Preparation of poly(vinyl alcohol)-based membranes with controllable surface composition and bulk structures and their pervaporation performance
Preparation of poly(vinyl alcohol)-based membranes with controllable surface composition and bulk structures and their pervaporation performance
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DOI：
10.1016/j.memsci.2012.05.037
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发表时间：
2012-10
影响因子：
9.5
通讯作者：
Wei Zhang;Xinzhen Zhao;Zhennan Zhang;Yunxia Xu;Xinping Wang
中科院分区：
文献类型：
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作者：
Wei Zhang;Xinzhen Zhao;Zhennan Zhang;Yunxia Xu;Xinping Wang
通过将 PVA/聚丙烯酸 (PAA) 溶液浇注到不同的基材上，制备了具有可控表面结构和本体特性的聚乙烯醇基膜。形成四种表面，即空气侧1和玻璃侧表面(用作基材的玻璃板)、空气侧2和PTFE侧表面(用作基材的聚四氟乙烯(PTFE)板)。在 PVA 浇铸溶液中任意给定的 PAA 含量下，所得膜的空气侧 1 和 PTFE 侧表面的亲水性低于相应的玻璃侧和空气侧 2。有趣的是，空气侧 1 和 PTFE 侧之间以及玻璃侧和空气侧 2 之间具有相似的表面组成。此外，在 PTFE 板上制备的膜表现出比在玻璃板上形成的膜更高的结晶度。通过感应底层基材，可以调整这些 PVA 基膜的表面成分和体积特性。进行了通过这些膜分离乙酸/水混合物的渗透蒸发实验，结果表明选择性渗透性主要取决于膜表面组成，而渗透性更显着地受膜本体特性的影响。这为高效膜结构优化和渗透汽化分离机理探索提供了可行的方法。
Poly(vinyl alcohol)-based membranes with controllable surface structures and bulk characteristics were prepared by casting PVA/poly(acrylic acid) (PAA) solutions onto different substrates. Four kinds of surfaces, namely the air-side 1 and glass-side surface (a glass plate used as substrate), the air-side 2 and PTFE-side surface (a polytetrafluoroethylene (PTFE) plate used as substrate), were formed. At any a given content of PAA in PVA casting solution, the air-side 1 and PTFE-side surfaces of the resulting membranes were less hydrophilic than the corresponding glass-side and air-side 2. Interestingly, there was similar surface composition between the air-side 1 and PTFE-side, and between the glass-side and air-side 2. Furthermore, the membranes prepared on a PTFE plate exhibited higher crystallinity than those formed on a glass plate. By an induction of the underlying substrates, the surface composition and bulk characteristics of those PVA-based membranes could be tuned. Pervaporation experiments for separating acetic acid/water mixtures through those membranes were carried out, and the results indicated that the permselectivity was mainly dependent on membrane surface composition, whereas the permeability was more significantly governed by membrane bulk characteristics. This provides a feasible method for the structure optimization of a high-efficient membrane and mechanism exploration in pervaporation separation.