Polyelektrolyte durch assoziat‐bildung von amylose mit azo‐farbstoffen

Abstract

dem verdienten Forscher und Lehrer auf dem Gebiet der Makromolekule, rnit besten Wiinschen zum 70. Geburtstag gewidmet (Eingangsdatum: 3. Oktober 1975) ZUSAMMENFASSUNG :Die Wechselwirkung bestimmter Azofarbstoffe rnit Amylose in wal3riger Losung fuhrt zu starken hderungen der optischen Drehung (induzierte Cotton-Effekte) und zu einem Anstieg der spezifischen Viskositat. Amylose verhalt sich in Gegenwart von z. B. Kongorot (1) oder Diaminechtrot (2) wie ein Polyelektrolyt. Diese Erscheinungen werden rnit der Bildung raumlich geordneter Assoziate zwischen Amylose und Farbstoff-Molekulen erklart. Andere Farbstoffe (z. B. Azoblau (3) und Calcon (4)) haben weder EinfluD auf die Viskositat noch auf die chiroptischen Eigenschaften. Offensichtlich fehlen in diesen Fallen die erforderlichen strukturellenVoraussetzungen fur die Bildung von Assoziaten. Farbstoffe, die bei Amylose Cotton-Effekte induzieren und die Viskositat verandern, bilden mit Polyvinylalkohol thermoreversible Gele. SUMMARY:The interaction of certain azo dyes with amylose in aqueous solution is the cause of strong changes of optical rotation (induced Cotton-effects) and of an increase of specific viscosity. Amylose in the presence of Congo Red (1) or Benzo Fast Red F (2) behaves like a polyelectrolyte. These findings are explained in terms of sterically ordered association between amylose and dye-stuffs. Some other dyes (i.e. Azoblue (3) or Calcon (4)) have no influence neither on the viscosity nor on the chiroptical properties. Obviously in these cases the structural requirements for association are not fulfilled. Those dyes which induce Cotton effects and change the viscosity of amylose, form thermoreversible gels with poly(viny1 alcohol).

Vinyl Alcohol Polymers

“…Congo red, for example, yields a red gel that melts sharply at about 40 • C. Other organic compounds that form a temperature reversible complex with PVA include azo dyes, resorcinol, catechol, and gallic acid (133,134) Fully hydrolyzed PVA and iodine forms a complex that exhibits a characteristic blue color similar to that formed by iodine and starch (135)(136)(137). The color of the complex can be enhanced by the addition of boric acid to the solution consisting of iodine and potassium iodide.…”

Binding of chrysophenine G by methyl cellulose and poly(vinyl alcohol)

“…However, to estimate the character of the binding of dyes with polymer chains themselves, 1860 SHIBUSAWA, TANAKA, AND YAMAGUCHI the binding of direct dyes by polysaccharides (model compounds of cellulose) in water have often been studied by an optical method from the spectral change of the dyes due to the binding. [5][6][7][8] In those studies, the dyes having the highest class of affinity on cotton, e.g., Congo Redg and Benzopurprine 4B7 were used. These dyes aggregate highly in water, particularly in the presence of electrolytes a t low temperature."…”