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首页> 外文期刊>Journal of Applied Polymer Science >Morphology of integral-skin layers in hollow-fiber gas-separation membranes
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Morphology of integral-skin layers in hollow-fiber gas-separation membranes

机译：中空纤维气体分离膜中整体皮层的形态

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The morphologies of polymeric integrally skinned asymmetric gas-separation membranes are typically visualized as a thin gas-selective skin region supported by a nonselective, low-resistance porous structure. The validity of this visualization for defect-free and defective membranes was investigated via scanning electron microscopy (SEM) in combination with traditional gas-permeation measurements for previously reported ultrathin defect-free hollow-fiber membranes. Hollow-fiber membranes were formed via a dry-jet, wet-quench process with a spinning solution composed of Matrimid(R) polyimide and components of varying volatility. For all the defect-free membranes formed, SEM images revealed a prominent dense skin layer across the fibers' entire outer circumference. Skin-thickness estimates from 36 SEM images and N-2, O-2, and He pure gas-permeation measurements agreed to within 9, 7, and 24% for defect-free membranes with 150-, 300-, and 600-nm skin thicknesses, respectively. Defective membranes with O-2/N-2 gas selectivities of Knudsen values, nominally 50 and 80% of dense film values, exhibited a well-developed nodular, partially developed nodular, and uniform dense layer (no nodules) skin morphologies, respectively. These results provide in-depth experimental evidence for the existence of a distinct dense integral-skin layer and suggest that the presence of nodules in the membrane's final skin morphology correlate to gas-permeation defects. (C) 2003 Wiley Periodicals, Inc. [References: 44]
机译：聚合物整体蒙皮的不对称气体分离膜的形态通常可视化为由非选择性，低电阻的多孔结构支撑的稀薄的气体选择性皮肤区域。通过扫描电子显微镜（SEM）结合传统的气体渗透测量，对先前报道的超薄无缺陷中空纤维膜进行了研究，该可视化对于无缺陷和有缺陷膜的有效性。中空纤维膜是通过干喷湿法骤冷工艺形成的，纺丝溶液由Matrimid？聚酰亚胺和不同挥发性的成分组成。对于形成的所有无缺陷膜，SEM图像显示出在纤维的整个外圆周上都有明显的致密表皮层。根据36幅SEM图像以及N-2，O-2和He的纯净气体渗透率测量得出的皮肤厚度，对于无缺陷，具有150-，300-和600-nm膜的膜，其同意在9％，7％和24％之内皮肤厚度分别。具有Knudsen值的O-2 / N-2气体选择性的标称值分别为致密膜值的50％和80％的有缺陷的膜分别具有发达的结节，部分发达的结节和均匀的致密层（无结节）皮肤形态。这些结果为存在明显的致密整体皮肤层提供了深入的实验证据，并表明膜最终皮肤形态中结节的存在与气体渗透缺陷相关。 （C）2003 Wiley Periodicals，Inc. [参考：44]

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