Effect of poly(vinyl pyrrolidone) on the morphology and physical properties of poly(vinyl alcohol)/sodium montmorillonite nanocomposite films

Nanocomposites of poly(vinyl alcohol) (PVA), poly(vinyl pyrrolidone) (PVP) and sodium monunorillonite (Na+MMT) were prepared by solution mixing and then cast into films. X-ray diffraction analysis and images of transmission electron microscopy establish the formation of PVA/Na+MMT intercalated nanocomposite. Exfoliated and highly intercalated PVA/PVP/Na+MMT nanocomposite formed in the presence of PVP. Inclusion of PVP in PVA/Na+MMT matrix enhances the hydrogen bonding interactions between PVA and Na+MMT and thus increases the mechanical properties and thermal stability of PVA/PVP/Na+MMT nanocomposites compared to PVA/Na+MMT nanocomposite. The interactions between PVA, PVP and NI(CMMT were established by the Fourier transform infrared spectroscopy. The moisture absorption tendency of both the PVA and PVA/PVP films reduced after the incorporation of Na+MMT at 75% constant relative humidity. Differential scanning calorimetry studies show that the presence of PVP and Na+MMT both are responsible for reducing the heat of fusion, and crystallinity of PVA. The flow behavior of the PVA, PVA/PVP and its nanocomposite solutions has been also studied. Water vapor permeability of PVA/PVP/Na+MMT composite films decreased in the presence of nanoclay due to increasing tortuous paths for diffusion. (C) 2013 Chinese Materials Research Society. Production and hosting by Elsevier B.V. All rights reserve