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United States Department of Agriculture

Agricultural Research Service

Title: Effects of Plastizers on the Structure and Properties of Starch-Clay Nanocomposites

Authors
item Tang, Xiaozhi -
item Alavi, Sajid -
item Herald, Tom

Submitted to: Carbohydrate Polymers
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 7, 2008
Publication Date: April 22, 2008
Citation: Tang, X., Alavi, S., Herald, T.J. 2008. Effects of Plastizers on the Structure and Properties of Starch-Clay Nanocomposites. Carbohydrate Polymers. 74(3):552-558.

Interpretive Summary: Biodegradable nanocomposites were successfully fabricated from corn starch and montmorillonite (MMT) nanoclays by melt extrusion processing. The structure and morphology of the nanocomposites were characterized by X-ray diffraction (XRD) and electron microscopy, and film properties were also measured. As a conventional plasticizer, the influence of glycerol content was first investigated. As the glycerol content decreased from 20% to 5%, the degree of clay exfoliation increased. Films with 5% glycerol exhibited the lowest water vapor permeability, highest glass transition temperature, and highest tensile strength, but low elongation at break. Urea and formamide were tested as alternative plasticizers for the starch-clay nanocomposites. The formamide plasticized starch-clay nanocomposite films exhibited lower water vapor permeability, higher glass transition temperature, and higher tensile strength than the other two plasticizers when used at the same level.

Technical Abstract: Biodegradable nanocomposites were successfully fabricated from corn starch and montmorillonite (MMT) nanoclays by melt extrusion processing. The structure and morphology of the nanocomposites were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM), and film properties such as barrier, mechanical and thermal properties were also measured. As a conventional plasticizer, the influence of glycerol content was first investigated. As the glycerol content decreased from 20% to 5%, the degree of clay exfoliation increased. Films with 5% glycerol exhibited the lowest water vapor permeability (0.41 g mm/kPa h m2), highest glass transition temperature (53.78 °C), and highest tensile strength (35 MPa), but low elongation at break (2.15%). Urea and formamide were tested as alternative plasticizers for the starch–clay nanocomposites. The results indicated that the use of new plasticizers increased the degree of clay exfoliation. The formamide plasticized starch–clay nanocomposite films exhibited lower water vapor permeability (0.58 g mm/kPa h m2), higher glass transition temperature (54.74 °C), and higher tensile strength (26.64 MPa) than the other two plasticizers when used at the same level (15 wt%).

Last Modified: 10/25/2014
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