Preparation of Starch Nanoparticles in a New Ionic Liquid-in-Oil Microemulsion

Abstract

In this work, a new room-temperature ionic liquid 1-hydroxypropyl-3-methylimidazolium acetate ([C3OHmim]Ac) was synthesized to dissolve starch and substitute for polar phase to form [C3OHmim]Ac/TX-100+1-butanol/cyclohexane microemulsions. The molecular structure of [C3OHmim]Ac was confirmed by means of 1H nuclear magnetic resonance (1HNMR) and electrospray ionization masss pectrometry (ESI–MS). Pseudo-ternary phase diagram, conductivity measurement and dynamic light scattering (DLS) were used to analyze the microregion of IL/O micro-emulsion. Starch nanoparticles were prepared in this novel IL/O micro-emulsion with octenyl succinic anhydride (OSA) maize starch as the raw material and epichlorohydrin as the cross-linker. Fourier transform infrared spectroscopy (FTIR) data demonstrated the formation of crosslinking bonds in starch molecules. The spectrum of XRD suggested that the crystal structure of starch was destroyed. Scanning electron microscopy (SEM) and dynamic light scattering (DLS) both intuitively revealed that starch nanoparticles had good sphericity, small size and a relatively concentrated size distribution with the mean diameter of starch nanoparticles 105 nm.