Hydrophobically modified polyacrylamide

Castelletto, V., Hamley, I.W., Xue., W., Sommer, C., Pederson, J.S., Olmsted, P.D., 2004. Rheological and structural characterization of hydrophobically modified polyacrylamide solutions in the semidilute Regime. Macromolecules 37, 1492—1501. 

Although in pxinciple associative thickenos could be prepared from any water-soluble polymer to which hydrophobic blocks can be attached, only three types are commercially available at present hydrophobe-modified polyfetl lene oxide), hydrophobe-modified alkali-soluble acrylic polymers, and hydrophobe-modified hydroxyethyl cellulose. However, the literature contains reports on other types, including hydrophobe-modified polyacrylamide [103], hydrophobe-modified hydroxypropyl guar [104], and a hydrophobe-modified cationic cellulose... 

Effing JJ, Kwak JCT. 1995. Photoswitchable phase separation in hydrophobically modified polyacrylamide/surfactant systems. Angew Chem Int Ed Engl 34(1) 88 90. 

Biggs S, Selb J, Candau F. Effect of surfactant on the solution properties of hydrophobically modified polyacrylamide. Langmuir 1992 8 838-847. 

Candau F, Regalado EJ, Selb J (1998) Scaling behaviour of the ztao-shear viscosity of hydrophobically modified polyacrylamides. Macromolecules 31 5550-5552... 

Volpert, E., Selb, J., Candau, F, 1998. Associating behavior of polyacrylamide hydrophobically modified with dihexylacrylamide. Polymer 39, 1025—1033. 

A modified acrylamide polymer that is hydrophobically associating has remarkably improved the properties of salt resistance and temperature resistance, compared with high-molecular-weight polyacrylamide [1351]. 

Recently, such a procedure has been used by Wu and Shanks [22] upon a preparation of partially hydrophobized polyacrylamide (PAAm). In this work, the transamidation reaction has been employed to convert amide groups of the parent polymer to the alkylamide groups of the modified PAAm. Scheme 2 shows the reaction chart for the case of the N-isopropylamide derivative. 

Solute adsorption can be minimized most effectively by capillary wall coating, thereby decreasing the free energy of hydrophobic or ionic interactions. Coating can be achieved either by covalently bonded organic modifiers, e.g., polyacrylamides, sulfonic acids, polyethylene glycols, maltose, and polyvinyl pyrolidinone, or by dynamic deactivation (i.e., addition of... 

Fractionation of proteins according to size utilizing cross-linked dextran or polyacrylamide gel columns was first demonstrated by Porath and Flodin 63 in 1959. This technique has become the most widely accepted method for separation and molecular weight determination of hydrophilic and some hydrophobic macromolecules using aqueous buffers with or without organic modifier. While this technique might not be unique in its ability to resolve and separate proteins, it is one additional simple and effective tool in the chemist s armamentarium. The theories behind size-exclusion HPLC and size-exclusion chromatography at low pressure are identical and are described in several publications. 31 34 36 39 44 64 65 ... 

EOF can be suppressed by coating the channel surface with methylhydroxy-ethylcellulose (MHEC) [631], orphotopolymerized polyacrylamide [415]. Reversal of EOF was also achieved, e.g., the PMMA surface was modified with N-lithioethylenediamine or N-lithiodiaminopropane [1063] or the PDMS surface was coated by hydrophobic interaction with TBA+ [302]. 

---