Hydrophobically modified cellulose

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. 

Chem. Descrip. Ethyl hydroxyethyl cellulose, hydrophobically modified CAS 9004-58-4... 

Polymer polyacrylate, cellulose, hydrophobically modified cellulose Binder 1-35... 

A. Audibert, J. F. Argillier, L. Bailey, and P. I. Reid. Procedure and water-based fluid utilizing hydrophobically modified cellulose derivatives as filtrate reducer. Patent EP 670359, 1995. 

Dynamic Behavior of Hydrophobically Modified Hydroxyethyl Celluloses at Liquid/Air and Liquid/Liquid Interfaces... 

A new class of amphiphilic, surface-active graft copolymers, hydrophobically modified hydroxyethyl celluloses (HM-HEC s), are comprised of a cellulose backbone with short polyethylene oxide (PEO) and grafted alkyl side chains. They are excellent steric stabilizers of 0/W emulsions. 

The rheological properties of a fluid interface may be characterized by four parameters surface shear viscosity and elasticity, and surface dilational viscosity and elasticity. When polymer monolayers are present at such interfaces, viscoelastic behavior has been observed (1,2), but theoretical progress has been slow. The adsorption of amphiphilic polymers at the interface in liquid emulsions stabilizes the particles mainly through osmotic pressure developed upon close approach. This has become known as steric stabilization (3,4.5). In this paper, the dynamic behavior of amphiphilic, hydrophobically modified hydroxyethyl celluloses (HM-HEC), was studied. In previous studies HM-HEC s were found to greatly reduce liquid/liquid interfacial tensions even at very low polymer concentrations, and were extremely effective emulsifiers for organic liquids in water (6). 

Materials. Hydrophobically modified hydroxyethyl cellulose (HM-HEC) research samples were supplied by the Hercules Research Center. The compositions of the samples determined according to the preparation recipes, rather than by analysis, are summarized... 

A new class of water-soluble materials [10,11], was developed as a result of such design parameters that will be referred to as double substituted cationic cellulose ethers (DCEs). These materials contain both a cationic substituent and a hydrophobic substituent, attached to a cellulose ether backbone. The use of a double-substituted hydrophobe modified cationic polysaccharide is fundamentally different from current commercial vaginal formulations, which rely exclusively on nonionic or anionic vehicles. 

Hydrophobe modified carboxymethyl cellulose (D) reduces penetration (compare to B). 

Cationic/hydrophobe modified hydroxyethyl celluloses, (E) and (F), eliminate sperm penetration, even though they are not spermicidal. These DCEs physically impede sperm penetration, without affecting motility. 

Karlberg, M., Thuresson, K., Lindman, B. (2005). Hydrophobically modified ethyl (hy-droxyethyl)cellulose as stabilizer and emulsifying agent in macroemulsions. Colloids and Surfaces A Physicochemical Engineering Aspects, 262, 158-167. 

THE SYNTHESIS OF HYDROPHOBE-MODIFIED HYDROXYETHYL CELLULOSE POLYMERS USING PHASE TRANSFER CATALYSIS... 

Figure 2 The distance dependence characterizing exclusion of small solutes from macromolecular surfaces follows the same exponential behavior as the hydration force between macromolecules. The extent of exclusion can be extracted from the dependence of forces on solute concentration. ITexcess is the effective osmotic pressure applied by the solute in the bulk solution on the macromolecular phase, and np is the maximal pressure from complete exclusion, riexcess/rio = 1 then corresponds to complete exclusion and n excess/Ho = 0 means no inclusion or exclusion. The distance dependent exclusion the polar polyols adonitol (A) and glycerol ( ) from hydrophobically modified hydroxypropyl cellulose (FIPC) and of the nonpolar alcohols i-propanol ( ) and methyl pentanediol (MPD) ( ) from spermidine +-DNA is shown. As in Fig. 1, interaxial spacings are converted to surface separations. The apparent exponential decay length varies between 3.5 and 4 A (solid lines indicate fits to the data).

Nonionics (e.g., hydrophobically modified hydroxyethyl cellulose, HMHEC) Synthetic... 

Fabric and color care are areas that have received considerable emphasis over the past decade. The introduction of hydrophobically modified cellulosics (Liquifiber), multiple variants based upon derivatives of PVP technology for dye transfer inhibition, and a wealth of recent patent applications on polymeric additives to improve... 

Amphiphilic polymers can have a strong impact on the phase behaviour of microemulsions already at very low concentrations. The most drastic consequence is that on the emulsification capacity of surfactants. A first work in this respect was carried out using hydrophobically modified ethyl hydroxyethyl cellulose [ 1 ]. This is a comb-shaped polymer, having a water-soluble backbone functionalised with low molecular weight hydrophobic... 

FIG. 11 Pseudophase diagram for 30 wt% cyclohexane in water stabilized by PAA (Carbopol 980). The c values are shown as the curve drawn in the bottom left-hand corner of the diagram. (Reprinted from Colloids and Surfaces A Physicochem Eng Aspects, 88, Lockhead RY, Rulinson CJ, An investigation of the mechanism by which hydrophobically modified hydrophilic polymers act as primary emulsifiers for oil in water emulsions. 1. Poly(acrylic acids) and hydroxyethyl celluloses. 27-32, Copyright (1994), with permission from Elsevier Science.)... 

Lochhead RY, Rulinson CJ. An investigation of the mechanism by which hydrophobically modified hydrophilic polymers act as primary emulsifiers for oil in water emulsions. 1. Poly(acrylic acids) and hydroxyethyl celluloses. Colloids Surfaces A Physicochem Eng Aspects 1994 88 27-32. 

L Jamstrdm, L Lason, M Rigdahl, U Erikson. Flocculation in kaolin suspensions induced by modified starches 2. Oxidized and hydrophobically modified oxidized starch in comparison with poly(vinyl alcohol) and carboxymethyl-cellulose. Coll Surf A 104 207-216, 1995. 

The subject of surfactant-modified, water-soluble polymers, briefly discussed in Water-Soluble Polymers, is addressed in the last three sections (Chapters 16-28) of this book. These associative thickeners are covered in detail, ranging from the maleic acid copolymers of variable compositions introduced in various commercial markets in the early 1960s to the most recent entries (that is, in the open literature), hydrophobe-modified poly (acrylamide). Chapter 23 is complementary to the spectroscopic studies in Chapters 13-15 it explores new approaches to understanding associations in aqueous media. The three hydrophobe-modified polymers that have gained commercial acceptance in the 1980s, (hydroxyethyl)cellulose, eth-oxylate urethanes, and alkali-swellable emulsions, are discussed in detail. In particular, hydrophobe-modified (hydroxyethyl)cellulose, which is... 

---