In terms of the known concepts about noncovalent bonds in polycomplexes, the unusual case of interaction between positively charged aluminoxane particles (AP) $ 4.6 nm in size, which comprise the main portion of the dispersed phase in the sols of poly(aluminum hydroxychloride) (PAHC), and weakly charged cationic polyelectrolytes from the Praestol, Organopol, and Zetag series (WCPE) has been examined. Using viscometry, turbidimetry, and elemental analysis, it has been found that interaction between these compounds proceeds if the content of cationic groups in the polyelectrolyte is small and ions of a low-molecular-weight electrolyte occur in solution. Under the given conditions, the electrostatic repulsion of likely charged reagents does not manifest itself but other kinds of noncovalent interactions are realized that lead to formation of water-soluble polymercolloid complexes (PCCs). Fully charged polyelectrolytes are incapable of such interactions because of a strong electrostatic repulsion of reagents. The scheme illustrating formation of PCC has advanced. V C 2011 Wiley Periodicals, Inc. J Appl Polym Sci 121: [475][476][477][478][479][480][481][482] 2011
The rheological behavior of hybrid hydrogels of weakly charged polyelectrolytes with alumino xane particles (APs) formed by noncovalent interactions has been studied. This interaction observed for the polyelectro lyte Praestol-2500 is the most pronounced and is due to strong electrostatic noncovalent bonds between positively charged APs and anionic groups of the copolymer. By the methods of capillary, rotational, and vibrational rheo metry, it has been ascertained that two processes compete: the co mpacting of coils of macro molecu les and their crosslinking through APs. The latter process dominates at relatively high concentrations of reagents, and depends on ratios between polymer units and APs and the presence of a low-molecular-mass indifferent electrolyte (NaCl). Formed hybrid hydrogels relate to physical gels with the unstable nature of the network o f physical bonds, and under the action of shear stress demonstrate "Weissenberg effect." The method of dynamic mechanical analysis with the use of a micro-Fourier rheo meter has shown that the ratio storage modulus -loss modulus depends on the amount of AP sol and its ratio to the quantity of copolymer in the init ial mixture. A scheme for spatial structure hybrid hydrogels has been suggested.
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