环糊精复合薄膜制备及扩散性能研究

Preparation and Diffusion Performance Study of Cyclodextrin Composite Film

摘要: 成本低廉的膜材料中扩散常数控制对其应用领域的拓展具有极为重要的地位。通过共混法将β-环糊精引入聚乙烯醇(PVA)与水性聚氨酯(PU)基质中，探究其微观结构对水分子扩散行为的影响机制，为高性能分离膜的设计提供依据。通过优化环糊精添加量和薄膜制备工艺，调控复合膜的性能，并借助扫描电子显微镜、傅里叶变换红外光谱、接触角测试、吸水率测定及渗透实验等手段，综合分析了薄膜的形貌、化学结构、亲水性及水分子传输性能。研究结果表明，环糊精在薄膜基质中分散均匀，无明显团聚。FTIR谱图显示3440 cm⁻¹处羟基峰强度随环糊精含量增加而增强，环糊精与PVA/PU间融合良好。复合膜的亲水性得到显著改善，接触角从85.1˚ (空白)降至73.9˚ (10%环糊精)。吸水率随环糊精添加量上升，10%改性薄膜24 h吸水率达250%。渗透实验中，去离子水在改性薄膜中的扩散常数随环糊精含量呈线性增长，10%组扩散常数为1.31 × 10⁻⁸ m²/s，生理盐水扩散常数较低为0.89 × 10⁻⁸ m²/s。该方法利用了环糊精的结构，可有效调控复合薄膜的扩散性能，具有良好的应用潜力。

Abstract: The diffusion constant of low-cost membrane materials plays a crucial role in determining the expansion of their application fields. By incorporating β-cyclodextrin into the polyvinyl alcohol (PVA) and water-based polyurethane (PU) matrix through blending, the influence mechanism of the microstructure on the diffusion behavior of water molecules was explored, providing a basis for the design of high-performance separation membranes. By optimizing the addition amount of cyclodextrin and the film preparation process, the performance of the composite membrane was regulated, and through means such as scanning electron microscopy, Fourier transform infrared spectroscopy, contact angle measurement, water absorption rate determination, and permeation experiments, the morphology, chemical structure, hydrophilicity, and water molecule transport performance of the film were comprehensively analyzed. The results showed that cyclodextrin was uniformly dispersed in the film matrix without obvious aggregation. The intensity of the hydroxyl peak at 3440 cm⁻¹ increased with the increase in cyclodextrin content, and the fusion between cyclodextrin and PVA/PU was good. The hydrophilicity of the composite membrane was significantly improved, with the contact angle decreasing from 85.1˚ (blank) to 73.9˚ (10% cyclodextrin). The water absorption rate increased with the increase in the addition amount of cyclodextrin, and the 24-hour water absorption rate of the 10% modified film reached 250%. In the permeation experiment, the diffusion constant of deionized water in the modified film increased linearly with the cyclodextrin content, and the diffusion constant of the 10% group was 1.31 × 10⁻⁸ m²/s, while the diffusion constant of physiological saline was lower at 0.89 × 10⁻⁸ m²/s. This method utilizes the structure of cyclodextrin and can effectively regulate the diffusion performance of the composite membrane with good application potential.