Designing kaolin-reinforced bionanocomposites of poly(vinyl alcohol)/gelatin and study of their mechanical and water vapor transmission behavior

In the present work, gelatin/PVA–kaolin nanocomposites were prepared by dispersing kaolin into a host matrix of gelatin/PVA to cause exfoliation of the added clay. The DSC, FTIR, AFM and XRD techniques were used to characterize the prepared bionanocomposite materials. The crystalline nature and the three-dimensional surface topology at nano-scales of the bionanocomposite films were confirmed by the XRD and AFM analysis, respectively. The morphological insights of synthesized materials were obtained by scanning electron microscopy which suggested for a compact and homogenous surface architecture. The FTIR spectral results indicated that the kaolin was exfoliated within the host matrix of gelatin–PVA. Swelling nature and water vapor transmission studies were conducted, and the results obtained suggested that the swelling ratio and water vapor transmission rate of bionanocomposite decreased with increasing amount of the kaolin content. The tensile strength measurements of the bionanocomposite film provided information about the mechanical behavior of the material. The prepared bionanocomposite films were also studied for their microhardness property. Mechanical and barrier properties were found to increase with the addition of kaolin thus indicating the suitability of the as-prepared material for applications in food packaging.