Modeling and simulation of the phase‐inversion process during membrane preparation

Abstract

ABSTRACT:The objective of this work is to present a simple mathematical model to describe the main features of phase inversion by immersion precipitation. The model was developed for planar geometry and is used to simulate membrane synthesis. Two systems commonly used for membrane preparation were used for simulations: cellulose acetate/acetone/water and polyetherimide/N-methylpyrrolidone/water. The influence of nonsolvent addition to initial polymer casting solutions, solvent addition to the coagulation bath, and geometric variables, such as polymer film thickness, on the final precipitation conditions were studied through simulation and compared to available experimental data. The results are in good agreement with published results. [1][2][3] It is shown that polymer film composition profiles at the moment of precipitation may give important information about the structure and substructure of formed membrane. It is also shown, for both polymeric systems investigated in this work, that the dynamics of the mass transfer process seems to be much more important than the influence of the concentration on the diffusion and thermodynamic partition coefficients, as fair agreement with available experimental data was obtained even when these coefficients were assumed to be constant.

Solvent effect on morphology and CO2/CH4 separation performance of asymmetric polycarbonate membranes

“…Similar behavior was exhibited by the membranes prepared using the chloroform-alcohol solvents mixtures (Figs. [10][11][12]. The experimental data show a higher permeance for both CO 2 (Fig.…”

“…[10][11][12]]. A strong influence of the mass transfer process was expectedly predicted on the formation of the film structure as well as the substructure.…”

Phase diagram of ternary polymeric solutions containing nonsolvent/solvent/polymer: Theoretical calculation and experimental validation

“…For example, in polyethersolfune/N-methylpyrrolidone/ water, having the Kelley-Bueche Parameter [24], R ¼ 2:98, and noting that the Berghmans point in located on binodal curve, the common point of glass transition boundary, gelation boundary and binodal curve, it can be simply searched using Eq. (18). Upon determination of this point, as seen in Fig.…”

Effect of Bath Concentration on Coagulation Kinetics at the Early Stage during Wet Spinning of PAN Copolymer Nascent Fibers

“…The mutual diffusion coefficient of solvent and nonsolvent in the coagulation bath was taken equal to 1 × 10 −9 m 2 /s and typical values for the partition coefficients of solvent and nonsolvent Downloaded by [University of South Florida] at 06:50 08 October 2014 were 1.0 and 0.5, respectively. [22] In agreement with previous literature, [17,18] the model was built without taking the flow field into consideration.…”