Cellulose nitrate polymer

Cellulose Deriva.tives, Cellulose can be derivatized to make both water-soluble gums and hydrophobic polymers. The preparation of the hydrophobic cellulose esters (qv), cellulose acetates and cellulose nitrates, has already been mentioned. The water-soluble cellulose derivatives are cellulose ethers (qv). 

Comparison of Table 5.4 and 5.7 allows the prediction that aromatic oils will be plasticisers for natural rubber, that dibutyl phthalate will plasticise poly(methyl methacrylate), that tritolyl phosphate will plasticise nitrile rubbers, that dibenzyl ether will plasticise poly(vinylidene chloride) and that dimethyl phthalate will plasticise cellulose diacetate. These predictions are found to be correct. What is not predictable is that camphor should be an effective plasticiser for cellulose nitrate. It would seem that this crystalline material, which has to be dispersed into the polymer with the aid of liquids such as ethyl alcohol, is only compatible with the polymer because of some specific interaction between the carbonyl group present in the camphor with some group in the cellulose nitrate. 

The doyen of the ester polymers is cellulose nitrate. Camphor-modified cellulose nitrate has been known for over 120 years and still retains its use in a few specialised applications. 

The stabilised nitrate may then be bleached with sodium hypochlorite, centrifuged to remove much of the water in which the polymer has been slurried and dehydrated by displacement with alcohol while under pressure in a press. It is interesting to note that in these processes approximately 35 000 gallons (160000 litres) of water are used for every ton of cellulose nitrate produced. Control of purity of the water is important in particular the iron content should be as low as 0.03 parts per million since iron can adversely affect both the colour and heat stability of the polymer. 

Cellulosic They are tough, transparent, hard or flexible natural polymers made from plant cellulose feedstock. With exposure to light, heat, weather and aging, they tend to dry out, deform, embrittle and lose gloss. Molding applications include tool handles, control knobs, eyeglass frames. Extrusion uses include blister packaging, toys, holiday decorations, etc. Cellulosic types, each with their specialty properties, include cellulose acetates (CAs), cellulose acetate butyrates (CABs), cellulose nitrates (CNs), cellulose propionate (CAPs), and ethyl celluloses (EC). 

Polyamide, collodion (cellulose nitrate), ethylcellulose, cellulose acetate butyrate or silicone polymers have been used for preparation of permanent microcapsules. This method offers a double specificity due to the presence of both the enzyme and a semipermeable membrane. Moreover, it allows simultaneous immobilization of many enzymes in a single step and the surface area for contacting the substrate and the catalyst is large. The need of high protein concentration and the restriction to low molecular weight substrates are the main limitations of enzyme microencapsulation. 

Whereas GALDI-MS detects low molecular weight synthetic resins, common synthetic polymers, such as various acrylic polymers, polystyrene, and cellulose nitrate, did not produce any mass spectra using this method. 

A literature survey ( 1 - 11) on the fractionation of cellulose triacetate by precipitation indicates that in most cases it has been unsuccessful due to the possibility of hydrogen bonding between polymer and solvent in solutions (10. 12). GPC has been applied to the fractionation of cellulose derivatives by many workers. Segal (13), Meyerhoff (14 - 16), Muller and Alexander (17) have reported the fractionation of cellulose nitrate by GPC. Muller and Alexander (17), Brewer, Tanghe, Bailly and Burr... 

Would you expect the addition of chlorine or hydrogen to a double bond in a polymer to occur 100% What is the DS of cellulose nitrate when it is used as an explosive ... 

Both cellulose and cellulose nitrate (CN) are linear, or two-dimensional, polymers, but the former cannot be softened because of the presence of multitudinous hydrogen bonds between the chain-like molecules. When used as an explosive the CN is essentially completely nitrated, but the material used by Parks and Hyatt was a dinitrate, still potentially explosive, but less so. Parks added castor oil and Hyatt added camphor to plasticize—reduce the effect of the hydrogen bonding—the CN, allowing it some flexibility. 

Figure 5. Cellulose nitrate and camphor, illustrating similarity between polymer and plasticizer...

All of the calculations were done by computer. The program, which is general and can be applied to polymers other than cellulose nitrate, is available on request. 

The acetates of most alcohols are also commercially available and have diverse uses. Because of their high solvent power, ethyl, isopropyl, butyl, isohutyl. amyl, and isoamyl acetates are used in cellulose nitrate and other lacquer-type coatings. Butyl and hexyl acetates are excellent solvents for polyurethane coaling systems, see also Urethane Polymers. Ethyl, isobulyl. amyl, and isoamyl acetates are frequently used as components ill llavoring. sec also Flavors and Essences, and isopropyl, benzyl, octyl, geranyl. linalyl. and methyl acetates arc important additives in perfumes. 

Allyl-diglycol-carbonate polymer Diallyl phthalate (DAP) polymer Cellulosics Cellulose acetate resin Cellulose-acetate-propionate resin Cellulose-acetate-butyrate resin Cellulose nitrate resin Ethyl cellulose resin Rayon... 

Membranes and composites from cellulose and cellulose esters are important domains in the development and application of these polymer materials. The most important segment by volume in the chemical processing of cellulose contains regenerated cellulose fibers, films, and membranes, hi the case of the cellulose esters mainly cellulose nitrate and cellulose acetate as well as novel high-performance materials created therefrom are widely used as laminates, composites, optical/photographic films and membranes, or other separation media, as reviewed in [1], The previously specified nanocelluloses from bacteria and wood tie in with these important potentials and open novel fields of application. 

As a matter of fact, mankind knows polymers from ancient times, due to the existence of naturally occurring polymers such as latex, starches, cotton, wool, leather, silk, amber, proteins, enzymes, starches, cellulose, lignin, and others. The other type of polymers are synthetic polymers. Braconnot, in 1811, perhaps made the first significant contribution to polymer science by developing compounds derived from cellulose. Later, cellulose nitrate was obtained in 1846 by Schonbein, afterward in 1872, its industrial production was established. Besides, in 1839, Goodyear found out by accident that by heating latex with sulfur its properties were altered creating a flexible and temperature-stable rubber. This process is named vulcanization. 

In micro- and ultrafiltrations, the mode of separation is by sieving through line pores, where microfiltration membranes filter colloidal particles and bacteria from 0.1 to 10 mm, and ultrafiltration membranes filter dissolved macromolecules. Usually, a polymer membrane, for example, cellulose nitrate, polyacrilonytrile, polysulfone, polycarbonate, polyethylene, polypropylene, poly-tretrafhioroethylene, polyamide, and polyvinylchloride, permits the passage of specific constituents of a feed stream as a permeate flow through its pores, while other, usually larger components of the feed stream are rejected by the membrane from the permeate flow and incorporated in the retentate flow [10,148,149],... 

The motivation to make derivatives of cellulose was the conversion of the intractable material into something that could be dissolved and then processed. As we just saw, cellulose acetate replaced cellulose nitrate in commercial motion picture film and was the only polymer ever used for home movie film. Edison introduced home moviemaking in this country in 1911. 

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