Extruded foams prepared from high amylose starch with sodium stearate to form amylose inclusion complexes*

Abstract

Extruded starch foams were prepared from high amylose corn starch with and without sodium stearate and poly(vinyl alcohol) (PVOH) to determine how the formation of amylose-sodium stearate inclusion complexes and PVOH addition would affect foam properties. X-ray diffraction and Differential Scanning Calorimetry (DSC) showed that amylose-sodium stearate inclusion complexes were formed by low temperature extrusion and did not dissociate during foam formation by a second extrusion at higher temperatures. In the absence of PVOH, water absorption, and foam shrinkage at 95% RH were decreased because of the hydrophobicity of the complex. PVOH addition increased both the expansion ratio and the shrinkage of the foam, although shrinkage at 95% RH was still less than that observed with uncomplexed amylose. The structural integrity and some tensile properties of stearatecontaining foams were improved by PVOH addition. These results provide the manufacturer of biodegradable starch foams with an inexpensive method for tailoring foam properties for specific end-use applications. V C 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43251.

Starch-Based Foams Nucleated and Reinforced by Polysaccharide-Based Crystals

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Foamed bioplastics: a review

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