中文摘要：

通过环氧氯丙烷（ECH）对聚乙烯亚胺（PEI）进行改性，制备出具有强阳离子性和反应活性的改性PEI增强剂。研究了改性PEI对纸张的增强作用，并用流变仪、FTIR和SEM对其流变性能、分子结构及纸样微观结构进行了表征。结果表明，改性PEI可使湿抗张指数从3．23N·m／g增加到6．49N·m／g，湿强度保留率从14.3％增加到26．5％，且具有优异的助留性能；产物分子结构中出现了季铵基团；SEM分析表明，纸张断裂是由纤维断裂引起的，为改性PEI可增加纤维间的结合强度提供了依据。

英文摘要：

A kind of paper strengthening agent with strong cation and reactivity was prepared through the modification of polyethylene mine （PEI） with epichlorohydrin （ECH）. The effect of modified PEI on paper strength was studied, and the rheological properties, molecular structure of the modified PEI, and paper microstructure were characterized by rheoviscometer, FTIR and SEM, respectively. The results showed that the modified PEI can increase the wet-tensile index from 3.23 N.m/g to 6.49 N.m/g, and the wet strength of the paper from 14.3%to 26.5%. At the same time, the modified PEI has effective retention aid properties. Quaternary ammonium groups are found in the modified PEI molecular structure. SEM observation showed that paper fracture is caused by fiber breakage, which indicates that the modified PEI can increase interfiber-bonding strength.