Formation of crystalline EVAL membranes by controlled mass transfer process in water–DMSO–EVAL copolymer systems
出版日期:1998-06-01 00:00:00
著者:鄭廖平; Cheng, Liao-ping; Young, Tai-horng; You, Wei-ming
單位:淡江大學化學工程與材料工程學系
出版者:Amsterdam: Elsevier BV
著錄名稱、卷期、頁數:Journal of membrane science 145(1), pp.77-90
摘要:The effect of solvent content in the coagulation bath on the formation of poly(ethylene-co-vinyl alcohol) (EVAL) membranes by isothermal immersion–precipitation in water–dimethylsulfoxide (DMSO)–EVAL system has been investigated. As a homogeneous EVAL dope is immersed in a harsh bath, e.g., water, instant precipitation occurs initiated by the liquid–liquid demixing process. The formed membrane exhibits an asymmetric morphology with extensive finger-like macrovoids, similar to that observed in most amorphous polymeric membranes. On the other hand, if precipitation takes place in a soft bath containing a substantial amount of solvent, crystallization, rather than liquid–liquid demixing, starts to dominate and a skinless, bi-continuous, particulate membrane becomes the precipitated product. The immersion–precipitation process for the present system has been modeled as a ternary mass transfer problem. The calculated diffusion trajectories and concentration profiles illustrate reasonably the membrane morphologies formed in various immersion conditions.
關鍵字:EVAL; Crystallization; Liquid–liquid demixing; Immersion–precipitation; Diffusion
語言:en
ISSN:0376-7388
期刊性質:國外
收錄於:SCI EI
國別:NLD
出版型式:紙本