Cellulose ethylcellulose

Following the first observation of mesophase formation of HPC/H2O, the rheology of this system has been widely investigated. Rheological studies of other cellulosic mesophases, e.g., cellulose, ethylcellulose, and cellulose tricarbanilate, have also been reported. 

The nanoyarn can be produced also from cellulose derivatives such as methyl-cellulose, ethylcellulose, nitrate cellulose, acetate cellulose, acetate-butyrate cellulose, etc. When, for instance, the nanoyam of acetate cellulose is produced, the initial polymer is dissolved in acetic acid, acetone, or ethylacetate (Stylianopoulos et al., 2012 Vargas, 2010). 

Some tablets combine sustained-release and rapid disintegration characteristics. Products such as K-Dur (Key Pharmaceuticals) combine coated potassium chloride crystals in a rapidly releasing tablet. In this particular instance, the crystals are coated with ethylcellulose, a water-insoluble polymer, and are then incorporated into a rapidly disintegrating microcrystalline cellulose (MCC) matrix. The purpose of this tablet is to minimize GI ulceration, commonly encountered by patients treated with potassium chloride. This simple but elegant formulation is an example of a solid dosage form strategy used to achieve clinical goals. 

Ethylcellulose is made commercially by the action of ethyl chloride on an alkali cellulose prepared by steeping cotton linters or wood pulp... 

The low-substituted hydroxyethylcellulose which, like methyl- and ethylcellulose, is soluble in alkali, particularly when cooled, has much to recommend it from an industrial point of view. It can be formed by the action of only small quantities (0.25 to 0.5 moles) of ethylene oxide on alkali cellulose.47 The reaction product need not be isolated since there are no salts formed, but may be diluted with water or weak alkali to give a spinning solution. The product should therefore be quite cheap. Preparation and properties of hydroxyethylcellulose have been discussed by Schorger and Shoemaker.47... 

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. 

Fig. 1 Chemical structures of the polymers commonly used for preparation of beads poly (styrene-co-maleic acid) (=PS-MA) poly(methyl methacrylate-co-methacrylic acid) (=PMMA-MA) poly(acrylonitrile-co-acrylic acid) (=PAN-AA) polyvinylchloride (=PVC) polysulfone (=PSulf) ethylcellulose (=EC) cellulose acetate (=CAc) polyacrylamide (=PAAm) poly(sty-rene-Wocfc-vinylpyrrolidone) (=PS-PVP) and Organically modified silica (=Ormosil). PS-MA is commercially available as an anhydride and negative charges on the bead surface are generated during preparation of the beads...

Uses Solvent for cellulose acetate, ethylcellulose manufacturing insecticides, ethylene oxide, and ethylene glycol treating sweet potatoes before planting organic synthesis (introduction of the hydroxyethyl group). 

Ethylcellulose or Eudra-git RS with galactoman-nans, p-cyclodextrin, glassy amylose, inulin Cellulose ethers, Eudragit sustained-release coatings... 

The success of prolonged-release morphine prompted the development of prolonged-release formulations for other opioids, for example the matrix made of hydrophobic and hydrophilic matrix formers, for example on hydrocodeine (DHC retard with cetostearyl alcohol and hydroxyethyl-cellulose), oxycodone (oxygesic with stearyl alcohol and polyacrylate) and tramadol (tramundin with cetostearyl alcohol and ethylcellulose). By virtue of the oblong shape of hydrocodeine and tramadol tablets the prolonged-release tablets can be divided, whereby compared with whole tablets release from the divided tablets is slightly accelerated. The difference with these forms is that with increasing dose the release slows down. 

Ethylcellulose [.9004-57-3 ], a cellulose either (qv), as prepared commercially, ie, of high DS, is thermoplastic and has a low density (1.14 g/cm3). It forms films of good thermostability and excellent flexibility and toughness. Ethylcellulose is used in lacquers, inks, and adhesives and is combined with waxes and resins in the preparation of hot-melt plastics. It is also used as a pharmaceutical tablet binder. 

Carboxym ethylcelluloses (CMC). Carboxymethylcellulose [9004-42-6] (CMC) is the carboxymethyl ether of cellulose. To prepare CMC, cellulose is steeped in sodium hydroxide solution, and the so-called alkali cellulose is treated under controlled conditions with sodium monochloroacetate to form the sodium salt of carboxymethylcellulose and sodium chloride. Therefore, the CMC of commerce is actually sodium carboxymethylcellulose... 

Tests for cellulose acetate, cellulose acetate butyrate, ethylcellulose and methylcellulose are given in Ref 6, Methods D8 17, D871, D914 D1347... 

US military requirements and tests for cellulose acetate, cellulose acetate butyrate and ethylcellulose are given in Refs 10, 11 12. There is n o USmilitarv specification for methylcellulose... 

D9 4(Tests for ethylcellulose) PI347(Tests for methylcellulose) 7)US Joint Army-Navy Specification JAN-C-206 Cellulose, Co ton(For Use in Explosives) 8)JAN-C-216 Cellulose,... 

Wood pulp(For Use in Explosives) 9)JAN-C-677 Cellulose, Regenerated Strip(For Use in Ammunition) 10)US Military Specification MIL-C-20301, Cellulose Acetate(For Use in Propellants) 11) MlL-C-5537A(l), Cellulose Acetate ButyratefFor Use in the Manufacture of Organic Protective Coatings) 12)MIL-E-L 0853B(Ethylcellulose)... 

Rapid method for the detn of N content in NC s by the ferrous ammonium sulfate method, using as the "standard a NC of known N content, previously detd by nitrometer) 19)K.Thinius, Farbe u Lack 56, 3-9(1950) CA 44, 4817 (1950)(Luminescence analysis for indentification of NC, cellulose, cellulose acetate, ethylcellulose methylcellulose) 20)L.B.Genung, AnalChem 22, 403(1950) CA 44, 6l21(1950)(Detn of N content by nitrometer) 21)R.Leclercq J. 

A possible way to lower the costs of fibers and films of regenerated cellulose would be to run cellulose through a twin-screw ultrasonic extruder with a minimum of solvent and pass the extrudate through a stream of hot air to recover the solvent for reuse. This stronger cellophane could be used in place of many plastic films used today. A great number of derivates of cellulose have been made. Methyl, ethyl, carboxymethyl, hydroxyethyl, and hydroxypropyl ethers are made commercially today. These are used as water-soluble polymers, except for ethylcellulose, which is a tough plastic used in screwdriver handles and such. 

Figure 1. ESR spectra of cellulose and cellulose derivatives irradiated with UV light of A > 280 nm for 60 min at 77 K. Spectra were recorded at 77 K. Key a, cellulose b, methylcellulose c, ethylcellulose d, acetylcellulose e, hydroxyethyl-cellulose f, carboxymethylcellulose.

Figure 8. Degree of grafting for cellulose and cellulose derivatives initiated by UV light of > 280 nm. Key a, fibrous carboxymethylcellulose b, cellulose c, hydroxyethylcellulose d, ethylcellulose e, methylcellulose f, powdered carboxymethylcellulose g, acetylcellulose.

The simplest representatives of cellulose ethers are the corresponding alkyl derivatives. The most common representatives manufactured industrially are methyl- and ethylcellulose. Methylcellulose is soluble in cold water when the DS is 1.4 to 2.0, whereas nearly completely substituted products (DS 2.4-2.8) are insoluble in water but soluble in organic solvents. 

Methylcellulose solutions generally form gels at higher temperatures. The gelation temperature is increased when hydroxyethyl or hydroxypropyl groups are introduced into the methylcellulose (cf. Section 9.6.2). Hy-droxyethylmethylcellulose and hydroxypropylmethylcellulose are prepared industrially by the reaction of alkali cellulose first with ethylene oxide or propylene oxide and then with methyl chloride. Similarly, hydroxyethyl-ethylcellulose is prepared by consecutive ethylene oxide and ethyl chloride treatments. Cellulose ethers with both methyl and ethyl groups have also been manufactured. 

Methyl-and ethylcelluloses are prepared by reacting purified woodpulp or cotton linters having a high a-cellulose content with aqueous sodium hydroxide and then with methyl chloride or ethyl chloride according to the following scheme ... 

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