Compatibility studies of chitosan/PVA blend in 2% aqueous acetic acid solution at 30 °C

The miscibility of chitosan (CS) and poly(vinyl alcohol) (PVA) blends in aqueous acetic acid solution was studied using viscosity, ultrasonic velocity and refractive index techniques at 30 °C. From the viscosity data by using Sun and Chee et al., approaches, the interaction parameters ΔB, μ and α   are also calculated to predict the blend compatibility of the blend solutions. The results of these blends data suggest that CS/PVA blends were completely miscible in all proportions. The results pertaining to variation of ultrasonic velocity (vv) and their derived parameters such as adiabatic compressibility, acoustic impedance, relaxation strength and Rao number also supports the miscibility nature of these blends. This is further confirmed by refractive index results also. Differential scanning calorimetry (DSC), XRD and FT-IR were also used to confirm the compatibility of the CS/PVA blends in the solid state (thin films). Experimental results showed that the blends of CS and PVA are miscible at all the compositions due to the strong intermolecular hydrogen bonding interactions between CS and PVA.