PVA基聚离子复合物膜的结构与性能研究

Study on the Structure and Performance of PVA-based Polyion Complex Membrane

聚乙烯醇接枝聚乙烯氯化铵(PVA-g-PVAC)与聚乙烯醇接枝聚丙烯酸钠(PVA-g-SPA)自组装PVA基聚离子复合物(PPIC)。利用红外光谱(IR)对PPIC的结构进行表征。PPIC膜的SEM照片表面呈现有序孔状结构,有利于水的吸收。采用差示扫描量热法(DSC)测定了PPIC的耐热性。PPIC水溶液pH=5(反离子等摩尔复合)时,膜耐水性最好;PPIC膜的耐水性随乙醇浓度的增加或膜退火温度升高而提高。测定了PPIC复合膜对93%(体积分数)高浓度乙醇废水的渗透汽化性能,分离因子980,渗透通量1485g.(m2h)-1。

Polyvinyl alcohol（PVA）grafting polyvinyl ammonium chloride（PVA-g-PVAC） and PVA grafting sodium polyacrylate（PVA-g-SPA） self-assembled into PVA-based polyion complex（PPIC）.The chemical structure of PPIC was identificated by IR.The SEM image of PPIC membrane showed that there was ordered porous morphology at the surface which was beneficial to water absorption.The thermostability of PPIC was tested by DSC.The water resistance of the PPIC membranes is the best when the pH of the assembly solution is 5（composited by equimolar counterions,pH approached or equaled to isoelectric point（IEP））.The water resistance of the PPIC membranes was improved with the increasing of annealing temperature and ethanol concentration.The results showed that the PPIC membrane was suitable for the separation of ethanol/water system.Meanwhile,the pervaporation of PPIC composite membrane was tested and showed that the permeation flux was 1485g·（m2h）-1 and the separation factor was 980 for wastewater of high concentration high concentration ethanol waste water（ethanol 93%（volume fraction））.