A study of thermodynamics and kinetics pertinent to formation of PVDF membranes by phase inversion

被引：56

作者：

Sun, Andy Chenggui ^{[1
]}

Kosar, Walter ^{[2
]}

Zhang, Yufeng ^{[3
]}

Feng, Xianshe ^{[1
]}

机构：

[1] Univ Waterloo, Waterloo, ON N2L 3G1, Canada

[2] Arkema Inc, Fluoropolymers Grp, King Of Prussia, PA 19406 USA

[3] Tianjin Polytech Univ, Sch Mat Sci & Engn, State Key Lab Hollow Fiber Membrane Mat & Proc, Tianjin 300160, Peoples R China

来源：

DESALINATION | 2013年 / 309卷

基金：

加拿大自然科学与工程研究理事会;

关键词：

Poly (vinylidene fluoride); Membrane; Phase inversion; HOLLOW-FIBER MEMBRANES; POLY(VINYLIDENE FLUORIDE); PRECIPITATION KINETICS; ASYMMETRIC MEMBRANES; SOLVENT EVAPORATION; PERMEATION; DOPE; ELECTROLYTES; PERFORMANCE; MORPHOLOGY;

D O I：

10.1016/j.desal.2012.10.005

中图分类号：

TQ [化学工业];

学科分类号：

0817 ;

摘要：

Poly (vinylidene fluoride) (PVDF) is a family of hydrophobic fluoropolymers with a unique polarity that enables certain solvents to dissolve them. Because of the selective solubility, PVDF membranes can be fabricated by the phase inversion technique. In this work, the thermodynamic and kinetic aspects pertinent to membrane formation by the phase inversion process were investigated for different grades of PVDF polymers developed by Arkema Inc. The phase separation data (thermodynamics) and the rates of solvent evaporation and polymer precipitation (kinetics) were determined. The phase boundary determines the nonsolvent content that the polymer system can tolerate without causing precipitation, while the kinetics of polymer precipitation influences not only the ultimate structure of the membrane but also the gelation time required for the membrane to solidify during the wet step. As the polymer precipitation is due to exchange of solvent in the polymer system with the nonsolvent in the gelation bath, the polymer precipitation kinetics was characterized by the solvent-nonsolvent exchange rate and the additive leaching rate. The partial evaporation of solvent from the surface of nascent membrane in the dry step, which influences subsequent polymer precipitation in the wet step, was quantified by an empirical equation. (C) 2012 Elsevier B.V. All rights reserved.

引用

页码：156 / 164

页数：9