Solution properties hydroxyethyl cellulose

Hydroxyalkylcellulose. Reaction of cellulose with ethylene or propylene oxides produces hydroxyethyl or hydroxypropyl derivatives. By forming the hydroxyethyl derivative about the same ratio of hydrogen bonding sites to carbon atoms is provided as in the underivatized cellulose, but the substituent groups reduce the fit between polymer chains so that the derivative can be dissolved in water to produce stable solutions. The cellulose derivative has many of the solution properties of guaran. 

Synthesis and Solution Properties of Hydrophobically Modified (Hydroxyethyl)cellulose... 

A few years ago, Landoll (2-4) reported that grafting a small amount of long-chain alkyl hydrophobes onto a nonionic water-soluble polymer leads to associative thickening behavior (i.e., enhanced viscosity, surface activity, and unusual rheological properties). This chapter deals with the general methods of preparation and solution properties of hydrophobically modified nonionic WSPs. Particularly described are the solution properties of hydrophobically modified (hydroxyethyl)cellulose (HMHEC) in aqueous and surfactant systems. 

This chapter is concerned with just one of this class of thickeners, namely a hydrophobically modified (hydroxyethyl)cellulose (HMHEC), Hercules WSP D-47. Gelman and Barth (i) reported on the viscosity of such HMHECs. This sample contained up to four hexadecyl chains grafted to the cellulose backbone. The preparative route was that described by Landoll (2). The dilute solution properties were characterized by capillary viscom-etry, whereas the more concentrated solutions were characterized by continuous-shear viscometry, forced oscillation measurements, and shear-wave propagation. In addition, the adsorption onto polymer latex particles was investigated. 

As with the alkylated polysaccharides, the physicochemical properties of hydroxyalkylated polysaccharides have continued to be investigated, particularly those of commercial value. The general characteristics of 0-(2-hydroxyethyl)cellulose have been described, together with pro-cedmes for the viscosimetric measurement of solutions of the polymer, and the macromolecular properties of the polymer in solution, described earlier, have been reviewed. The effect of increasing the substitution of both water-soluble 0-(2-hydroxyethyl)- and 0-(2-hydroxypropyl)-cellulose is to decrease their afiBnities for water. Water-soluble 0-(2-hy-droxypropyl) cellulose can be fractionated in a way analogous to that for O-methylcellulose by utilizing solvent—nonsolvent mixtures. For polysac-... 

GAO Gao, W., Liu, X.M., and Gross, R.A., Determination of molar mass and solution properties of cationic hydroxyethyl cellulose derivatives by mrrlti-angle laser light scattering with simultaneous refractive index detection, Polym. Int., 58, 1115, 2009. 

In addition to solution viscosity, interfacial surface tensions have also been measured as a function of polymer concentration [7]. In general, the polyacrylamides did not significantly change the surface tension of water over the concentration range of interest. On the other hand, the hydroxyethyl celluloses did lower the interfacial surface tension of water by about 5 percent over the concentration range of interest. Other than solution viscosity and surface tension, all other physical properties of the solvent have been assumed to remain unchanged at the very low polymer concentrations used in these experiments. ... 

A systematic study has been reported concerning the influence of the specific water structure and diphylic nature of some cellulose ethers (methyl-, methyl-hydroxypropyl-, hydroxypropyl-, hydroxyethyl-, and hydroxyethylhydroxy-propyl-) on the properties of the aqueous solutions of these polysaccharide derivatives. The presence of non-polar groups in the cellulose ether macromolecule and of associated specific water structures account for the solution properties given by hydrophobic hydration and hydrophilic bonds. 

Thuresson, K., B. Nystroem, G. Wang, and B. Lindman (1995). Effect of surfactant on structural and theimo-dynamic properties of aqueous solutions of hydrophobically modified ethyl (hydroxyethyl) cellulose. Langmuir 11(10) 3730-3736. 

We present herein a review of recent studies describing the preparation and properties of dispersed-phase solutions and hydrogels made from hydrophobically modified hydroxyethyl cellulose (HMHEC). 

Mixed ethers of ethyl and hydroxyethyl cellulose (EHEC) with an ethyl DS 1 and a hydroxyethyl MS of 0.5-2 have properties like hydroxyethylated or hydroxypropylated MC and are used in similar applications. They have a gelling temperature of 65-70 C in aqueous solutions, Due to the high degree of - etherification, they are resistant to biodegradation. 

Hydroxyethylmethyl cellulose is used as an excipient in a wide range of pharmaceutical products, including oral tablets and suspensions and topical gel preparations. It has similar properties to methylcellulose, but the hydroxyethyl groups make it more readily soluble in water and solutions are more tolerant of salts and have a higher coagulation temperature. 

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