为了研究添加抗菌剂后，聚乳酸复合膜的抗菌性能，选取了壳聚糖、茶多酚、MgO和银四种抗菌剂，与聚乳酸形成四种复合膜，对比了不同抗菌剂的效果，并利用红外光谱仪对复合膜的结构进行了表征。实验发现，无论哪种抗菌剂，均表现了良好的抗菌效果。当壳聚糖/聚乳酸、茶多酚/聚乳酸均按质量比5:5组成复合膜时，抗菌率分别为68.54%和70.26%，当MgO的添加量为2%时，抗菌率为71.01%，而银表现出了极强的抗菌效果，添加量为1%时，抗菌率达到了98.53%。透光率随着抗菌剂的加入都有不同程度的减小，其中茶多酚的影响最大，从88.67%下降到33.75%。薄膜DSC曲线显示，未添加抗菌剂时，薄膜Tm为80.3 ℃，添加Ag和MgO后，薄膜Tm分别下降了1.7 ℃和1.4 ℃，说明抗菌剂的添加对薄膜Tm几乎无影响。由此可以看出，天然抗菌剂的抗菌效果要略差于无机抗菌剂。

In order to study the antibacterial properties of polylactic acid composite film after adding antibacterial agent, four antibacterial agents, chitosan, tea polyphenol, MgO and silver, were selected to form four composite films with polylactic acid and the effects of different antibacterial agents were compared. The structures of the composite films were characterized by FTIR. The experiment found that no matter which kind of antibacterial agent, it showed good antibacterial effect. When chitosan/polylactic acid and tea polyphenol/polylactic acid were combined into a composite film at a mass ratio of 5:5, the antibacterial percentages were 68.54% and 70.26%,respectively. When the amount of MgO added was 2%, the antibacterial percentage was 71.01%, while silver showed a strong antibacterial effect, the antibacterial percentage reached 98.53% when the amount was 1%. The light transmittance decreased to varying degrees with the addition of antibacterial agents, among which tea polyphenols had the greatest influence, from 88.67% to 33.75%. The DSC curve of the film showed that the films’ Tm was 80.3 ℃ with no antibacterial agent added. After adding Ag and MgO, the films’ Tm decreased by 1.7 ℃ and 1.4 ℃, respectively. This showed that the addition of antibacterial agents had almost no effect on the film Tm. It can be seen that the antibacterial effect of the natural antibacterial agent is slightly worse than the inorganic antibacterial agent.

国家自然科学青年基金项目（31601529）；国家重点研发计划项目（2017YFB0305400）；四川省科技计划项目（2018NZ0150；2019YJ0660）；成都市科技局重点研发（2018-YF05-01185-SN）