Miscibility studies of HPMC/PVA blends in water by viscosity, density, refractive index and ultrasonic velocity method

Hydroxy propyl methyl cellulose (HPMC)/polyvinyl alcohol (PVA) blends are edible polymer films used for food packing and directly in foodstuffs. However they are water-soluble in ordinary temperature and have good mechanical properties. The miscibility of HPMC/PVA blend in water was studied by viscosity, ultrasonic velocity, density and refractive index techniques at 30 and 50 °C. Using viscosity data, the interaction parameters μ and α were calculated. These values revealed that HPMC/PVA blend is miscible when the HPMC content is more than 60% in the blend at 30 and 50 °C. And also the result revealed that the change in temperature has no significant effect on the miscibility of HPMC/PVA polymer blend.