PVDF membrane formation by diffusion‐induced phase separation‐morphology prediction based on phase behavior and mass transfer modeling
PVDF membrane formation by diffusion‐induced phase separation‐morphology prediction based on phase behavior and mass transfer modeling
复制标题
DOI：
10.1002/(sici)1099-0488(19990815)37:16
复制
发表时间：
1999-08
期刊：
影响因子：
--
通讯作者：
L. Cheng;D. Lin;Chien-Hsieh Shih;A. Dwan;C. Gryte
中科院分区：
文献类型：
--
作者：
L. Cheng;D. Lin;Chien-Hsieh Shih;A. Dwan;C. Gryte
采用理论和实验相结合的方法研究了水（非溶剂）-DMF（溶剂）-PVDF体系在25°C下的平衡相行为。使用二元相互作用参数，χij，先前获得的，理论相边界进行了计算，并发现密切匹配的测量的双节点和结晶诱导的凝胶化数据。采用等温浸渍-沉淀法在不同的纺丝液和浴条件下制备了膜。所形成的膜表现出广谱的形态：在一个极端，获得不对称结构，其特征在于连续的紧密表皮和由平行的大空隙和细胞孔组成的亚层;在另一个极限，产生无表皮微孔膜，其中球形颗粒填充到双连续结构中。用小角光散射、扫描电镜和差示扫描量热法研究了PVDF凝胶和膜的结晶特性。此外，扩散轨迹和浓度分布在沉淀前的膜溶液中的浸渍过程进行了计算。这些结果合理地预测了在膜中观察到的各种形态。© 1999 John Wiley & Sons，Inc.聚合物科学杂志B：聚合物物理37：2079-2092，1999
The equilibrium phase behavior of water (nonsolvent)-DMF (solvent)-PVDF system at 25°C was investigated via both theoretical and experimental approaches. Using binary interaction parameters, χij, obtained previously, the theoretical phase boundaries were computed and were found to match closely the measured binodal and crystallization-induced gelation data. Membranes were prepared using the isothermal immersion-precipitation processes in various dope and bath conditions. The formed membranes demonstrated a broad spectrum of morphologies: At one extreme, asymmetric structure was obtained featuring a continuous tight skin and a sublayer composed of parallel macrovoids and cellular pores; at the other limit, skinless microporous membrane was produced with spherical particles packed into a bi-continuous structure. The crystalline characters of PVDF gels and membranes were examined by small angle light scattering, scanning electron microscopy, and differential scanning calorimetry techniques. In addition, diffusion trajectories and concentration profiles in the membrane solution before precipitation were calculated for the immersion process. These results predicted reasonably the various morphologies observed in the membranes. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 2079–2092, 1999