preparation of pyromueic acid also used as an insecticide, fungicide and germicide reagent in analytical chemistry. 

Cellulose is nitrated by mixtures of nitric and sulfuric acids. The type of acid mixture used depends on the intended products. For the preparation of plastic grade materials, 25% nitric acid is combined with 55% sulfuric acid and 20% water. The dried cellulose is soaked for 20-60 minutes at 30-40 C. There is little change in appearance as the structure of the cellulose is maintained. The bulk of the acid is then removed, usually by spinning in a centrifuge, and the remaining acid washed out with copious amounts of water. The product is often bleached with sodium hypochlorite and washed. 

Isoamyl butyrate Phenoxyethanol plasticizer, cellulose acetate lacquers Dimethyl phthalate plasticizer, cellulose acetate, nitrate 2-Nitro-1,1 -biphenyl plasticizer, cellulose compounds N,N-Butyl benzene sulfonamide plasticizer, cellulose ester N-(2-Hydroxypropyl) benzenesulfonamide plasticizer, cellulose ester plastics Dihexyl phthalate... 

These plastics (cellulose acetate, cellulose acetate butyrate (CAB), cellulose nitrate, cellulose propionate, and ethyl cellulose) are ordinarily solvent cemented, but for bonding to non-solvent-cementable materials, conventional adhesives must be used. Adhesives commonly used are polyurethanes, epoxies, and cyanoacrylates. Cellulosic plastics may contain plasticizers that are not compatible with the adhesive selected. The extent of plasticizer migration should be determined before an adhesive is selected. Recommendations for conventional adhesives for specific cellulosic types are as follows ... 

Dope dop [D doop sauce, fr. dopen to dip akin to OE dyppan to dip] (1807) n. (1) A solution of a cellulosic plastic, historically cellulose nitrate, used for treating fabrics. (2) Cellulose ester lacquer for adhesive or coating purposes. 

Cellulose nitrate (CN) or nitrocellulose is a nitric acid ester of cellulose manufactured by the action of a mixture of sulfuric acid and nitric acid on cellulose, such as purified cotton linters. The major use of plastics-grade cellulose nitrate is in the coating field. Despite its disadvantages of flammability, instability, and poor weathering properties, cellulose nitrate is one of the cheapest and most highly impact-resistant plastic. It still has many uses because of these properties, including fountain pens, tool and brush handles, eyeglass frames, and some motion picture film. It accounts for only a small fraction of the volume of cellulose plastics. Cellulose nitrate materials are sometimes simply called nitrates. 

Aryl Phosphates. Aryl phosphates were introduced into commercial use early in the twentieth century for flammable plastics such as cellulose nitrate and later for cellulose acetate. CeUulosics are a significant area of use but are exceeded now by plastici2ed vinyls (93—95). Principal appHcations are in wire and cable insulation, coimectors, automotive interiors, vinyl moisture barriers, plastic greenhouses (Japan), furniture upholstery, conveyer belts (especially in mining), and vinyl foams. 

During World War I, cellulose acetate replaced the highly flammable cellulose nitrate coating on airplane wings and the fuselage fabrics. After World War I, it found extensive use in photographic and x-ray films, spun fibers, and mol ding plastics. 

Uses. Cellulose nitrates with differing nitrogen contents have various appHcations (Table 3). The largest iadustrial use of CN is protective and decorative lacquer coatings. CN is soluble ia a variety of organic solvents and yields clear, tough films. CN is also compatible with many plasticizers and resias. 

Citric acid esters are used as plasticizers ia plastics such as poly(viayl chloride), poly(vinhdene chloride), poly(viQyl acetate), poly(viQyl butyral), polypropylene, chlorinated rubber, ethylceUulose, and cellulose nitrate. Most citrate esters are nontoxic and are acceptable by the FDA for use in food-contact packaging and for flavor in certain foods. As a plasticizer, citrate esters provide good heat and light stabiUty and excellent flexibiUty at low temperatures. Triethyl citrate, tri- -butyl citrate, isopropyl citrate, and stearyl citrate are considered GRAS for use as food ingredients (224—228). 

One principal use of cyclohexanol has been in the manufacture of esters for use as plasticizers (qv), ie, cyclohexyl and dicyclohexyl phthalates. In the finishes industry, cyclohexanol is used as a solvent for lacquers, shellacs, and varnishes. Its low volatiUty helps to improve secondary flow and to prevent blushing. It also improves the miscibility of cellulose nitrate and resin solutions and helps maintain homogeneity during drying of lacquers. Reaction of cyclohexanol with ammonia produces cyclohexylamine [108-91-8], a corrosion inhibitor. Cyclohexanol is used as a stabilizer and homogenizer for soaps and synthetic detergent emulsions. It is used also by the textile industry as a dye solvent and kier-boiling assistant (see Dye carriers). 

In 1862 the Great International Exhibition was held in London and was visited by six million people. At this exhibition a bronze medal was awarded to Parkes for his exhibit Ptu kesine. This was obtained by first preparing a suitable cellulose nitrate and dissolving it in a minimum of solvent. The mixture was then put on a heated rolling machine, from which some of the solvent was then removed. While still in the plastic state the material was then shaped by dies or pressure . In 1866 the Parkesine Co., Ltd was formed but it failed in 1868. This appears in part due to the fact that in trying to reduce production costs products inferior to... 

It will be observed from Table 22.1 that industrial cellulose nitrates or nitrocellulose (as they are often erroneously called) have a degree of substitution somewhere between 1.9 and 2.7 and that materials with lower degrees of substitution are used for plastics applications. 

Plasticised amorphous thermoplastics Certain plastics may be mixed with high-boiling low-volatility liquids to give products of lower T. The most important example occurs with p.v.c. which is often mixed with liquids such as di-iso-octyl phthalate, tritolyl phosphate or other diesters to bring the below room temperature. The resultant plasticised p.v.c. is flexible and to some degree quite rubbery. Other commonly plasticised materials are cellulose acetate and cellulose nitrate. 

Tliere is another type of application where the damping effect of plastic structures can be used to advantage. It has a long although not obvious history. The early airplanes used doped fabric as the covering for wings and other aerodynamic surfaces. The dope was cellulose nitrate and later cellulose acetate that is a damping type of plastic. Conse-... 

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. 

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