Miscibility studies of poly(vinylpyrrolidone)/poly(vinyl alcohol) blends in water by viscosity, density, refractive index and ultrasonic velocity methods

Poly(vinylpyrrolidone) (PVP)/poly(vinyl alcohol) (PVA) are water-soluble polymer blends; they are used for food packaging, biomedical, and pharmaceutical applications. The miscibility of PVP/PVA blends in water was studied by viscosity, density, ultrasonic velocity, and refractive index techniques at 30°C and 50°C. Using viscosity data, the interaction parameters such as ΔB, μ and α were calculated. These values revealed that PVP/PVA blends are miscible at all compositions both at 30°C and 50°C. In addition, Fourier transform infrared studies and scanning electron microscope analysis were the supporting evidence for miscibility of this system. In addition, adiabatic compressibility (βad), acoustical impedance (Z) and intermolecular free length (Lf) were also computed.