该研究以季铵盐对壳聚糖进行修饰改性，利用单因素实验分析了壳聚糖季铵盐的最优制备条件，通过傅里叶红外光谱、核磁氢谱对其结构进行了表征；并探究不同取代度的壳聚糖季铵盐制备的涂膜的机械性能；以壳聚糖季铵盐为原料，引入聚乙烯醇，纳米二氧化钛，丙三醇，采用溶液共混法制备了壳聚糖季铵盐复合膜，并通过傅里叶红外光谱、热重分析以及接触角对壳聚糖季铵盐复合涂膜的结构、性能进行分析。结果表明，壳聚糖季铵盐的最优制备条件为季铵盐与壳聚糖的质量比为3:1，反应时长为12 h，反应温度为80 ℃。此外，当壳聚糖季铵盐含量为50%（以聚乙烯醇为标准），纳米二氧化钛含量为1%，丙三醇含量为0.8%时，壳聚糖季铵盐复合膜的拉伸强度和断裂伸长率取得最优值，分别为19.38 MPa和55.78%。相应的壳聚糖季铵盐复合膜（19.38 MPa）的拉伸强度较壳聚糖复合膜（18.64 MPa）也高，这说明壳聚糖季铵盐的改性有利于增加涂膜的机械性能，为后续研究壳聚糖改性膜材料提供了一定的理论参考。

In this study, chitosan was modified with quaternary ammonium salt. The optimal preparation conditions of chitosan quaternary ammonium salt were examined by single factor experiments. Its structure was characterized by Fourier infrared spectroscopy and hydrogen nuclear magnetic spectroscopy. The mechanical properties of the coating film prepared by chitosan quaternary ammonium salt with different degrees of substitution were investigated. Using chitosan quaternary ammonium salt as the raw material, with the introduction of polyvinyl alcohol, nano-titanium dioxide, and glycerol, chitosan quaternary ammonium salt-based composite membrane was prepared by the solution blending method. The structure and performance of the composite film of chitosan quaternary ammonium salt were examined by Fourier infrared spectroscopy, thermogravimetric analysis and contact angle measurements. The results revealed the optimal preparation conditions as follows: the mass ratio of quaternary ammonium salt to chitosan was 3:1, reaction time was 12 h, and reaction temperature was 80 ℃. In addition, when the content of chitosan quaternary ammonium salt was 50% (polyvinyl alcohol as the standard), nano-titanium dioxide content was 1%, and glycerol content was 0.8%, optimal tensile strength and elongation at break of chitosan quaternary ammonium salt-based composite membrane were achieved (19.38 MPa and 55.78%, respectively). The tensile strength of the chitosan quaternary ammonium salt-based composite membrane (19.38 MPa) was also higher than that of the chitosan composite membrane (18.64 MPa). This indicated that the modification of chitosan with quaternary ammonium salt was beneficial to the increase of the mechanical properties of the coating, which provides a certain theoretical reference for subsequent studies on membrane materials containing modified chitosan.

广东省基础与应用基础研究基金项目（2019A1515010714）；云南省李普旺专家工作站资助（202005AF150007）；广东省自然科学基金项目（2018A030307015；2018A030313109）；中国热带农业科学院基本科研业务费专项项目（1630122017009；1630122017011；1630062021009）；广东省现代农业产业技术体系创新团队建设专项资金资助（2019KJ140）；湛江市科技项目（2018A02015）