2,2‐Bis[4‐(3,4‐dicarboxyphenoxy) phenyl]propane dianhydride (BPADA)‐based polyimide membranes for pervaporation dehydration of isopropanol: Characterization and comparison with 4,4′‐(hexafluoroisopropylidene) diphthalic anhydride (6FDA)‐based polyimide membranes

Abstract

Polyimides were synthesized from one-step polycondensation of BPADA and various diamines and were characterized with GPC, FTIR, NMR, DSC, and TGA. Polyimide membranes were prepared, and their hydrophilicity was estimated by contact angles and the free energies of interfacial interactions. Pervaporation properties were investigated for the dehydration of isopropanol, and comparisons were made between BPADA-based membranes and 6FDA-based membranes. The concentration coefficients of BPADA-based membranes were calculated from the linear moiety contribution method based on the results from 6FDA-based membranes, and they were compared to understand the effects of the feed concentration on pervaporation properties. The effects of temperature on permeation flux were studied with permeation activation energies for total flux and water flux in permeates. Moiety contribution factors for activation energies were used to correlate permeation flux and monomer moieties in the polymers, and reasonable results were obtained for BPADA. It is revealed that steric effects of monomers may change the diffusion properties, while functional groups are favorable to the changes in sorption properties.

Novel approach to determination of sorption in pervaporation process: a case study of isopropanol dehydration by polyamidoimideurea membranes

“…The transport properties of PAIU membrane developed in this work were compared with literature data for the case of pervaporation separation of the isopropanol‒ water mixture in composition closed to azeotropic point. Table 3 lists data on operating temperature and feed concentration as well as membrane characteristics in pervaporation: separation factor and total flux that have been obtained for different polymer membranes in a number of published works 8 , 9 , 37 – 41 . The value of the separation factor of the PAIU membrane exceeds that of many previously published reports.…”

Aromatic polyimide and crosslinked thermally rearranged poly(benzoxazole-co-imide) membranes for isopropanol dehydration via pervaporation

“…Among C-TR membranes, C-TR-5-5 displays the best separation performance with a normalized flux of 2138 gȝm/m 2 h and a water concentration in permeate of approximate 99.8 wt%, as shown in Figure 11. Table 1 compares the pervaporation performance in terms of permeability and selectivity for the membranes in this study with various pervaporation membranes available in literatures [34,[53][54][55][56][57][58]. Both the PI-5-5 and C-TR-5-5 membranes show comparable water permeability with other membranes.…”

Synthesis of Aromatic Polyimides Based on 3,4′-Oxydianiline by One-Pot Polycondensation in Molten Benzoic Acid and Their Application as Membrane Materials for Pervaporation

“…It is worth noting that developed PI-DA membrane demonstrates competitive performance compared to data reported in the literature combining relatively high separation factor and flux [ 28 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 ]. Moreover, the excellent long-term pervaporation stability makes the developed PI-DA membrane promising material for isopropanol dehydration.…”