Preparation and evaluation of hydrophobic biodegradable films made from corn/octenylsuccinated starch incorporated with different concentrations of soybean oil

Corn/octenylsuccinated starch (C/OS) composite films incorporated with soybean oil (SO) at 0, 0.5%, 1.0%, 1.5% and 2.0% (w/w) were prepared to investigate their physicochemical properties. Fourier transform infrared analysis indicated that low concentrations of SO could facilitate molecular interaction and the formation of hydrogen bonds between starch molecules. All the films exhibited similar diffractograms and lower relative crystallinity values. Scanning electron microscopy and atomicforcemicroscopy showed that the irregular and coarse surface structures of the films were obtained more frequently with increasing SO concentration. A higher contact angle of 76.14° and lower water vapor permeability of 2.46 × 10−12 g cm/cm2 s Pa were obtained with increasing SO content, with the exception of the 2.0% SO sample. The highest tensile strength value of 6.54 MPa was obtained by the C/OS-1.0% SO composite film, while the optimumelongation at break of 71.84% was exhibited by the C/OS-1.5% SO composite film.