A degradable flocculant was prepared by natural renewable products (starch) and a cationic polymer. A cationic polyamine polymer was prepared by reaction of bis(hexamethylene)triamine with epichlorohydrin. The influence of substrate ratio and molecular weight of cationic polymer on flocculation was investigated and the optimum molecular weight was about 4000. Polyamine-modified starch flocculant was prepared by etherification reaction of cationic polyamine polymer and corn starch. The influence of substitution degree (DS) of starch on flocculation was investigated and the maximum DS was 0.18. The structure of starch-modified flocculant was characterized by XRD and the results confirmed that the plasticized samples contained some crystalline structures that were not destroyed by the etherification reaction process and some newly formed V-type crystalline structures were mainly induced by processing. Flocculation performance was evaluated in simulated kaolin suspension and was compared with that of commercial cationic polyacrylamide (CPAM) and polyaluminium chloride (PAC) flocculants. The flocculation effects of polyamine-modified starch flocculants and commercial flocculants under different dosages and pH values were compared. The results showed that the starch-modified flocculant had the best effect and the cationic starch derivatives flocculation performance increased with increasing DS, and exhibited steady flocculation performance to kaolin suspension in the broad pH range from 4 to 10. The preparation method of starch-modified flocculant is simple in preparation process, low in production cost and pollution-free, and facilitates industrial production.

通过天然可再生产品（淀粉）和阳离子聚合物制备可降解的絮凝剂。通过双（六亚甲基）三胺与表氯醇反应制备阳离子多胺聚合物。研究了底物比例和阳离子聚合物分子量对絮凝的影响，最佳分子量约为4000。通过阳离子多胺聚合物与玉米淀粉的醚化反应制备了多胺改性淀粉絮凝剂。研究了淀粉的取代度（DS）对絮凝的影响，最大DS为0.18。用XRD对淀粉改性絮凝剂的结构进行了表征，结果证实增塑样品含有一些未被醚化反应破坏的晶体结构，且一些新形成的V型晶体结构主要是通过加工诱导的。在模拟的高岭土悬浮液中评估了絮凝性能，并将其与商业阳离子聚丙烯酰胺（CPAM）和聚氯化铝（PAC）絮凝剂进行了比较。比较了多胺改性淀粉絮凝剂和市售絮凝剂在不同剂量和pH值下的絮凝效果。结果表明，淀粉改性絮凝剂效果最好，阳离子淀粉衍生物的絮凝性能随DS的增加而增加，