Cross-linked, hydrophobically associating homo- and copolymers were synthesized by free-radical cyclo(co)polymerization of alkylmethyldiallylammonium bromide monomers with a small amount of N,N'-methylenebisacrylamide in aqueous solution using ammonium persulfate as the initiator. The cross-linked homo- and copolymers showed a increase of their reduced viscosity in water and intrinsic viscosity in 1.0 M sodium chloride solutions upon the controlled introduction of crosslinking N,N'-methylenebisacrylamide into their chemical structure. Depending on the hydrophobic group content of the cross-linked copolymers, a conformational transition was revealed by viscosity measurements which is accounted for by intramolecular micelle formation and intermolecular aggregation. The hydrophobic microdomains of the cross-linked polysoaps were characterized by hypsochromic shifts of the long-wavelength absorption band of methyl orange as a solvatochromic probe, noncovalently bound to the macromolecule. Catalysis of the unimolecular decarboxylation of 6-nitrobenzisoxazole-3-carboxylate by the cross-linked copolymers was investigated in aqueous solution at pH 11.3 and 30 degrees C. The cross-linked polysoaps exhibited higher catalytic activities for decarboxylation than the corresponding non-cross-linked copolymer analogues. A maximum in rate constant was found at about 0.2% (w/w) of cross-linking agent in the cross-linked copolymers.
|Number of pages||6|
|Journal||Journal of Organic Chemistry|
|Publication status||Published - 29-Jul-1994|
- PHYSICAL ORGANIC-CHEMISTRY
- 6-NITROBENZISOXAZOLE-3-CARBOXYLATE ANION
- BENZISOXAZOLE-3-CARBOXYLIC ACIDS
- POLYMER COMPLEXES