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Lookup NU author(s): Professor David XieORCiD
This is the authors' accepted manuscript of an article that has been published in its final definitive form by Elsevier, 2016.
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The focus of this study was on the effects of plasticisers (the ionic liquid 1-ethyl-3-methylimidazolium acetate, or [Emim][OAc]; and glycerol) on the changes of starch structure on multiple length scales, and the variation in properties of plasticised starch-based films, during ageing. The films were prepared by a simple melt compression moulding process, followed by storage at different relative humidity (RH) environments. Compared with glycerol, [Emim][OAc] could result in greater homogeneity in [Emim][OAc]-plasticised starch-based films (no gel-like aggregates and less molecular order (crystallites) on the nano-scale). Besides, much weaker starch–starch interactions but stronger starch-[Emim][OAc] interactions at the molecular level led to reduced strength and stiffness but increased flexibility of the films. More importantly, [Emim][OAc] (especially at high content) was revealed to more effectively maintain the plasticised state during ageing than glycerol: the densification (especially in the amorphous regions) was suppressed; and the structural characteristics especially on the nano-scale were stabilised (especially at a high RH), presumably due to the suppressed starch molecular interactions by [Emim][OAc] as confirmed by Raman spectroscopy. Such behaviour contributed to stabilised mechanical properties. Nonetheless, the crystallinity and thermal stability of starch-based films with both plasticisers were much less affected by ageing and moisture uptake during storage (42 days), but mostly depended on the plasticiser type and content. As starch is a typical semi-crystalline bio-polymer containing abundant hydroxyl groups and strong hydrogen bonding, the findings here could also be significant in creating materials from other similar biopolymers with tailored sensitivity and properties to the environment.
Author(s): Zhang B, Xie F, Zhang T, Chen L, Li X, Truss RW, Halley PJ, Shamshina JL, McNally T, Rogers RD
Publication type: Article
Publication status: Published
Journal: Carbohydrate Polymers
Year: 2016
Volume: 146
Pages: 67-79
Print publication date: 01/08/2016
Online publication date: 22/03/2016
Acceptance date: 19/03/2016
Date deposited: 10/10/2023
ISSN (print): 0144-8617
ISSN (electronic): 1879-1344
Publisher: Elsevier
URL: https://doi.org/10.1016/j.carbpol.2016.03.056
DOI: 10.1016/j.carbpol.2016.03.056
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