Cellulose alkyl ethers

Ethylcellulose. The cellulose ethers obtained by the alkylation of cellulose are important plastic materials. TTiey are more stable than the cellulose esters and are incapable of undergoing hydrolysis, which makes them more resistant to acid and alkalies. The alkyl ethers are, however, soluble to a considerable extent in waier and alkalies, more so than benzyl-cellulose but less than cellulose acetate. 

One- and two-dimensional NMR spectroscopy demonstrates the uniform structure of the 3-6>-alkyl ethers after peracetylation of the remaining OH groups as shown in Fig. 16.12 for 3-(9-methoxyethyl-2,6-di-0-acetyl cellulose as a typical example [89]. 

Petzold K., Klemm D., Heublein B., Burchard W., Savin G., Investigations on structure of regioselectively functionalized celluloses in solution exemplified by using 3-0-alkyl ethers and light scattering. Cellulose, 11, 2004, 177-193. 

Also (conveniently) in many cases, the surfactant system itself is self-thickening. This is especially the case with amine oxide/soap combinations that are used with hypochlorite bleach systems, as is well known, as well as variations on this theme [37], and amine oxide/soap systems that are shown to be supplemented by polymer [38], There is also a citation for a system using alkyl ether sulfate, solvent, and electrolyte to thicken the system [39], For systems with lower surfactant levels, sometimes the addition of polymers such as hydroxyethyl cellulose [40,41] or colloidal thickeners [42] are mentioned. The targets for these cleaners tend to be in the 200-1000 cP range, especially in the 300-700 cP range. 

Besides vinyl acetate monomer, three other components are neeessary to earry out an emulsion polymerization water, an emulsifier and/or a proteetive eolloid, and a water-soluble initiator. Most commonly, anionic long-chain alkyl sulfonates are used as surfactants in amounts up to 6%. Studies have shown that the rate of polymerization is dependent on the amoimt of emulsifier present, with the rates inereasing as the amoimt of emulsifier is increased up to a certain point and then falling olF as free-radieal ehain transfer to the surfaetant beeomes a serious competing side reaetion [240]. In general, surfactants are used in eombination with a protective colloid. Especially useful as protective colloids are poly(vinyl alcohol), hydroxyethyl cellulose, alkyl vinyl ether-maleic anhydride and styrene-allyl alcohol copolymers, and gum arable. Water-soluble initiators, particularly potassium persulfate, alkali peroxydisulfates, hydrogen peroxide, and various redox systems, are most commonly used. 

Adhesives are often based on blends to optimize the key properties of interest, but as they are often designed for specific applications, the blend compositions are rarely disclosed. However, a large number of patents exist related to adhesive compositions. Blends of alky(meth)acrylates and poly(vinyl alkyl ethers) were described for self-adherent (Tg < 10 °C) adhesives or hot melt adhesives for labels, adhesive tapes or films [171]. Hot melt adhesives based on a blend of poly(vinyl alcohol) and copolymers of alkyl(meth)acrylates and other vinylic monomers were described for paper, wood and other cellulosic articles [172]. The PVOH based hot melt adhesives offer the advantage of repulpability for paper/cellulosic products requiring adhesives. A waterborne adhesive for coating friable surfaces (e.g., chalky weathered paint or masonry) was described as comprising a blend of separate emulsion polymers [173]. The examples noted blends of a MMA-nBA-MAA emulsion terpolymers with MMA-nBA emulsion copolymer with the copolymer having a particle size less than 120 nm. 

The NOT operator excludes single search terms from retrieval. But mind its hidden dangers. If the search term is e.g. methyl cellulose and you exclude terms like ethyl cellulose, alkyl cellulose, etc., relevant documents might be forgone, where both methyl cellulose as well as other cellulose ethers are contained. Therefor you should be extremely careful when using the NOT operator. It is advisable to refine the search statement by further AND combinations. In any case, the amount of data to be excluded should be dealt with prior to other operations in order to check via titles, etc. if those documents should really be excluded by the NOT-operator. 

Carboxymethylcellulose, polyethylene glycol Combination of a cellulose ether with clay Amide-modified carboxyl-containing polysaccharide Sodium aluminate and magnesium oxide Thermally stable hydroxyethylcellulose 30% ammonium or sodium thiosulfate and 20% hydroxyethylcellulose (HEC) Acrylic acid copolymer and oxyalkylene with hydrophobic group Copolymers acrylamide-acrylate and vinyl sulfonate-vinylamide Cationic polygalactomannans and anionic xanthan gum Copolymer from vinyl urethanes and acrylic acid or alkyl acrylates 2-Nitroalkyl ether-modified starch Polymer of glucuronic acid... 

Various ether derivatives of cellulose, including some that are water-soluble, are important [Heinz and Liebert, 2001 Just and Majewicz, 1985 Zhang, 2001]. Methyl cellulose and car-boxymethyl cellulose (R = CH3 and CH2COOH, respectively) are synthesized by reaction of cellulose with sodium hydroxide followed by the appropriate alkyl halide ... 

Strong caustic solutions penetrate the crystal lattice of alpha cellulose and produce an alkoxide called alkali, or soda, cellulose. Mercerized cotton is produced by aqueous extraction of the sodium hydroxide from alkali cellulose fibers. Cellulose ethers and cellulose xanthate are produced by reactions of alkyl halides or carbon disulfide, respectively, with the alkali cellulose. 

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