选择性透过CO2气体PVA/淀粉膜制备及性能研究

对聚乙烯醇(PVA)/淀粉膜进行接枝改性，引入含有叔胺基团的甲基丙烯酸二甲氨基乙酯(DMAEMA)，使其对CO₂气体具有选择性透过功能，并对CO₂透过量进行优化，研究其分子结构与性能的关系。红外光谱、X射线光电子能谱、原子力显微镜照片及透气测试结果证明，加入淀粉接枝DMAEMA共聚物后，PVA/淀粉改性膜对CO₂具有选择透过性。接枝共聚物的接枝率和添加量影响CO₂透过量，当添加1.5%(质量分数，下同)的接枝率为55.3%的接枝共聚物，膜的CO₂透过量由1.577 cm³/(m²·24 h·0.1 MPa)提高到45.786 cm³/(m²·24 h·0.1 MPa)，提高了28.03倍。X射线光电子能谱测试结果显示，改性膜透过CO₂后，N1s谱图中399.8 eV处的结合能减小，在401.8 eV结合能增大，可能CO₂与膜上叔胺基团发生反应，实现...

Preparation and performance of PVA/starch composite membranes with selective permeability of CO2

In this paper， PVA/starch composite membranes were grafted with dimethylaminoethyl methacrylate （DMAEMA） as a modifier. The composite membranes were endowed with a selective transmission function of CO₂ gas through introducing tertiary amine groups. The CO₂ transmission volume was optimized through exploring the relationship between the molecular structure and performance. Based on the characterization results from infrared spectroscopy， X?ray photoelectron spectroscopy （XPS）， atomic force microscopy， and permeability tests， the composites exhibited selective permeability to CO₂ after grafting DMAEMA into starch. The CO₂ transmittance of the DMAEMA?grafted starch increased by 28.03 times from 1.577 to 45.786 cm³/（m²?24 h?0.1 MPa） at a graft rate of 55.3 wt% and a copolymer amount of 1.5 wt%. The XPS results indicated a decrease in binding energy at 399.8 eV in N1s spectrum and an increase in binding energy at 401.8 eV after CO₂ permeates the composite membranes. CO₂ can react with tertiary amine groups on the composite membranes to realize an internal transfer. Therefore， the surface roughness of the composite membranes increased， and there was a transition from the curled state to the extended state for the molecular chains on the membrane surface， resulting in an increase in the contact with CO₂.