Polyurethanes, hydrophobically modified

Hydrophobically modified ethoxylated urethane thickeners, also known as polyurethane thickeners, are a more recent type of asso-... 

It is, of course, possible to prepare a molecule that has both polar and nonpolar characteristics. This is the basis of surfactant chemistry. Typically, a nonpolar molecule is modified by sulfonation. The well-known Pluronic family of surfactants is based on block polymerization of polypropylene oxide (the hydrophobe) and polyethylene oxide (the hydrophUe). It is conceptually possible to build a polyurethane 2005 by CRC Press LLC... 

Surfactants Surfactants are molecules made up of a polar hydrophilic head group and a hydrophobic hydrocarbon tail, which leads these molecules to favor as being at the interface between two phases.31 Membranes that were previously used, such as solvent-cast cellulose acetate72 or dip-coated polyurethane membranes,73 can be modified by surfactants to decrease biofouling. Lindner et al. showed that membranes with lower surfactant plasticizer ratios exhibited lower anion interference and better biocompatibility.74... 

The high hydrophobicity of silicones can complicate their use in some applications. For example, proteins can undergo denaturation in contact with silicones [1]. In such cases, the siloxane can be modified to include a hydrophilic domain. This is typically accomplished by functionalizing the silicone with a hydrophilic polymer such as poly(ethylene oxide)(PEO). Silicone surfactants of this type have found widespread use as stabilizers for polyurethane foams, and have been investigated as a structurant to prepare siloxane elastomers for biomaterials... 

A recent example of XPS analysis of polyurethane surfaces has been provided by Yoon et al. [30]. In these studies polyurethanes were prepared with 4.4 -methylenebisfphenyl isocyanate) (MDI)and hexafluoro- l.5-pentancdiol (FP) extenders as the hard segment, and poly(tetramethylene glycol) (PTMO) as the soft segment. The authors introduced hydrophobic soft segments, either poly-(dimethylsiloxan) (PDMS) or polyisobutylene (PIB) into this polyurethane structure. The concept underlying this polymer design was the desire to modify sur-... 

Chem. Descrip. Hydrophobic polyether polyurethane polymer in water Uses Associative thickener, rheology modifier for aq. coatings Features Inc. high shear vise, of paint while not affecting the low shear vise. no VOC s... 

U-P[5F-co-HyOx] copolyoxetanes as surface modifiers. Validation of the model shown in Figure 10.2 was explored with 2 wt% U-P[5F-co-HyOx-66 23] and other huorous-hydantoin soft block polyurethanes as surface modihers for IPDI-BD-PTMO or HMDI-BD-PTMO base polyurethanes. Contraphihc wetting was not found. Rather, the resulting 2 wt% U-P[5F-co-HyOx-66 23] showed hydrophobic wetting behavior typical of polyurethanes with huorous soft blocks. The base... 

To make the modified surface properties (hydrophilic/hydrophobic) more permanent, siuface-modifying macromolecules (SMMs) were developed. SMM has an amphi-phatic structure consisting theoretically of a main polyurethane chain terminated with two low polarity polymer chains (i.e., fluorine segments) [65]. 

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