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Lookup NU author(s): Professor David XieORCiD
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND).
The effects of molecular and crystalline structures on the tensile mechanical properties of thermoplastic starch (TPS) films from waxy, normal, and high-amylose maize were investigated. Starch structural variations were obtained through extrusion and hydrothermal treatment (HTT). The molecular and crystalline structures were characterized using size-exclusion chromatography and X-ray diffractometry, respectively. TPS from high-amylose maize showed higher elongation at break and tensile strength than those from normal maize and waxy maize starches when processed with 40% plasticizer. Within the same amylose content, the mechanical properties were not affected by amylopectin molecular size or the crystallinity of TPS prior to HTT. This lack of correlation between the molecular size, crystallinity and mechanical properties may be due to the dominant effect of the plasticizer on the mechanical properties. Further crystallization of normal maize TPS by HTT increased the tensile strength and Young's modulus, while decreasing the elongation at break. The results suggest that the crystallinity from the remaining ungelatinized starch granules has less significant effect on the mechanical properties than that resulting from starch recrystallization, possibly due to a stronger network from leached-out amylose surrounding the remaining starch granules.
Author(s): Li M, Xie F, Hasjim J, Witt T, Halley PJ, Gilbert RG
Publication type: Article
Publication status: Published
Journal: Carbohydrate Polymers
Year: 2015
Volume: 117
Pages: 262-270
Print publication date: 06/03/2015
Online publication date: 02/10/2014
Acceptance date: 02/09/2014
Date deposited: 10/10/2023
ISSN (print): 0144-8617
ISSN (electronic): 1879-1344
Publisher: Elsevier
URL: https://doi.org/10.1016/j.carbpol.2014.09.036
DOI: 10.1016/j.carbpol.2014.09.036
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