QAPVA/PMPVA复合物膜对95%乙醇脱水的IR研究

Infrared Spectral Studies of Separation of QAPVA/PMPVA Complex Membrane for Dehydrating Water of 95% Ethanol

季铵化聚乙烯醇（QAPVA）与磷酸单酯化聚乙烯醇（PMPVA）自组装成聚离子复合物（PIC）膜。PIC膜用95%乙醇中浸泡48 h,在20-120℃（间隔20℃）下测定吸水后PIC膜的IR,分析了〉3000 cm^-1OH伸缩振动基频（νOH）随温度变化情况,探讨了水与膜中OH的氢键作用。由于νOH在3000 cm^-1以上重叠严重,结合1300-1700 cm^-1水与PIC膜中离子键的静电作用,采用二维相关分析提高分辨率,定性描述了95%乙醇中水与PIC膜之间的结合方式。结果表明：〉3000 cm^-1νOH的重叠谱带得到了分辨,证明了水与膜内OH缔合优先吸附渗透,随温度变化早于膜内的OH自缔合被解吸与乙醇分离;确认了水和PIC膜内聚电解质基团的吸收,证明了水与聚电解质基团靠静电作用被吸附,随温度升高被解吸与乙醇分离。文章为PIC膜用于有机物脱水研究提供了一种简便高效的方法。

Quaternized polyvinyl alcohol（QAPVA） and phosphate monoester polyvinyl alcohol（PMPVA） were self-assembled into polyion complex（PIC） membrane.The infrared spectra（IR） of PIC membrane dipped in 95% ethanol for 48 h were studied in the temperature range of 20-120 ℃ with an interval of 20 ℃ by analyzing the temperature dependent variations of OH stretch vibration base bands（νOH） at 〉3 000 cm^- 1.Hydrogen-bond of water in 95% ethanol with PIC was studied.Since the νOH strongly overlapped at 〉3 000 cm^-1,combined with the static electric effect between water in 95% ethanol and ion-bond of PIC at 1 300-1 700 cm^-1,two-dimensional infrared（2DIR） correlation analysis was applied to describe the possible combined modes between PIC and water in water-alcohol.The result shows that the νOH overlapped was distinguished at 〉3 000 cm^-1,the change of water with varing tempertature was earlier than the intra-membrane OH self association and water was desorbed to separate from ethanol.The absorption peak of water and poly-electrolyte group intra-PIC membrane was identified.The water combined with ion-bond in PIC membrane by static electric effect was adsorbed with the temperature going up and separate from ethanol.The present study provides a simple method for investigating the separation performance of PIC membrane used in dehydration of organic compounds.