Effect of Type and Content of Modified Montmorillonite on the Structure and Properties of Bio-Nanocomposite Films Based on Soy Protein Isolate and Montmorillonite |
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Authors: | P Kumar KP Sandeep S Alavi VD Truong RE Gorga |
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Affiliation: | Authors Kumar and Sandeep are with Dept. of Food, Bioprocessing, and Nutrition Sciences and author Gorga is with Dept. of Textile Engineering, Chemistry and Science, North Carolina State Univ., Raleigh, NC 27695, U.S.A. Author Alavi is with Dept. of Grain Science and Industry, Kansas State Univ., Manhattan, KS 66506, U.S.A. Author Truong is with U.S. Dept. of Agriculture, Agricultural Research Service, South Atlantic Area, Food Science Research Unit, Raleigh, NC 27695, U.S.A. Direct inquiries to author Sandeep (E-mail: kp_sandeep@ncsu.edu). |
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Abstract: | Abstract: The nonbiodegradable and nonrenewable nature of plastic packaging has led to a renewed interest in packaging materials based on bio-nanocomposites (biopolymer matrix reinforced with nanoparticles such as layered silicates). Bio-nanocomposite films based on soy protein isolate (SPI) and modified montmorillonite (MMT) were prepared using melt extrusion. The effect of different type (Cloisite 20A and Cloisite 30B) and content (0% to 15%) of modified MMT on the structure (degree of intercalation and exfoliation) and properties (color, mechanical, dynamic mechanical, thermal stability, and water vapor permeability) of SPI-MMT bio-nanocomposite films were investigated. Extrusion of SPI and modified MMTs resulted in bio-nanocomposites with exfoliated structures at lower MMT content (5%). At higher MMT content (15%), the structure of bio-nanocomposites ranged from intercalated for Cloisite 20A to disordered intercalated for Cloisite 30B. At an MMT content of 5%, bio-nanocomposite films based on modified MMTs (Cloisite 20A and Cloisite 30B) had better mechanical (tensile strength and percent elongation at break), dynamic mechanical (glass transition temperature and storage modulus), and water barrier properties as compared to those based on natural MMT (Cloisite Na+). Bio-nanocomposite films based on 10% Cloisite 30B had mechanical properties comparable to those of some of the plastics that are currently used in food packaging applications. However, much higher WVP values of these films as compared to those of existing plastics might limit the application of these films to packaging of high moisture foods such as fresh fruits and vegetables. |
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Keywords: | bio-nanocomposite films modified montmorillonite properties soy protein isolate structural characterization |
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