Oxidized starch films reinforced with natural halloysite

Oxidized starch (OSt) films reinforced with natural halloysite were prepared by adding modified natural halloysite nanotubes into an OSt matrix. The halloysite/OSt films were characterized by x-ray diffraction, scanning electron microscopy, and ultraviolet spectrometry. The mechanical properties and moisture absorbability of the films were also studied. The modified halloysite nanotubes were well distributed in the starch matrix, and the tensile strength (TS) of the films was greatly enhanced, but the moisture adsorption ability of the films only changed slightly. The flexibility of the films was improved by adding glycerol but at a cost of reducing the TS. Incorporating a small amount of poly(vinyl alcohol) (PVA) improved both the TS and the percent elongation at break of the halloysite/OSt films.