Liu Haihui

Ionically Conducting Polymers Based on Ionic Liquid-Plasticized Starch Containing Lithium Chloride

Ionic liquids (ILs) comprising 1-allyl-3-methylimidazolium chloride ([amim]Cl) with certain concentrations of lithium chloride (LiCl), have been used to prepare cast samples of ionically-conducting thermoplastic starch (TPS), with potential applications as solid biopolymer electrolytes. Atomic force microscopy (AFM) found that the diameter of residual starch granules existing in [amim]Cl and glycerol-plasticized starch films was about 10 nm. An increased concentration of LiCl tended to decrease the proportion of residual starch granules and form homogeneous TPS. LiCl also increased the interaction of [amim]Cl with plasticized starch, as detected by Fourier Transform infrared (FT-IR) spectroscopy and dynamic mechanical thermal analysis (DMTA). Thermogravimetric analysis (TGA) indicated that the supramolecular structure of starch was destroyed by [amim]Cl and LiCl. LiCl not only increased the water absorption of TPS, but also improved its electrical conductivity; the latter achieved values as high as 101.0 S cm-1 at 20 wt.% water absorption.

A Facile Method for Preparation of Thermoplastic Starch/Urea Modified Montmorillonite Nanocomposites

A facile two-step melt extrusion processing method was used to prepare high performance thermoplastic starch (TPS)/urea modified montmorillonite (UMMT) nanocomposites in this work. X-ray diffraction (XRD) and transmission electron microscope (TEM) demonstrated that urea could destruct the multilayer and platelet structure of montmorillonite during the first melt extrusion processing, which was propitious to form intercalated or exfoliated nanocomposites in the second melt extrusion processing. UMMT, starch, and 30 wt% plasticizers (formamide and urea (1 : 2 wt%)) based on the starch could form partially exfoliated nanocomposites proved by XRD and TEM, respectively. Fourier transform infrared proved intense interactions existed in UMMT and TPS/UMMT nanocomposites. So high UMMT content could obviously increase the thermal stability and mechanical properties of nanocomposites, especially the tensile strength, Young’s modulus, and energy break could reach to 17.8 MPa, 210 MPa, and 760 J/m 3, respectively. Finally, the increasing montmorillonite contents also decreased the water absorption and water vapor permeability of TPS material.