Gas transport properties of biphenol polysulfones

Abstract

Gas sorption and transport properties at 35 °C are reported for the polysulfone based on 4,4'-biphenol (BIPSF) and corresponding polysulfones with methyl ring substitutions, tetramethylbiphenol polysulfone (TMBIPSF) and hexamethylbiphenol polysulfone (HMBIPSF). Comparisons are made to bisphenol A polysulfone (PSF) and tetramethylbisphenol A polysulfone (TMPSF). BIPSF and PSF have very similar transport characteristics. This is attributed to the similar packing behavior of these polymers. Tetramethyl substitution on the biphenyl rings increases permeability, while hexamethyl substitution does not lead to a comparable further increase but does enhance selectivity characteristics for certain gas pairs. Permeability values are discussed in terms of chain packing, fractional free volume, and sub-T, relaxation behavior.

Modified polysulfones 5: synthesis and characterization of tetramethyl polysulfones containing trimethylsilyl groups and their gas transport properties

“…This situation is reversed in the case of CO 2 /N 2 or CO 2 /CH 4 , where the permselectivity of the starting polymer 1b is greater than 1a. This is explained by Aitken et al [30] who reported that the diffusion and solubility coefficients for CO 2 are about 20 -25% higher for 1b than for 1a. It was also reported that the solubility coefficient for CH 4 follows the same trend, but for N 2 it is reversed.…”

“…This differs from the results for the TMPPSf-5,11-TMS series 3b and 5b, which show that there is a continuous and quasi-linear significant increase in P(O 2 ) with increasing DS, but with only a concomitant moderate loss in selectivity. Aitken et al [30] published a comprehensive explanation of the gas transport property differences between polymers 1a and 1b in terms of the effects of structure on solubility and diffusivity coefficients. The O 2 / N 2 separation factor is smaller for 1b than for 1a.…”

Gas transport and dynamic mechanical behavior in modified polysulfones with trimethylsilyl groups: effect of degree of substitution

“…Thus the gas permeability is rather well correlated with small-scale local chain motions [23,24], which have been normally characterized by sub-T g relaxation behavior (i.e., secondary relaxation or ␥-relaxation). The ␥-relaxation behavior has been investigated by DMA to understand the relationship between small-scale local chain motions and gas permeability [2,4,5,22,25,26].…”

“…Numerous studies on the permeation of gases through polymers have been carried out in an attempt to understand transport mechanism [1][2][3][4][5][6][7] and thereby to overcome the 'trade-off' trend in the relationship between gas permeability and permselectivity that is properties depend primarily on the packing density and the mobility of polymeric chains. The former has been frequently interpreted in terms of free volume, specific volume and d-spacing and the latter through dynamic mechanical analysis (DMA), nuclear magnetic resonance (NMR), and dielectric relaxation [10][11][12][13].…”

Simulations of gas transport in membranes based on polynorbornenes functionalized with substituted imide side groups

“…It has been found that restriction of both packing efficiency and chain mobility may increase gas permeability with minimum permselectivity losses. Families of polycarbonates [3][4][5][6][7][8][9], polysulfones [4,[10][11][12][13][14][15][16][17], polyimides [18][19][20][21][22][23][24][25], polyoxydiazoles and polytriazoles [26,27], aromatic polyesters [28][29][30][31][32], and methyland phenyl-substituted polyphenylene ethers [33,34], have been optimized using these guidelines. Work has been reported showing that the substitution of hydrogen atoms by methyl groups in the four symmetrical ring positions of bisphenol A leads to polycarbonates, polysulfones and polyarylates that are about four times more permeable to gases than the corresponding unsubstituted materials without losing permselectivity [33].…”