Coordination polymers. XV. Influence of diols on the reaction between unsaturated polyesters and Mg ions

Abstract

AbstractAn increase in viscosity of reaction mixtures of low molecular mass, COOH, and alcoholic OH‐terminated polyesters with MgO is considerably reduced by the presence of diols in the system. This effect is analogous with that described for the presence of water. Joint presence of water and diol results in an additive effect. The mechanism of this effect can be interpreted by coordination chemistry. In this system both diol and water saturate the coordination sphere of Mg2+ ion (as ligands). Consequently, the coordination of donor groups of polyester (terminal OH and ester carbonyl groups) is suppressed by reducing the extent of linking the polyester molecules with coordination bonds; that is, the average molecular mass of the system. Moreover, coordination of low‐molecular ligands modifies the final molecular structure that occurs in the system. In addition, some kinetic effects are revealed in the process because the system is diffusion‐controlled by the ever‐increasing viscosity. This effect is also favorable to the coordination of low molecular mass ligands. All of these factors lead to a reduction in the increase of viscosity in the present system.