Studies of miscibility behavior and hydrogen bonding in blends of poly(vinylphenol) and poly(vinylpyrrolidone)

Polymer blends of poly(vinylphenol) (PVPh) with poly(vinylpyrrolidone) (PVP) were prepared by solution casting from the N,N-dimethylformamide (DMF) solution. Differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), and solid-state nuclear magnetic resonance (NMR) were used to investigate the hydrogen bonding and miscibility behavior of the blend. This PVPh/PVP blend system has a single glass transition temperature over the entire composition range, indicating that this blend is able to form a miscible phase due to the formation of inter-hydrogen bonding between the hydroxyl of PVPh and the carbonyl of PVP. Furthermore, FTIR and solid-state NMR were used to study the hydrogen-bonding interaction between the PVPh hydroxyl group and the PVP carbonyl group at various compositions. According to the Painter-Coleman association model (PCAM), the interassociation constant for the PVPh/PVP blend is significantly higher than the self-association constant of PVPh, revealing that the tendency toward hydrogen bonding of the PVPh and PVP dominates the intra-hydrogen bonding of the PVPh in the mixture.