Solution properties polyethylenimines

More recently, composite membranes have been made by interfacial polymerization or by in situ polymerization A representative case is illustrated in F. 8. Here, a microporous polysulfone membrane is used as a substrate. This membrane is soaked in a dilute aqueous solution of a low molecular weight polyethylenimine (PEI). Without drying, this membrane is then contacted with a crosslinking agent such as toluene diisocyanate (TDI) or isophthaloyl chloride dissolved in hexane, after which the membrane is cured in an oven. A highly crosslinked, salt-rejecting interfacial layer is formed in this way. A summary of the properties of three of the more important composite membranes is presented in Table 10. 

Radeva, T. and Petkanchin, I., Electric properties and conformation of polyethylenimine at the hematite-aqueous solution interface, J. Colloid Intetf. Sci., 196, 87,1997. Ozaki, M., Kratohvil, S., and Matijevic, E., Eormation of monodispersed spindle-type hematite particles, 7. Colloid Interf. Sci., 102, 146, 1984. 

Branched polyethylenimine (BPEI) is a strong polybase even at high ionic strength [79, 80] and forms complexes with acids. Its behavior is determined by properties such as the branched structure, presence of three different types of amine groups, strong neighboring interactions between various amine groups, and the compact structure in aqueous solution. 

Skachkova AL, Golub TP, Sidorova MP, Omarova KI, Musabekov KB. Elec-trokinetic and adsorption properties of Si02 in OP-7 and polyethylenimine solutions. Colloid J 1991 53 1100-1105. 

Grishina N.V., Rogacheva V.B., Lopatina L.I., Zezin A.B., Kabanov V.A., Transformation of the structure and properties of a complex of poly(acrylic acid) and Unear polyethylenimine during intracomplex amidation in aqueous solutions, Vysokomol. Soedin., SeriyaA, 27(6), 1985, 1154—1159. 

An important property of polyethylenimine is its solubility in water in all proportions and the material finds application mostly in the form of aqueous solutions. Typical uses are in the treatment of paper and textiles, for which the cationic polymer has great affinity. 

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