By reactive extrusion, glycidyl methacrylate (GMA), starch and polyhexamethylene guanidine hydrochloride (PHMG) were simultaneously ring-opening reaction, and then polymerize to form a micro-crosslinked structure. The effects of crosslinking degree on hydrophilicity, mechanical properties, thermal stability and antibacterial activity were studied. According to the results, with the increase of GMA content, the degree of crosslinking was significantly risen, leading to improved hydrophobicity of starch and a high coupling efficiency (CE) (88.3 %) of PHMG. The micro-crosslinking effect also raises the thermal decomposition temperature of starch from 209 ℃ to 239 ℃, enhancing thermal stability. It is worth noting that the micro-crosslinked structure formed by appropriate amount of GMA(≤2 wt%) can increase the tensile strength of the modified starch film, reaching 6.28 MPa at 2 wt% GMA. Due to the high CE of PHMG, the modified antibacterial starch film still showed excellent antibacterial activity against E. coli and S. aureus after 7 days, and had significant long-lasting antibacterial effect, which represented potential value in the application of food packaging.

通过反应挤出，甲基丙烯酸缩水甘油酯（GMA）、淀粉和聚六亚甲基胍盐酸盐（PHMG）同时发生开环反应，然后聚合形成微交联结构。研究了交联度对亲水性、力学性能、热稳定性和抗菌活性的影响。结果表明，随着GMA含量的增加，交联度显着升高，导致淀粉的疏水性改善和PHMG的高偶联效率（CE）（88.3%）。微交联效应还将淀粉的热分解温度从209℃提高到239℃，增强了热稳定性。值得注意的是，适量的GMA（≤2 wt%）形成的微交联结构可以提高变性淀粉膜的拉伸强度，在2 wt% GMA时达到6.28 MPa。由于PHMG的CE较高，改性抗菌淀粉膜在7天后仍对大肠杆菌和金黄色葡萄球菌表现出优异的抗菌活性，并且具有显着的长效抗菌效果，在食品包装中具有潜在的应用价值。