TERNARY INTERPOLYMER COMPLEXES WITH A LOW-MOLECULAR-MASS MEDIATOR - COMPLEX WITH DIPYRIDYL

The paper describes one representative of the class of ternary interpolymer complexes with a low-molecular-mass mediator, viz., a complex formed by two polyacids - poly(acrylic acid) and polyphosphate - and dipyridyl. By examining optical density D as a function of pH for aqueous solutions of dipyridyl-poly(acrylic acid) salts, dipyridyl-polyphosphate salts, and solutions containing all three components [sodium polyphosphate, poly(acrylic acid), and dipyridyl], it was found that, in the pH range from 1.15 to 4.9, the reaction between sodium polyphosphate, poly(acrylic acid), and dipyridyl results in an insoluble product, which was identified as a true ternary complex, rather than as a mixture of dipyridyl salts of the polyacids. This conclusion was supported in a comparative DSC study of ternary complexes and dipyridyl salts of poly(acrylic acid) and sodium polyphosphate. Taking into account the fact that the ratio of the constituent components in the ternary complex was independent of the preparation procedure (at a certain pH), the ternary complex was inferred to be an individual chemical compound characterized by constant composition.