摘要
聚乙烯醇-N,N-二甲基-3-氨基-2-羟基丙基醚的季铵化产物(quaternized PVA-N,N-dimethyl-3-amido-2-hydroxy-propyl ether,简称QPVA)与硫酸单酯化聚乙烯醇(sulphate monoesterified polyvinyl alcohol,简称SMPVA)自组装聚离子复合物(self-assembled polyion complex,简称SAPIC),自组装溶液pH=7时,膜在水中的溶胀度最小.SAPIC均质膜在60vol%～90vol%(间隔10%)乙醇中浸泡48h,观察不同浓度乙醇中水在均质膜中的扩散行为.SAPIC均质膜在95%乙醇中浸泡48h,在20～120℃(间隔20℃)下,观察乙醇中水在膜中的汽化行为.应用FTIR技术跟踪两类吸水膜,确认了水和膜内聚离子基的吸收.改变浓度的一维(1D)和二维(2D)FTIR相关分析表明,渗透过程中形成两种状态的水,游离水和缔合水,随乙醇中水的增加游离水优先变化.游离水靠静电作用与膜内聚离子基优先缔合形成缔合水;改变温度的1D-和2D-FTIR显示,汽化过程中也存在两种状态的水,游离水和缔合水,随温度升高游离水优先变化.游离水较缔合水优先挥发,脱离膜与乙醇分离.同时测定了SAPIC复合膜对95%乙醇/水的渗透汽化性能,分离因子870,渗透通量1400g/(m2·h).为SAPIC膜用于乙醇脱水的渗透汽化过程研究提供了一种简便的方法.
Quaternized PVA-N,N-dimethyl-3-amido-2-hydroxy-propyl ether（QPVA） and sulphate monoesterified polyvinyl alcohol （SMPVA） self-assembled into polyion complex （SAPIC）,the swelling ability of SAPIC membranes in water was the least when the self-assembled solution＇s pH value was 7. The homogeneous SAPIC membranes were dipped in ethanol of different concentrations 60 vol%～90 vol% （with 10% as interval） for 48 h,and the permeation behavior of water in ethanol of different concentrations was observed in these homogeneous SAPIC membranes.The homogeneous SAPIC membranes were dipped in 95 vol% ethanol for 48 h,and the pervaporation behavior of water in 95 vol% ethanol was observed in the temperature range of 20～120℃ with an interval of 20℃ in homogeneous SAPIC membranes.A novel experimental approach using FTIR spectroscopy was applied to follow up the scent of the two types of membranes.The absorption peaks of water and poly-electrolyte groups in SAPIC membranes were identified in 1D-or 2D-FTIR spectra and showed that two states of water,free water and associating water,were formed during permeation by polyion groups in SAPIC.Free water first associated with polyion groups in SAPIC membranes with increase of water in ethanol,thus associated water was formed in SAPIC membranes.The 1D-or 2D-FTIR results also showed that two states of water,free water and associating water,esisted during pervaporation in SAPIC membranes.The free water changed earlier than associated water,and free water was first desorbed with increase of temperature and was separated with ethanol.The pervaportion of SAPIC composite membranes was tested,and the results showed that the permeation flux was 1400 g/（m^2·h）,and the separation factor was 870 for water/ethanol system （containing 95 wt% ethanol）.A simple and convenient method was set up for studying the dehydration process of ethanol by using SAPIC membranes.
出处
《高分子学报》
SCIE
CAS
CSCD
北大核心
2008年第12期1154-1159,共6页
Acta Polymerica Sinica
基金
国家重点基础研究发展计划(973计划
项目号2003CB615701)资助项目
