Abstract
Starch-based films plasticised by an ionic liquid, 1-ethyl-3-methylimidazolium acetate ([Emim][OAc]), were prepared by a simple compression moulding process, facilitated by the strong plasticisation effect of [Emim][OAc]. The effects of amylose content of starch (regular vs. high-amylose maize) and relative humidity (RH) during ageing of the samples on a range of structural and material characteristics were investigated. Surprisingly, plasticisation by [Emim][OAc] made the effect of amylose content insignificant, contrary to most previous studies when other plasticisers were used. In other words, [Emim][OAc] changed the underlying mechanism responsible for mechanical properties from the entanglement of starch macromolecules (mainly amylose), which has been reported as a main responsible factor previously. The crystallinity of the plasticised starch samples was low and thus was unlikely to have a major contribution to the material characteristics, although the amylose content impacted on the crystalline structure and the mobility of amorphous parts in the samples to some extent. Therefore, RH conditioning and thus the sample water content was the major factor influencing the mechanical properties, glass transition temperature, and electrical conductivity of the starch films. This suggests the potential application of ionic liquid-plasticised starch materials in areas where the control of properties by environmental RH is desired.
| Original language | English |
|---|---|
| Pages (from-to) | 160-168 |
| Number of pages | 9 |
| Journal | Carbohydrate Polymers |
| Volume | 122 |
| DOIs | |
| Publication status | Published - 20 May 2015 |
Funding
The research leading to these results has received funding from the Australian Research Council (ARC) under the Discovery Project No. 120100344. M. Li also would like to thank the China Scholarship Council (CSC) for providing research funding for her Ph.D. study at The University of Queensland (UQ). The authors acknowledge the facilities, and the scientific and technical assistance, of the Australian Microscopy & Microanalysis Research Facility (AMMRF) at the Centre for Microscopy and Microanalysis (CMM), UQ.
| Funders | Funder number |
|---|---|
| Australian Research Council | 120100344 |
| University of Queensland | |
| China Scholarship Council |
Keywords
- 1-Ethyl-3-methylimidazolium acetate
- Amylose/amylopectin ratio
- Ionic liquid
- Plasticisation
- Relative humidity
- Starch
ASJC Scopus subject areas
- Organic Chemistry
- Polymers and Plastics
- Materials Chemistry