Development of highly ordered nanofillers in zein nanocomposites for improved tensile and barrier properties.J Agric Food Chem. 2012 Apr 25; 60(16):4162-9.JA
It has been a long-lasting challenge to prepare highly ordered biopolymer nanocomposites to optimize or tune the desired mechanical and barrier properties of the nanocomposite film. In this study, we developed a simple and cost-effective method to synthesize highly ordered zein nanocomposites. The method involved the synthesis of magnetic iron oxide (Fe(3)O(4)) nanofiller and the preparation of a highly ordered structure by in situ nanofiller reorientation under an external magnetic field. The successful preparation of Fe(3)O(4) magnetic nanoplatelets together with exfoliated and highly ordered zein resin nanocomposites was confirmed by scanning electron microscopy, X-ray diffraction, and a vibrating sample magnetometer. As a result, in comparison to zein resin film, the exfoliated zein nanocomposites (Fe-Zein) showed dramatic improvement on mechanical and barrier properties. The tensile strength, elongation, and Young's modulus of Fe-Zein were increased by 218, 48, and 264%, respectively, while the water vapor and oxygen permeability decreased by 68 and 29%. More importantly, the highly ordered zein nanocomposites (Fe-Zein-Mag) showed additional improvement on the mechanical and gas barrier properties. In comparison to Fe-Zein, the tensile strength and elongation of Fe-Zein-Mag were increased by 10 and 48%, respectively, and a 30% decrease in Young's Modulus was observed, indicating the Fe-Zein-Mag film was more elastic. Besides, the water vapor and oxygen permeability of Fe-Zein-Mag were also decreased by an additional 48 and 17%, respectively.