Polyimide Membranes Derived from Poly(amic acid) Salt Precursor Polymers. 2. Composite Membrane Preparation

Abstract

A novel two-step process for fabrication of composite polyimide hollow fiber membranes using poly(amic acid) tertiary amine salts, PAAS, is described. In the first step, a precursor membrane is formed by depositing a thin PAAS polymer layer from an alcohol-based solution onto a porous hollow fiber substrate. In the second step, the final composite polyimide membrane is obtained upon thermal treatment of the precursor composite PAAS membrane at 150 °C. The novel process was demonstrated by preparing a composite polyimide membrane on a polysulfone hollow fiber substrate from the PAAS polymer (6FDA-ODA/Et 3N) derived from 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA), 4,4′-oxydianiline (ODA), and triethylamine. The surface layer and cross section of the precursor composite PAAS membrane and the final polyimide membrane were studied by SEM. The quantitative transformation of PAAS prepolymer into the respective polyimide by heat treatment at 150 °C was confirmed by ATR FT-IR analyses. Gas permeation characteristics of composite PAAS and polyimide membranes were measured and are reported.

Infrared Analysis of Electrostatic Layer-By-Layer Polymer Membranes Having Characteristics of Heavy Metal Ion Desalination

“…Also, Poly(acrylonitrile-co-acrylic acid) [P(ANco-AA)] membrane was used as a negatively charged base, while Poly(acrylonitrile-co-N,Ndimethyethyl ammonium bromide P(AN-co-EDAMA) was used as a positively charged substrate. [18,19] Their base membranes of P(AN-co-AA) and P(AN-co-EDAMA) were prepared by phaseinversion of their respective dimethyl sulfoxide solutions in water. [20] The base membranes of P(AN-co-AA) or P(AN-co-EDAMA) were orderly dipped in positive CTAC and negative PAA aqueous solutions.…”

Fabrication of Copper Nanoparticles in a Thick Polyimide Film Cured by Rapid Thermal Annealing

“…[28][29][30][31] The imidization process of BPDA-PDA type PAA is described in our previous paper. 19 Figure 1 shows the FT-IR spectra of 2.5 wt% PAA/Si, 10 wt% PAA/Si, and 10 wt% PI/Cu/SiO 2 /Si samples, both before and after curing by the RTA or in a furnace.…”

Synthesis and characterization of high performance poly(thioether imide)s via aromatic nucleophilic substitution reaction of isomeric AB-type monomers

“…However, tetracarboxylic dianhydrides and diamines are highly expensive and need multisteps to synthesize; meanwhile, tetracarboxylic dianhydrides are tend to hydrolyze and diamines are easily to be oxidized in the process of preservation. What is more, the intermediate polyamic acids in solution are known to be notoriously unstable and tend to depolymerize even at room temperature in storage for long period, because hydrolytic cleavage reaction readily takes place [7][8][9][10][11].…”