Characterization of chitosan/montmorillonite hybrid filled tapioca starch nanocomposite films

摘要

Biodegradable nanocomposite films from chitosan/montmorillonite (MMT) hybrid filled plasticized tapioca starch (TPS) were developed using a solution casting method. Chitosan was extracted from local shrimp shell resources with the degree of deacetylation of 60.85%. X-ray diffraction (XRD) analysis showed that the interlayer spacing of the chitosan/MMT/TPS nanocomposite films was slightly increased, indicated that the chitosan molecules were too large to intercalate into clay galleries. However, scanning electron microscopy (SEM) analysis found that the chitosan/MMT/TPS nanocomposite films producing more homogeneous distribution of MMT nanoclay particulate compared to the MMT/TPS nanocomposite films. Fourier transform infrared (FTIR) analysis showed that the shifting in amino group peak of chitosan indicated that the physical interaction occurred between hydroxyl groups (OH) of MMT and amino groups (NH2) of chitosan. In addition, the broad stretch of OH was also shifted to lower wavelength number proven that hydrogen bonding was formed among starch, MMT and chitosan. It was found that the tensile properties improved in flexibility with moderate strength upon addition of chitosan in MMT/TPS nanocomposite films while the thermal stabilities improved upon addition of MMT in starch films but decreased with the addition of chitosan. The water vapor transmission rate of MMT/TPS films decreased after adding chitosan and the condition was the same for water absorption of the films. The light absorbance was also lowered upon addition of chitosan. Overall, addition of MMT and chitosan improved the TPS film properties that intended for packaging application purposes