Phase Relations in the Lanthanum Nitrate (Copper Nitrate)-Poly(vinylpyrrolidone)-Water Systems

摘要

Room-temperature isothermal sections of the phase diagrams of lanthanum nitrate-poly(vinylpyrrolidone)-water and copper nitrate-poly(vinylpyrrolidone)-water systems were studied. The following features were found: a wide region of homogeneous water-polymer solutions, liquid-liquid phase separation field, and a three-phase region in which two liquids coexist with salt crystals. In the lanthanum nitrate system, liquid-liquid phase separation has a lower critical solution point (polythermal sections were studied); in the copper nitrate system, it has an upper critical solution point. The type of diagram for unstudied systems is predicted based on the analysis of polymer-salt phase diagrams.