Effects of temperature and solvent composition on the intrinsic viscosity of polyvinyl butyral in ethanol/water solutions

In this work, the samples of polyvinyl butyral (PVB) with an average degree of acetalization of 79.56% and the average molecular weight of 68.696 kg·mol −1 were prepared by polyvinyl alcohol (PVA) and n-butyraldehyde, catalyzed by p-Toluenesulfonic acid (PTSA). The intrinsic viscosities of PVB were measured in ethanol/water solutions in the temperature range of 293.15–313.15 K. The expansion factors of PVB molecular chains were calculated with the intrinsic viscosity data. The related thermodynamic parameters were derived from the temperature dependence of expansion factors and results indicate that the quality of mixed ethanol/water solvents for PVB solutions decreases with the increase of temperature and the volume fractions of water.