Effect of poloxamer on the solubility coefficient of water and the enthalpy recovery of cast poly(vinylpyrrolidone) films

The objective of this work was to study the influence of a poloxamer (Lutrol® F127) on the solubility coefficient of water and the enthalpy recovery measured at the glass transition temperature of cast poly(vinylpyrrolidone) (PVP) films as a function of storage time and relative humidity. The PVP films were stored under different relative humidity conditions at room temperature during three storage periods. After storage, the solubility coefficient of water and the enthalpy recovery values of the films were determined. Along with the increase of the solubility coefficient of water for PVP, the enthalpy recovery measured at the glass transition temperature was also increased. The presence of poloxamer in the cast PVP films inhibited the anomalous glassy-to-rubbery transition and decreased the enthalpy recovery of the rubbery PVP, thus it could have a protective effect against the negative influence of water vapour on the physical ageing of PVP films.