Synthesis and properties of novel sulfonated polyimides from 2,2′‐bis(4‐aminophenoxy)biphenyl‐5,5′‐disulfonic acid

Abstract

Novel sulfonated polyimides (SPIs) were prepared from 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTDA), 2,2Ј-bis(4-aminophenoxy)biphenyl-5,5Јdisulfonic acid (oBAPBDS) with nonlinear configuration, and common nonsulfonated diamines. Water uptake (WU) in liquid and vapor, water stability, and proton conductivity of the resulting SPI membranes were investigated. They were soluble in m-cresol and dimethylsulfoxide, and their WUs in liquid were much larger than those of the SPIs from other sulfonated diamines with linear configuration such as 4,4Ј-bis(4aminophenoxy)biphenyl-3,3Ј-disulfonic acid (BAPBDS). NTDA-oBAPBDS membrane was soluble in water at room temperature, whereas all the oBAPBDS-based copolyimide membranes were insoluble in water and maintained mechanical strength after being soaked in distilled water at 80°C for 40 -1000 h. This much improved water stability was due to the enhanced solubility stability of membrane toward water. The water vapor sorption isotherms were rather similar between the SPIs with the nonlinear and linear configurations of sulfonated diamine moieties. The present SPIs with IECs of 1.8 -2.6 meq/g, including NTDA-BAPBDS, showed reasonably high proton conductivities under the highly humid conditions and roughly fell on the same -WU relation line.

Synthesis and properties of novel side-chain-sulfonated polyimides from bis[4-(4-aminophenoxy)-2-(3-sulfobenzoyl)]phenyl sulfone

“…With an increase in a w , the water vapor sorption increased sigmoidally. The sigmoidal sorption isotherms have been explained by means of a superposition of dual-mode sorption and plasticization effect of sorbed water [25,26]. At low a w (!0.2), the sulfonic acid groups interact strongly with water molecules and act as water sorption sites, resulting in a Langmuir-type isotherm.…”

Preparation and properties of covalently cross-linked sulfonated copolyimide membranes containing benzimidazole groups

“…In the past decade great efforts have been made on the development of low cost and high performance sulfonated hydrocarbon polymer membranes and other membranes such as inorganic acid-doped membranes as the alternative PEMs for fuel cell application. Sulfonated hydrocarbon membranes have been the most widely studied PEMs, and among them six-membered ring sulfonated polyimides (SPIs) have been identified to be one of the most promising materials [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. To achieve high proton conductivity, sulfonated polymer membranes should have high ion exchange capacities (IECs).…”

On the Development of Naphthalene-Based Sulfonated Polyimide Membranes for Fuel Cell Applications

“…[23][24][25][26][27][28] We classified the sulfonated diamines into two groups. The sulfonated diamines such as BDSA, 4,4 0 -diamino-diphenyl-ether-2,2 0 -disulfonic acid (ODADS) and 4,4 0 -bis(4-amino-2-sulfophenoxy)biphenyl (iBAPBDS), where the electron-withdrawing sulfonic acid groups are bonded directly to the amino-phenyl rings, are noted as ''Type 1''.…”