中文摘要：

通过γ-氯丙基三甲氧基硅烷的偶联，将水溶性聚乙烯亚胺（PEI）接枝在纳米SiO2表面，随后分别用1-溴己烷和碘甲烷对接枝的PEI进行N-烷基化修饰，使PEI中的部分氨基转变成季铵盐，得到水不溶性QPEI／SiO2微粒。通过测定PEI／SiO2上PEI的接枝量，考察了各种反应条件对QPEI／SiO2微粒制备的影响规律。研究结果表明，纳米SiO2表面接枝PEI的适宜条件为：反应溶剂为DMF，反应温度90-100℃，反应时间8h，氯丙基化SiO2与PEI质量比为4：1，在此条件下制备的QPEI／SiO2微粒中PEI接枝量为14．8％。QPEI／SiO2微粒经甲基化修饰后，季铵盐含量由0．96％增加到3．37％，其抗菌性能显著增强。

英文摘要：

Water-soluble polyethylenimine （PEI） was grafted onto the surface of nano-SiO2 particles through the couple effect of γ-chloropropyltrimethoxysilane, and the water-insoluble antimicrobial SiO2 particles grafted with quaternized polyethylenimines （ QPEI/SiO2 ） was prepared followed by the N-alkylation of coated PEI with 1-bromohexane and idomethane ,respectively. The influences of various factors on the preparation of QPEI/SiO2 were examined via measuring the grafted amount of PEI on the composite of QPEI/SiO2. The results show that the optimum reaction conditions are as follows：the reaction temperature is 90 - 100 ℃ ,the reaction time is 8 h ,the mass ratio of CP-SiO2 to PEI is 4 ： 1 ,and the reaction solvent is dimethyl formamide （DMF）. The grafted amount of PEI in the QPEI/SiO2 prepared at the above conditions is 14.8%. Compared to the QPEI/SiO2 without methylation, the amount of quaternary ammonium salts in the methylated QPEI/SiO2 was added from 0.96% to 3.37%, and its antimicrobial activities against bacteria and yeast were enhanced obviously.