Nonionic cellulose ethers

Properties. Hydroxypropylcellulose [9004-64-2] (HPC) is a thermoplastic, nonionic cellulose ether that is soluble in water and in many organic solvents. HPC combines organic solvent solubiUty, thermoplasticity, and surface activity with the aqueous thickening and stabilising properties characteristic of other water-soluble ceUulosic polymers described herein. Like the methylceUuloses, HPC exhibits a low critical solution temperature in water. 

Nonionic cellulose ethers, hydroxyethyl(HE) and hydroxypropy1 (HP) cellulose, of variable molar substitution (M.S.) levels, were adsorbed on peptized sodium montmorillonite surfaces from fresh and saline (NaCl) aqueous solutions. The amounts adsorbed for 2 M.S. HEC and HPC and 4 M.S. HEC were insensitive to electrolyte concentration the 4 M.S. 

Figure 4 Adsorption (g/g) dependence of nonionic cellulose ethers (2500 ppm) on salinity (N, NaCl) of aqueous solution.

Figure 9 Adsorption (rag/g) dependence of nonionic cellulose ethers (2500 ppm) on salinity (N, NaCl) of aqueous solution. Substrate Berea sand (85 wt.%) blended with montraorillonite (15 wt.%). W-SP symbols ...

The nonionic cellulose ethers have been found suitable for use with synthetic fibers [3, 4]. 

Hydroxyethyl cellulose (O Fig. 24) is a nonflocculating, nonionic cellulose ether that has side chain extensions expressed in MS/DS-ratios of about 1.5 to 3.5. HECs are used in latex paints owing to their excellent interaction ability with solids. 

Hydrophobically modified nonionic cellulose ethers or poly(ethylene oxide) (HMPEO) act as unique stabilizers in suspension polymerization of vinyl and acrylic monomers (IS). The use of HMHEC as a stabilizer in emulsion polymerization of vinyl and allylic monomers has also recently been reported (16). 

Momcilovic et al. were able to significantly enhance sensitivity by labeling partially depolymerized nonionic cellulose ethers with dimethylamine. It is also possible to introduce a permanent charge directly, as reported for oligosaccharides, for... 

C. Alvarez-Lorenzo, R. A. Lorenzo-Ferreira, J. L. Gomez-Amoza, R. Martinez-Pacheco, C. Souto, and A. Concheiro, A comparison of gas-liquid chromatography, NMR spectroscopy and Raman spectroscopy for determination of the substituent content of general nonionic cellulose ethers, J. Pharmaceut. Biomed. Anal, 20 (1999) 373-383. 

This nonionic cellulose ether is soluble in cold water, ethanol, and mixtures of ethanol and water. 

Carlsson, A., Karlstrom, G. and Lindman, B., Thermal gelation of nonionic cellulose ethers and ionic surfactants in water. Colloids Surf., 47, 147-165 (1990). 

Scherlund, M., Malmsten, M. and Brodin, A., Nonionic cellulose ethers as potential drug delivery systems for periodontal anaesthesia, J. Colloid Interface Sci., 229, 365-374 (2000). 

Figure 20.33. The extension of an adsorbed polymer layer can be strongly modified on the association of an ionic surfactant due to electrostatic interactions. On addition of an ionic surfactant (sodium dodecyl sulfate) (SDS) to an adsorbed layer of a nonionic cellulose ether (ethylhydroxyethyl cellulose) (EHEC) there is a dramatic increase in the thickness of the adsorbed layer (filled circles) while there is little change in the total adsorbed amount (open circles). (By courtesy of Fredrik Joabsson)...

The raw materials are cotton linters, soft wood pulp or dissolving pulp. They must be high in alpha - cellulose content, free of metals and uniformly absorb water and the NaOH solution. The other starting materials include alkylene oxides and alkyl chlorides for the preparation of nonionic cellulose ethers and sodium monochloroacetate for anionic types such as sodium carboxymethyl cellulose. 

Thuresson K, Nilsson S, Lindman B. Influence of cosolutes on phase behavior and viscosity of a nonionic cellulose ether. The effect of hydrophobic modification. Langmuir 1996 12 2412-2417. 

SA1 Samii, A. A., Karlstidm, G., and Lindman, B., Phase behavior of a nonionic cellulose ether in nonaqueous solution, Langmuir, 1,653, 1991. 

In the present study, hydrophobic interaction between hydroxypropylcellulose (HPC) and an ionic surfactant in an aqueous phase was discussed. HPC, as well as EHEC, is a nonionic cellulose ether which contains hydrophobic groups in its molecular structure. Therefore, it might be interesting to compare the complex-formation properties of HPC with that of EHEC. The surfactants used here were an anionic surfactant SDS and a cationic one cetylpyridinium chloride (CPC). HPC formed a complex with these surfactants, of which cloud point changed with the surfactant concentration in the same manner as that observed in the EHEC-surfactant systems [4]. Effects of the complex on stability of dilute and concentrated kaoiinite suspensions were also studied, taking physicochemical properties of the complex into account. 

Cutter, C. N. and Sumner, S. S. Protein-basedfilms and coatings. A. Gennadies (Ed.), Application of edible coatings on muscle foods, CRC Press, Boca Raton, Florida, 467 88 (2002). Krumel, K. L. and Lindsay, T. A. Nonionic cellulose ethers. Food Technology, 30,36-38 (1976). 

We have successfully made networks of this type using hydrophobically modified hydroxyethyl cellulose (HMHEC), a nonionic cellulose ether, in two types of aqueous solvents, surfactant/water solutions and ethanol/water solutions. We have uncovered relationships between the solvent composition and the extent of cluster formation as well as the cluster composition. And we have fpund that we can indeed obtain higher loading of hydrophobic solutes than would be expected in equivalent volumes of water. 

The value of the exponent of NaCMC dissolved In 0.1 M NaCI shows that the shape of the molecule is probably similar to that of the nonionic cellulose ethers in water. In contrast, the increase in this exponent, in going to 0.01 A/f and 0.001/W NaCI, Indicates transition from coil to rodlike form. In reality, thermodynamic data indicate that cellulose chains may not be as stiff as they are assumed to be, on the basis of their high exponents in the intrinsic viscosity-molar mass relationship [20]. 

Swelling and viscosity of nonionic cellulose ethers are not affected by pH changes In the range of 2 to 12. In contrast, swelling and viscosity are maximum at neutrality for NaCMC and below about pH 3, the insoluble acid form precipitates (intrinsic pK values of 3.40 [21] and 3.70 to 4.30 [22] have been reported). 

Water-borne paint. Mainly nonionic cellulose ethers are used as rheology modifiers for water-borne paint. The rheology control of the paint influences such properties as paint consistency, brush load, levelling, sagging and hiding power. Besides the thickening, the polymer takes an active part in the particle stabilization in the paint. This is by far the most important application for a hydrophobically modified cellulose derivative (HM-CD). 

Thuresson, K., Nilsson, S. and Lindman, B. (1995) Effects on phase behaviour and viscosity of hydrophobically modification of a nonionic cellulose ether. Influence of cosolutes, in Cellulose and Cellulose Derivatives Physico-chemical Aspects and Industrial Applications (eds J. F. Kennedy, G. O. Phillips, P. A. Williams and L. Piculell), Woodhead Publishing Ltd, Cambridge, pp. 323-329. 

Thuresson, K. and Lindman, B. (1999) Association in nonionic cellulose ether solutions due to microcrystallites. Colloids Surf. A Physicochem. Engng Aspects, 159 (1), 219-226. 

MC, HPC and HPMC, nonionic cellulose ethers, are commercially available in powder or granular form, and in varying molecular weights and DS. They are insoluble in hot water but are soluble in cold water and organic solvents (solubilitacion of MC in organic solvents depends of the degree of substitution, under 2.6 DS is partially soluble and upper 2.6 DS is complete soluble). 

MC, HPC and HPMC are water soluble ethers with good film-forming properties. In order to avoid the formation of agglomerates the dissolution of these nonionic cellulose ethers must be done in two steps dispersion and hydration. Wherever possible, they should be put into solution before other soluble ingredients are added or should be dispersed in water miscible nonsolvent such as glycerol, ethanol or propylene glycol and then add the slurry to water. The solutions of these cellulose ethers are stable at pH 2-11 and are compatible with surfactants, other water-soluble polysaccharides, and with salts. 

The procedure for the preparation of clear CMC solutions follows that of the nonionic cellulose ethers, except for pH conditions. CMC solutions are only stable at pH 7-9. CMC is compatible with a wide range of other food ingredients including protein, sugar, starches and others hydrocolloids. 

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