Synthesis and gas permeation properties of thermally rearranged poly(ether-benzoxazole)s with low rearrangement temperatures

Abstract

A series of poly(ether-benzoxazole)(PEBO) for gas separation were prepared from 9,9-bis[4-(4-amino-3-hydroxylphenoxy)phenyl]fluorene based hydroxyl-containing poly(ether-imide)s (HPEIs) with low rearrangement temperatures.

Enhanced gas separation and mechanical properties of fluorene-based thermal rearrangement copolymers

“…43 In addition, the rigid and large volume uorene groups are helpful to hinder the entanglement and rotation of molecular chain, and increase the spacing between the molecular chains, resulting in high permeabilities of TR membranes. [44][45][46] Generally, TR polymers derived from rigid macromolecular chains exhibit excellent gas separation properties, but they oen require higher rearrangement temperatures and show poor mechanical properties. On the contrary, TR polymers based on exible chain skeletons show lower rearranged temperatures and higher gas selectivities, but the gas permeabilities are relatively weakened to some extent.…”

“…On the contrary, TR polymers based on exible chain skeletons show lower rearranged temperatures and higher gas selectivities, but the gas permeabilities are relatively weakened to some extent. 45,46 Hence, adjusting the rigidity of macromolecular chain by copolymerization is an effective way to obtain TR membranes with excellent comprehensive properties.…”

“…Our research group found that the TR polymers derived from 9,9-bis(3-amino-4-hydroxyphenyl)uorene (BAHPF) displayed poor mechanical properties, lm-formation and high thermal rearrangement temperatures, while the TR polymers based on 9,9-bis[4-(4-amino-2-hydroxyphenoxy)phenyl]uorene (BAHPPF) exhibited good lm-formation and mechanical properties, but low gas permeabilities. 45,46 It is expected that the TR membranes exhibit excellent separation performance and moderate mechanical properties to meet the practical applications. Therefore, in this study, a series of TR copolymer membranes were prepared by the copolymerization of BAHPF, BAHPPF and 2,2 0 -bis(3,4 0 -dicarboxyphenyl)hexauoropropane dianhydride (6FDA), followed by thermal imidization and further rearrangement.…”

Phthalide-containing poly(ether-imide)s based thermal rearrangement membranes for gas separation application

“…[21][22][23][24][25][26][27][28] In recent years, thermal rearrangement (TR) polymers have been developed and investigated by researchers in the eld of membrane separation. [29][30][31][32][33][34] Due to the transition from imide ring to benzoxazole structure, hydroxyl-containing polyimide (HPI) is transformed into polybenzoxazole (PBO), and a large amount of small molecule gas CO 2 is released. [35][36][37][38][39][40][41] TR polymers exhibit excellent gas permeability and moderate selectivity because of unique "hourglass" micropore structure, which have become a new generation of gas separation membrane materials.…”

“…42 The gas separation process of TR polymer is mainly followed by the solution-diffusion mechanism, accompanied by the sieving mechanism due to the existence of pore structures. According to the literatures, [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44] the rearrangement reaction and gas separation performance of TR polymers are mostly affected by many factors, such as chemical structure, glass transition temperature (T g ), thermal treatment atmosphere, time and temperature. For example, the HPI containing exible linkage is easy to rearrange at a relatively low temperature because of better motion ability of chain segment, but the increase of gas permeability is not very signicant.…”