通过羟氨缩合法合成了一系列不同比例“软-硬”段的PDMS-b-PPO共聚物,利用1H-NMR测定组分比,采用溶剂挥发法将其制备成膜并用于乙醇/水的渗透汽化分离,考察了PDMS-b-PPO共聚物的组分比对小分子在膜中溶解扩散性及膜微观结构的影响.利用接触角法测定了PDMS-b-PPO膜的溶解度参数,采用比重法计算了乙醇和水分子在膜中的相互作用参数及扩散系数,并通过AFM和EDS等手段对膜的微观结构进行表征.结果表明,PDMS-b-PPO膜具有微相分离的特征结构,随着膜中PDMS浓度的增加,膜的微相分离结构更加明显,乙醇在膜中的溶解和扩散能力明显增强.
A series of polydimethylsiloxane-bloek-polyphenylene oxide (PDMS-b-PPO) copolymers with different compositions of "hard-soft" segments were synthesized through a hydroxyl-amino condensation reaction. The PDMS concentration was calculated based on the ^1 H-NMR result of the PDMS-b-PPO copolymers. The PDMS-b-PPO membranes were prepared via a solvent evaporation method and employed in the separation of ethanol/water mixtures by pervaporation. The effects of varying the composition on the mass transfer properties and morphology of the PDMS-b- PPO membranes were studied. The solubility and diffusion properties of ethanol and water in PDMS-b-PPO membranes were tested, and the micro-phase separation morphologies were observed by AFM and EDS. The results showed that the membranes preferentially absorbed ethanol. With the increasing of PDMS concentration in the PDMS-b- PPO membrane, the diffusion ability of both ethanol and water in the membranes was enhanced, and furthermore, the value for ethanol increased more rapidly than the value for water.