增塑剂对细菌纳米纤维素-壳聚糖复合膜性能的影响

采用浇铸法制备细菌纳米纤维素-壳聚糖复合膜,分析甘油、聚乙二醇、乙酰柠檬酸丁酯3种增塑剂对细菌纳米纤维素-壳聚糖复合膜透光性、水蒸气透过率、力学性能的影响,并应用扫描电镜、傅里叶变换红外光谱仪、X射线衍射仪对复合膜的形貌和结构进行表征。结果表明:细菌纳米纤维素与壳聚糖具有良好的相容性,细菌纳米纤维素-壳聚糖复合膜透明度高,且对紫外光有屏蔽作用;3种增塑剂均可通过削弱细菌纳米纤维素与壳聚糖分子间的氢键、改变复合膜的结晶结构达到增塑效果。3种增塑剂均可降低复合膜的水蒸气透过率,提高复合膜的保湿性能,但其质量分数对该性能影响较小。3种增塑剂均提高了细菌纳米纤维素-壳聚糖复合膜的塑性,增塑效果由强到弱依次为甘油、聚乙二醇、乙酰柠檬酸丁酯。添加质量分数为5%的甘油作为增塑剂时,复合膜具有较优的综合性能,水蒸气透过率为1616.87 g·m-2·d-1、拉伸强度为113.18 MPa、断裂伸长率为24.48%。

Effects of Plasticizer on the Properties of Bacterial NanocelluloseChitosan Composite Film

Bacteria nanocellulose/chitosan(BNC/CS) composite film was prepared by the casting method. The effects of glycerin, polyethylene glycol, and acetyl butyl citrate three plasticizers on the light transmittance, water vapor transmission rate, and mechanical properties of BNC/CS composite film were studied. The morphology and structure of the composite film were characterized by a scanning electron microscope, Fourier Transform Infrared, and X-ray Diffraction. BNC and CS had good compatibility, the BNC/CS composite film had high transparency and had a shielding effect on ultraviolet light, and all three plasticizers can achieve the plasticization effect by weakening the hydrogen bond between BNC and CS molecules and changing the crystal structure of the composite film. The three plasticizers can reduce the water vapor transmission rate of the composite film, improve the moisture retention performance of the composite film, and their contents have little effect on the performance. The three plasticizers all improved the plasticity of the bacterial nanocellulose-chitosan composite film. Among them, glycerin had the best enhancement effect, followed by polyethylene glycol, and finally acetyl butyl citrate. When adding 5% glycerol as a plasticizer, the composite membrane had better comprehensive performance, water vapor transmission rate, tensile strength, and elongation at break are 1 616.87 g·m-2·d-1, 113.18 MPa and 24.48%, respectively.