Nonionic hydrophobes

Hydrophobic fibers are difficult to dye with ionic (hydrophilic) dyes. The dyes prefer to remain in the dyebath where they have a lower chemical potential. Therefore nonionic, hydrophobic dyes are used for these fibers. The exceptions to the rule are polyamide and modified polyacrylonitriles and modified polyester where the presence of a limited number of ionic groups in the polymer, or at the end of polymer chains, makes these fibers capable of being dyed by water-soluble dyes. 

Nonionic hydrophobic Polyvinylpyrrolidone Buffer or salt solution with organic solvent (e.g., 20% CH,CN in 0.1 M NaNOd... 

Nonionic hydrophobic Polyvinyl pyrrolidone 80/20 0.1 M NaNOj/CHjCN... 

Nonionic, hydrophobic Polyvinylpyrrolidone 0.1—3 M salt/buffer with 20% methanol... 

Table 2 Nonionic, Hydrophobic Monomers Used for Hydrogel Synthesis... 

For these reasons, the Kt approach works best for describing sorption of trace amounts of nonionized, hydrophobic organic molecules (Stumm and Morgan, 1996). The approach is broadly recognized to describe poorly the behavior of ionic species, especially metal ions, within soils and sediments (e.g., Reardon, 1981 Domenico and Schwartz, 1998). Nonetheless, it is commonly applied for just such purposes, often giving misleading results (Bethke and Brady, 2000). 

Mader, B.T., Uwe-Goss, K., and Eisenreich, S.J. Sorption of nonionic, hydrophobic organic chemicals to mineral surfaces. 

Molecular sieve adsorbents have been widely studied and employed to separate saturated, mono- and di-saturated fatty acids or to concentrate them in a mixture. Logan and Underwood (32) patented a method to use zeolite as the adsorbent to separate esters of fatty acids according to their degree of unsaturation. Use of nonionic, hydrophobic cross-linked polymers has also been successful in selective separation of fatty acids (33). The fatty acids are first allowed to adsorb onto the solid bed of a particular adsorbent and then the adsorbed acids may be desorbed by employing a suitable desorbent. 

Vinyl acetate is polymerized in dispersion form using various initiators. Exanples of ionic initiators commonly used for free-radical emulsion polymerizations are ammonium, sodium or potassium persulfate. Topical nonionic hydrophobic initiators include 2,2 -azobis(isobutyronitrile) (AIBN) and benzoyl peroxide. Water-soluble nonionic initiators such as tertiary-butyl hydroperoxide are also employed. The initiator 4,4 -azobis(4-cyanovaleric acid) in its acid state is oil soluble, while neutralization causes it to become water soluble providing for further diversity in initiators. 

Chem. Desa tp. Aq. sol n. of nonionic hydrophobe-modified polymer Uses Thickener for water-based paints, esp. acrylic, styrene-actylic, and vinyl-actylic systems... 

Chem. Descrip. Aq. soi n. of nonionic hydrophobe-modified poiymer Uses Thickener, fiow aid, ieveiing agent for waterborne paints/coatings, esp. for sm. particie size acryiic and styrene/acryiic disps. 

The use of biocompatible systems is proposed by Rajot et al. [76], who produced nonionic hydrophobic drugs such as indomethacin encapsulated in poly(vinyl acetate). In addition, oligocaprolactone macromonomers obtained by anionic coordinated ring-opening polymerization, benzyl benzoate, or triglycerides from fatty acids were used as the hydrophobe in order to obtain biocompatible systems. 

Ions with hydrophobic groups in their periphery around a buried charge, such as or (C4Hg)4N, are generally only poorly solvated. However, (QH5)4N and larger tetraalkylanunonium ions may have the water in clathrate-like or enhanced tetrahedral ice-like structures around them as for nonionic hydrophobic solutes. 

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