Thermally Rearranged Polymeric Membranes for Gas Separation

Abstract

As a new category of glassy polymer membranes with microporosity, thermally rearranged (TR) polymeric membranes have been of interests for gas separation applications worldwide, due to the high gas permeability and reasonable selectivity. In this project, factors influencing the thermal rearrangement process were systematically investigated from the aspects of both membrane physicochemical properties and gas separation performance. The effects of process parameters and TR precursor properties including (a) degree of thermal conversion from an ortho-functional polymer precursor towards polybenzoxazole structure, (b) thermal history changes and thermal crosslinking reactions induced by different rearrangement temperatures, (c) purging environments (nitrogen versus air) during thermal rearrangement and (d) incorporation of cardo moiety into polymer backbone by copolymerization, were explored. Various characterization techniques including elemental analysis, TGA, TGA-IR, DSC, ATR-FTIR, XPS, XRD and Positron Annihilation Lifetime Spectroscopy (PALS) have been utilized to thoroughly examine the evolution of the polymer membrane properties during thermal rearrangement.