Fenton试剂引发淀粉与顺丁烯二酸共聚羧化淀粉

Graft Copolymerization of Maleic acid onto Starch Initiated by Fenton′s Reagent to Prepare Carboxylic Derivatives of Starch

采用Fenton试剂引发淀粉与顺丁烯二酸进行自由基共聚，在淀粉分子链上引入大量羧基,制备淀粉基聚阴离子。探讨了引发剂浓度、反应温度和反应时间对淀粉羧化程度的影响。实验结果表明，淀粉和顺丁烯二酸质量比为1：1与0.00985mol／L亚铁离子、4．412mol／L H2O2在60℃下反应5h，得到羧基含量为31．32％的羧化淀粉；控制反应温度、反应时间和引发剂浓度,羧化淀粉的羧基含量可在2．7％-31．5％之间进行调节。FTIR分析验证了羧化淀粉的结构：XRD和TGA的分析结果表明，羧化淀粉的结晶度和分解温度（质最分数20％）均随着羧基百分含量的增大而降低。

To prepare starch-based polyanion or to incorporate carboxyl groups onto the backbone of starch,radical copolymerization of starch and maleic acid in an aqueous medium was performed with Fenton＇s reagent as the redox initiator. The effect of reaction conditions such as the initiator concentration, reaction temperature and reaction time on the percent content of carboxyl groups（PCCG） of the derivative was investigated. It was found that the PCCG of the derivative could be 31.32% when 3g starch and 3g maleic acid were initiated by both 0.00985 mol/L Fe^2＋ and 4.412 mol/L H2O2 and copolymerized at 60℃ for 5 h. In addition, PCCG of the derivative could be controlled between 2.7%-31.5% by adjusting the initiator concentration or the reaction temperature. The structure of the derivative was verified by FFIR. X-ray diffraction and TGA results showed that both the crystallinity and 20% -decomposed temperature of the carboxylic derivative decreased with the increase of PCCG.