The relationship between the chemical structure and thermal conversion temperatures of thermally rearranged (TR) polymers

Thermally rearranged polybenzoxazoles and poly(benzoxazole-co-imide)s from ortho-hydroxyamine monomers for high performance gas separation membranes

“…In agreement with previous results [20,29], it was noted that the initial temperature in the rearrangement process, and the conversion rate into PBO as well, was controlled by the chain rigidity of HPI, revealing an important dependence on T g .…”

“…As reported previously [16,17,25,29], the thermal rearrangement process of HPIs can be studied by thermogravimetric analysis just by monitoring the evolution of two distinct weight loss steps. In the first step, in the range of 300-500°C, mass spectroscopy shows CO 2 release, the result of thermal rearrangement to form the PBO structure.…”

Effect of polymer structure on gas transport properties of selected aromatic polyimides, polyamides and TR polymers

“…Two distinct regions of mass loss are observed. Such results are common for TR polymers,where the first stage of mass loss is attributed to thermal rearrangement, and the second stage of mass loss is attributed to thermal degradation 2,[5][6][7][8]16,21,24,[54][55][56][57][58][59][60][61]. By comparing these regions, the temperature range and intensity of thermal rearrangement and degradation can be identified.…”

“…4 Calle et al and Guo et al demonstrated that the onset temperature for thermal rearrangement correlates with the glass transition temperature of the polyimide. [5][6][7] Guo et al and Sanders et al demonstrated that transport properties could further be tuned by modifying the size of the ortho-functional leaving group, which, in addition to CO 2 , is also evolved during thermal rearrangement. [8][9][10] The thrust of this paper is to extend the current understanding of gas separations with TR polymers by investigating several polymer backbone chemistries.…”

Separation of CO2 from humidified ternary gas mixtures using thermally rearranged polymeric membranes

“…In addition, the issue with the low flux is particularly a concern for flue gas CO2 capture, where the feed pressure is low (slightly above 1 bar) and the gas volumes are enormous. In this case, membranes exhibiting high permeabilities such as polymers with intrinsic microporosity (PIMs) and thermally rearranged (TR) polymers [17,18,19,20,21,22] has become an important field of study. Membranes prepared with thermal rearranged polymers show excellent separation performance due to their complex microstructure whose cavity size and distribution can be opportunely tuned by the choice of template molecules and thermal treatment protocols [23,24,25,26,27].…”