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In this work, corn starch films were crosslinked with a novel bio-based agent; oxidized sucrose and their strength and stability were improved. Although starch is an inexpensive, biodegradable and abundant source, industrial applications of starch films are limited due to their poor mechanical properties. Crosslinking is one of the most common methods to enhance the mechanical properties of starch films. However, most of the available crosslinkers, such as gluteraldehyde, phosphorus oxychloride, sodium trimetaphosphate, and epichlorohydrin, are either toxic, expensive or with low crosslinking efficiencies. Oxidized sucrose, which is derived by periodate cleavage, has aldehyde groups in the structure and this enables it to be used as a crosslinking agent for starch films. Mechanical properties of crosslinked films and non-crosslinked films, such as tensile strength and elongation, were studied to verify the crosslinking effects of oxidized sucrose. The highest tensile strength obtained in this research is 22.9 MPa with 59.5 % elongation. The chemical and molecular structures of the films were also examined using Fourier Transform Infrared spectroscopy (FTIR), 1H-NMR, 13C-NMR and Differential scanning calorimetry (DSC). The water stability and formic acid stability of starch films were studied. The results show that crosslinking increased the stability of corn starch films both in water and formic acid. Last but not least, kinetic study of bio-crosslinked corn starch films was studied via iodometric titration and crosslinking reaction rate constant, order of reaction and activation energy were calculated.
Adviser: Yiqi Yang