Hydrophobically modified ethyl cellulose

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. 

A series of membrane materials have been tested for the performance of water removal from hydrazine, including poly(vinyl alcohol) (PVA), ethyl cellulose, PS, and ABS (93). Contact angle measurements served to estimate the hydrophilic or hydrophobic properties. Apolar materials showed higher separation factors than polar materials. Encouraging results with respect to the performance were obtained with modified ethyl cellulose and ABS membranes. 

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... 

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. 

Viscosity Maxima. The low-shear-rate viscosities of both commercial and model associative thickeners below their c /, values will increase with the addition of conventional low molecular weight surfactants or coalescing aid (22). With HEUR polymers, solution viscosities are observed to increase, achieve a maximum value, and then decrease with continued increase in surfactant concentration (23). This type of behavior is illustrated (Figure 5) for four commercial HEURs with a nonionic surfactant (typical of that used in coating formulations). A similar behavior has been observed (24) with a classical anionic surfactant and hydrophobically modified (hydroxy-ethyl)cellulose (HMHEC) and is reviewed in Chapter 18. Intermicellar networks, formed by the participation of one or more hydrophobes from different polymers in the micelles of conventional surfactants, were again recently suggested (25) to affect viscous solutions. 

The addition of A-380 of 0.5-2.5 wt.% reduces the adhesion (Table 37.15) and this may be caused by weak interaction between the hydrophilic silica particles and the hydrophobic CH groups of ethyl cellulose. This assumption is supported by the increase in adhesion after the addition of modified silica. When TS are used as an additive, the adhesion increases for C< 1 wt.%, but for... 

Non-ionic, hydrophobically-modified hydroxy ethyl cellulose (HMHEC). 

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

There are three main classes of thickeners, which are commonly used CeUulosics (modified natural products, usually hydroxy-ethyl cellulose - HEC), HASE (hydrophobic-ally modified alkali-sweUable emulsions) and HEUR (hydrophobically modified ethylene oxide urethanes). 

Figure 20.9. Cellulose can be modified by a relatively random substitution of hydroxyethyl and ethyl groups to give ethylhydroxyethyl cellulose (EHEC). In HM-EHEC, a low fraction of hydrophobic groups is inserted...

The hydrophobieally modified cellulosics consist of hydroxyethyl cellulose-based products, the first commercial associative thickeners, and more recently ethyl hydroxyethyl cellulose-based products. Relatively low molecular weight grades of the cellulosics are used, and these are modified via available hydroxyl groups on the polymer backbone. Hydrophobe substituents are one or two ethylene oxide imits terminated with an alkyl or alkylaryl group. The hydrophobe modification makes these cellulosics more Newtonian for better film build and leveling. 

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