Miscibility of polysulfone/poly(1-vinylpyrrolidone-co-styrene) blends and their application to the ultrafiltration membrane

Abstract

Miscibility of polysulfone (PSf) with various hydrophilic copolymers was explored. Among these blends, PSf gives homogeneous mixtures with poly(1-vinylpyrrolidone-co-styrene) copolymers [P(VP-S)] when these copolymers contained VP from 68 to 88 wt%. Microporous membranes for the ultrafiltration process were prepared from PSf blends with P(VP-S) copolymers. The membranes prepared from the PSf/P(VP-S) blends exhibited higher water flux than the membranes prepared from PSf irrespective of the VP content. The solute rejection examined with the membranes fabricated from the miscible blends was similar to that of PSf membrane. However, the solute rejection examined with the membranes fabricated from the immiscible blends was lower than that of PSf membranes.

Gas separation properties of 6FDA-based polyimide membranes with a polar group

“…1 An advantage of polymeric composite membranes is that their gas permeability and selectivity can be controlled by the combination of various polymer components. 2,3 Polyimides are prepared by the imidization of polyamic acids obtained from dianhydride and diamine. In the preparation of a polyimide membrane for gas separation, 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) is well known as an anhydride component of the membrane which exhibits both high selectivity and permeability compared to common glassy polymers.…”

Phase behavior of binary and ternary blends having the same chemical components and compositions

“…The equation-of-state theory was adopted to avoid empirical To extract information about interaction energy from the liquidliquid phase boundaries, it is assumed that to a good approximation these data correspond to the spinodal curve. [6][7][8][25][26][27] The morphology of blend observed at a reported phase separation temperature could be also characterized by a high level of phase interconnectivity in both the minor and major phase caused by spinodal decomposition. According to the lattice fluid theory, the spinodal condition for a compressible binary mixture can be written (1) where g is the free energy of mixing per unit volume and the subscripts 1 and indicate partial derivatives with respect to φ 1 (volume fraction) or (reduced density).…”

“…The detail background calculating the interaction energies involved in the miscible blends from the phase boundaries using the lattice-fluid theory combined with binary and interaction model was described in the previous papers. [6][7][8][18][19][20][21][22][23][24][25][26][27] The temperature at which phase separation caused by lower critical solution temperature, LCST, occurred, was measured by an annealing technique to access the closest true equilibrium temperature. The equation-of-state theory was adopted to avoid empirical To extract information about interaction energy from the liquidliquid phase boundaries, it is assumed that to a good approximation these data correspond to the spinodal curve.…”

“…The temperature at which phase separation caused by lower critical solution temperature, LCST, was measured by an annealing technique to access the closest true equilibrium temperature. 6,[25][26][27] …”

Miscibility of branched polycarbonate blends with poly(ethylene-co-1,4-dimethyl cyclohexane terephthalate) copolyesters

“…The phase homogenization temperature caused by the upper critical solution temperature (UCST) type phase behavior was measured by an annealing technique to access the closest true equilibrium temperature. [26][27][28][29][30][31] Changes in morphology of blends with temperature were also observed by an image analyzer [Bummi Universe, model:…”