Document Type

Article

Publication Date

11-7-2019

Publication Title

Polymer

Volume

182

Abstract

Highlights

  • Stable rigid monomers result in polyimides with higher Mw, Tg, TR, and the more superior separation performance.
  • Thermal rearrangement improved ideal gas separation by 1.5 to 2.0 orders of magnitude.
  • Thermal rearrangement resulted in an enhanced thermal, mechanical and chemical properties of the produced membranes.

Polymeric membranes remain and will most likely continue to be the most practical cost-effect chemical constructs for gas separation processes, provided that novel polymers are developed to overcome current and persisting limitations facing exiting membranes. Here, we report a methodical and systematic study of the structure-property-function relations of standard polyimide membranes and their implications on the separation performance. Three different dianhydrides (PMDA, ODPA and BTDA) with a single diamine (BisAPAF) were used to synthesize polyimide membranes via azeotropic imidization. The membranes were characterized, thermally rearranged and tested using gas pairs. Characterization was conducted prior and post thermal treatments in order to investigate the influence of the chosen precursors on the ideal selectivity properties. The resulted molecular weights of the polyimides were determined to be between 25,000 and 94,000 g/mol. The glass transition temperatures varied between 220 °C and 270 °C, and the degradation temperatures were at an average of 550 °C. The gas separation performance of all membranes significantly improved post thermal rearrangement, especially the APAF-BTDA polyimide which surpassed the so-called selectivity/permeability upper bound for CO2/CH4, N2/CH4 and CO2/N2 gas pairs.

DOI

10.1016/j.polymer.2019.121825

ISSN

0032-3861

Download

Share

COinS