Oxidized Starch Modification And Er Performance

Starch is a cheap, natural, renewable resource. It is an ideal"Green"material, presenting excellent biodegradability and regenerability. The basic molecular structure of starch is anhydroglulose unit, and the carbon of 2, 3, 6 bits of every anhydroglulose unit has a bioactive hydroxyl group. Therefore, chemical modification, such as oxidation, esterification, etherification, cross linking, and graft copolymerization of hydroxyl group can be carried out on starch to change its reactive properties.Oxidized starch is synthesized by starch and oxidant under acide, alkali or neutral medium. After oxidation, the amount of hydroxyl decreases, the assciation of molecules is blocked off, and the binding level of hydrogen bonds amoung molecules reduces. Meanwhile, polymerization degree of starch reduces, while the water- solubility, felt force and stability increase.The starch graft copolymer, one of the active research fields in starch modification, is a kind of copolymer bonded natural polymer and synthesized polymer. It shows excellent properties both of these two polymers, extending the application range of natural polymer.In this paper, starch was used as raw material. Firstly, optimal condition of synthesis oxidized starch was ascertained, and then the modified starch composite was prepared by oxidized starch from graft copolymerization. Finally, rare earth element was introduced into starch graft copolymer. The polarization ability was improved, and electrorheological fluid with biodegradability was synthesized.1. Synthesis and characterization of oxidized starchOxidized starch was synthesized by using H₂O₂ as oxidant, and FeSO₄ as catalyst. Oxidized starch was characterized by IR, XRD and SEM. The content of carboxyl group was tested by hot paste titration, and the content of carbonyl group was decided by hydroxylamine method. The dosage of H₂O₂ and pH value of solution was discussed...