Plasticized Starch Based Bionanocomposites Containing Cellulose Nanowhiskers and Titanium Dioxide Nanoparticles: Study of Structure and Water Vapor Permeability

The starch-based films have some disadvantages such as weak mechanical and poor water barrier properties that restrict their applications in food packaging. In the present research، to improve the properties of the starch films، a constant level of citric acid and polyvinyl alcohol (PVA) (10%) with different amounts of glycerol (GLY) as a lubricating agent، crystal nanowhiskers (CNW) and titanium dioxide (TiO2) nanoparticles were used together. Finally، the effects of these compounds on permeability properties of the obtained starch-based bionanocomposites were studied and their optimum values were determined by central composite design of response surface methodology (RSM). The results of X-Ray diffraction (XRD) test showed that at low levels of TiO2 and CNW there was no diffractogram peak obtained. However، at high levels of TiO2 and CNW there emerged distinct and sharp peak which was attributed to greater crystalline region and probably non-homogeneity in particle distribution. The Fourier transmission infrared (FTIR) data showed that addition of CNW and TiO2 increased hydrogen binding between the nanofillers and biopolymer matrix. The effects of TiO2 and CNW concentrations as quadratic and glycerol concentration as linear and quadratic were significant on water vapor permeability (WVP). The optimum levels of TiO2، CNW and GLY for obtaining minimum WVP corresponded to 0. 118، 0. 3 g and 1. 06 mL، respectively.