聚乙烯二甲基硅氧烷-聚偏氟乙烯复合分离膜的性能

Properties of Polyvinyl Dimethylsiloxane-Polyvinylidene Fluoride Composite Separation Membranes

为预测和评价聚偏氟乙烯(PVDF)和聚乙烯二甲基硅氧烷(PVDMS)多孔中空纤维复合膜的气体分离性能,提出了孔分布模型·通过比较模拟和实验结果,证明理论预测和实验结果具有很好的一致性·应用干 湿相转化法制备了PVDF多孔中空纤维膜,并且采用浸涂技术在PVDF中空纤维膜上制成厚度约为5～12μm的PVDMS致密膜层·通过气体渗透测试估计PVDF多孔基底膜的结构参数,同时也以氮气/氧气为介质对PVDMS PVDF复合中空纤维膜的分离性能进行了评价·实验结果表明,该复合膜具有较高的分离选择性,要制得致密无缺陷的复合膜,PVDMS致密涂层厚度不应小于5μm·

A pore-distribution model was developed for predicting and evaluating gas separating property of polyvinyl dimethylsiloxane-polyvinylidene fluoride (PVDMS-PVDF) composite hollow fiber membranes. The experimental data of both permeability and selectivity are in good agreement with the theoretical results predicted by the pore-distribution model. The PVDMS-PVDF composite hollow fiber membranes were prepared through dry-wet phase inversion and dip-coating technique, of which the structural parameters of PVDF substrate membrane were estimated by gas permeation test, and the separating property was evaluated experimentally using N_2/O_2 as the medium. The experimental results indicated that the composite membrane has high selectivity/separating property and the thickness of PVDMS skin coat must be higher than 5 μm so as to be compact without defects.