title: Dissolution of unmodified waxy starch in ionic liquid and solution rheological properties.
abstract: Dissolution of waxy corn starch in 1-ethyl-3-methylimidazolium acetate (EMIMAc) was qualitatively studied and compared with gelatinisation process in water. The rheological properties of starch-EMIMAc solutions were investigated in dilute and semi-dilute regions, from 0.1 to 10 wt% over temperature range from 20 °C to 100 °C. The values of zero shear viscosity were obtained by applying Carreau-Yasuda model to shear-thinning flow curves and plotted vs. polymer concentration. Power law exponents in viscosity-concentration dependence in semi-dilute region were compared with the ones reported previously for microcrystalline cellulose. Intrinsic viscosity was obtained as a function of temperature and compared with the one of microcrystalline cellulose; starch was found to be much less temperature sensitive than cellulose. Amylopectin overlap concentration in EMIMAc was compared with the one in water and 0.5 M NaOH-water. Based on these comparisons it was suggested that starch conformation in EMIMAc is similar to the one in water (compact ellipsoid). The activation energy was calculated for starch-EMIMAc solutions and demonstrated to obey power-law concentration dependence.
authors: Centre de Mise en Forme des Matériaux - CEMEF, Mines ParisTech, UMR CNRS 7635, BP 207, 06904 Sophia-Antipolis, France.
authors: Weiqing
authors: W
authors: Liu
authors: Tatiana
authors: T
authors: Budtova
mesh_terms: D005782:Gels / Q000737:chemistry; D057446:Hydrodynamics; D007093:Imidazoles / Q000737:chemistry; D052578:Ionic Liquids / Q000737:chemistry*; D012212:Rheology / Q000379:methods; D012972:Sodium Hydroxide / Q000737:chemistry; D012996:Solutions / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D013213:Starch / Q000737:chemistry*; D013696:Temperature; D014783:Viscosity; D014867:Water / Q000737:chemistry; D014885:Waxes / Q000737:chemistry*; D003313:Zea mays / Q000737:chemistry
chemical_list: D005782:Gels; D007093:Imidazoles; D052578:Ionic Liquids; D012996:Solutions; D012997:Solvents; D014885:Waxes; D014867:Water; D012972:Sodium Hydroxide; D013213:Starch; C518739:1-ethyl-3-methylimidazolium