Synthesis And Application Of Starch Half Ester Derivatives

Starch Half Ester Derivatives such as starch succinate half ester and starch maleate half ester were obtained by starch and binary anhydride. In this thesis, starch succinate half ester and starch maleate half ester were prepared by dry method and microwave-assisted heating dry method. Higher reaction efficiency and degree of substitution of product were achieved in dry method compared to that in traditional wet method. This provides chances for industrial production and application. Compared with conventional heating synthesis method, microwave-assisted synthesis method under dry medium was a rapid and energy saving one with high reaction efficiency. The structures of starch succinate half ester and starch maleate half ester were characterized by FTIR and NMR spectroscopy. Changes in the starch granules before and after modification were studied by scanning electron microscopy (SEM).Crosslinked starch succinates (CCS) were prepared by a dry reaction. The adsorption behavior of crosslinked starch succinates for Pb (II) was investigated. Physicochemical factors such as equilibrium time, temperature and initial solution pH value affecting magnitude of Pb (II) adsorption were studied. Their adsorption behavior was found to follow langmuir isotherm. The adsorption capacity increased with increasing DS of CCS. The thermodynamic investigation demonstrated that the adsorption process was endothermic. The negative values of △G~θ indicated that the feasibility of adsorption increases.Flocculation of kaolin suspension was investigated using starch maleate half ester as flocculant. The parameters optimized included dose of flocculant, DS of flocculant, viscosity of flocculant, pH value of kaolin suspension temperature in the process. Using starch maleate half ester with DS of 0.07 as flocculant, turbidity of kaolin suspension reduced to 4.2NTU when the dose of flocculant was 4ppm. Turbidity of kaolin suspension was 120NTU when no flocculant was used. Removal ratio of turbidity was 96.3%. It was demonstrated by the experiment that starch maleate half ester with low-cost materials, simple preparation process and good flocculation efficiency is a promising flocculant.Crosslinked cationic starch maleates (CCSM) containing quaternary ammonium cationic groups were prepared by a dry reaction. The adsorption behavior of Crosslinked cationic starch maleates for Cr(VI) was investigated. Physicochemical factors such as equilibrium time, temperature and initial solution pH value affecting magnitude of Cr(VI) adsorption were studied. Their adsorption behavior was found to follow langmuir isotherm. The...