中文摘要：

采用两步法合成N,N,N-三甲基壳聚糖季铵盐,再用己酰氯改性,得到N,N,N-三甲基-O-己酰化壳聚糖季铵盐（TMHC）。产物用1 H NMR、FT-IR和EA等进行表征。抗菌实验结果表明,酰化改性能有效提高壳聚糖季铵盐的抗菌活性,并且随着酰化度的提高抗菌活性增加;TMHC对革兰氏阳性菌S.au-reus的抗菌活性比革兰氏阴性菌E.coli强;另外,相同浓度（50mmol/L）金属离子对TMHC抗菌活性的抑制作用按以下顺序递减：Ba2＋〉Ca2＋〉Mg2＋,而同一金属离子（Mg2＋）对TMHC抗菌活性的抑制作用则随着离子浓度的增加而增加。

英文摘要：

O-methyl free N,N,N-trimethyl chitosan（TMC） was synthesized through two steps,then TMC and hexanoyl chloride were used to prepare N,N,N-trimethyl-O-hexanoyl-chitosan（TMHC）.The products were characterized by 1H NMR,FT-IR and EA.The results of antimicrobial test indicated that the antibacterial activity of TMHC was stronger than TMC by acylation modification,and increased with the degree of substitution increased.TMHC showed stronger antibacterial activity against S.aureus than against E.coli.In addition,the same concentration（50mmol/L） of divalent cations reduced the antibacterial activity of TMHC in the following order：Ba2＋ Ca2＋Mg2＋.And the antibacterial activity inhibition of TMHC at the same metal ion（Mg2＋） condition reduced with the increasing ion concentration.