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Effect of posttreatment on morphology and properties of poly(ethylene‐ co ‐vinyl alcohol) microporous hollow fiber via thermally induced phase separation
Author(s) -
Lv Rui,
Zhou Jing,
Du Qiangguo,
Wang Haitao,
Zhong Wei
Publication year - 2007
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.25685
Subject(s) - vinyl alcohol , shrinkage , materials science , microporous material , fiber , chemical engineering , polymer chemistry , crystallization , acetone , morphology (biology) , methanol , polymer , solubility , evaporation , vinyl acetate , composite material , chemistry , organic chemistry , thermodynamics , physics , biology , engineering , genetics , copolymer
Poly(ethylene‐ co ‐vinyl alcohol) (EVOH) hollow fiber membranes were prepared by thermally induced phase separation (TIPS) process. Water, methanol, and acetone were used to extract the diluents in the fibers, respectively. Bigger shrinkage of fibers during extractant evaporation was observed when water or methanol was used. Their interaction parameters with EVOH were calculated via Hansen solubility, respectively. The mechanism of hollow fiber volume shrinkage was discussed. It was found that affinity of the extractant with polymer was the critical factor except for the surface tension of extractant. Through the X‐ray diffraction analysis during extraction and evaporation, the crystallization behavior of the polymer was studied. From the SEM photos, it was observed that the volume shrinkage was derived from the collapse of porous structure. The fiber sample extracted by acetone had similar morphology with the sample freeze‐dried. The gas and water permeability were also measured and the results were coincident with the morphology of fibers and shrinkage data. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 4106–4112, 2007