2-Hydroxyethylcellulose

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. 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.  

By the action of relatively small quantities of sodium chloroacetate on alkali cellulose, carboxymethyl ethers are obtained which give smooth solution in dilute alkali but which can be regenerated to give threads or films of high tensile strength. These products are relatively hygroscopic. The substances are soluble in the form of their sodium salts and form insoluble salts with many metals.  

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Manufacture. Purified hydroxyethylcellulose is manufactured in diluent-mediated processes similar to those used to produce carboxymethylceUulose except ethylene oxide [75-21-8] is used in place of MCA (63,64) ... 

Specifications and Standards Test Methods. Hydroxyethylcellulose is included in the Hst of materials that are in compHance with requirements of the U.S. EDA for use in adhesives and in resinous and polymeric coatings employed on the food-contact surfaces of metal, paper, or paperboard articles, and other substrates intended for use in food packaging as specified in CER 21. HEC made dispersible by cross-linking with glyoxal is cleared only as an adhesive and as a component of paper and paperboard in contact with food. It has not been cleared as a direct food additive. 

Cationic Hydroxyethylcelluloses. These materials are manufactured by Union Carbide Corp. and National Starch and Chemical Corp., marketed under the trade names Polymer JR and Celquat, respectively (47,48). The cationic substituent on Polymer JR is presumably 2-hydroxypropyltrimethylammonium chloride (72). Celquat is presumably the reaction product of HEC with /V,/V-dia11y1-/V,/V-dimethy1ammonium chloride (73). Their primary appHcation is in shampoos and hair conditioners wherein the cationic moiety imparts substantivity to hair. Some typical properties of Celquat resins are given in Table 7. 

Other components in PVAc-formulations are defoamers, stabilizers, filler dispersants, preservatives, thickeners (hydroxyethylcellulose, carboxymethylcellu-lose), polyvinyl alcohols, starch, wetting agents, tackifiers, solvents (alcoholes, ketone, esters), flame retardants and others. 

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... 

Hydroxyethylcellulose with a degree of substitution of 1.1 to 1.6 has been described for fluid loss control in water-based drilling fluids [1473]. An apparent viscosity in water of at least 15 cP should be adjusted to achieve an API fluid loss of less than 50 ml/30 min. Crosslinked hydroxyethylcellulose is suitable for high-permeability formations [344,346]. 

A derivatized hydroxyethylcellulose polymer gel exhibited excellent fluid-loss control over a wide range of conditions in most common completion fluids. This particular grated gel was compatible with the formation material and caused little or no damage to original permeability [1341]. Detailed measurements of fluid loss, injection, and regained permeability were taken to determine the polymer particulate s effectiveness in controlling fluid loss and to assess its ease of removal. Hydroxyethylcellulose can be etherified or esterified with long chain alcohols or esters. An ether bond is more stable in aqueous solution than is an ester bond [96]. 

Hydro) thylcellulose R=(CH2CH20)m0H Carbo) ethylceiyose R=(CH2CO)OH Figure 2-3. Hydroxyethylcellulose, carboxymethylcellulose. 

Hydroxyethylcellulose can be chemically modified by the reaction with vinyl phosphonic acid in the presence of the reaction product of hydrogen... 

Fluidized aqueous suspensions of 15% by weight or more of hydroxyethyl-cellulose, hydrophobically modified cellulose ether, hydrophobically modified hydroxyethylcellulose, methylcellulose, hydroxypropylmethylcellulose, and polyethylene oxide are prepared by adding the polymer to a concentrated sodium formate solution containing xanthan gum as a stabilizer [278]. The xanthan gum is dissolved in water before sodium formate is added. Then the polymer is added to the solution to form a fluid suspension of the polymers. The polymer suspension can serve as an aqueous concentrate for further use. 

C. A. Lukach and J. Zapico. Thermally stable hydroxyethylcellulose suspension. Patent EP 619340, 1994. 

Leuco dye and coreactant are individually milled in an aqueous solution of binder such as poly(vinyl alcohol) or hydroxyethylcellulose by means of an attrition or sand mill until the particle size of the solid materials is about 1 pm or less in diameter. Smaller particles provide superior performance. 

Hydroxyethylcellulose HEC Water and GI fluids Properties similar to MC, but gives clear solutions... 

Another approach to improving the wettability of poorly soluble drugs is to treat the drug with a solution of a hydrophilic polymer. Lerk et al. [137] reported that both wettability of the powder and the rate of dissolution of hexobarbital from hard gelatin capsules could be greatly enhanced if the drug were treated with methylcellulose or hydroxyethylcellulose. In this process, called hydrophilization, a solution of the... 

Shellflo-XA, a proprietary grade of xanthan and cellobond X-100 a hydroxyethylcellulose (HEC) were used for comparative purposes. 

The main function of the foam stabilising agent is to reinforce the intercellular film wall by contributing rheological characteristics of viscoelasticity. The increased viscosity may also assist handling. The aim, as so often with auxiliaries, is to achieve an optimum balance. If the bubbles are too thin and wet too quickly they will collapse prematurely, whilst too stable a film could hinder uniform application. Examples of products used as foam stabilisers include thickening agents such as the polysaccharides, hydroxyethylcellulose, methylcellulose,... 

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