Polysulfones polymer blends

Modification of polymeric membrane materials through incorporation of hydrophi-licity results in membranes with low fouling behavior and high flux. Thus, literature presents sulfonated polysulfone/cellulose acetate blends applied in various compositions for obtaining ultrafiltration membranes, where their performance is improved by the inclusion of polyethyleneglycol into the casting solution as a nonsolvent additive in various concentrations. In this way, total polymer concentration, cellulose acetate, sulfonated polysulfone polymer blend composition, additive concentration, and their compatibility with polymer blends are optimized [133]. 

Manea, C. and Mulder, M. 2002. Characterization of polymer blends of poly-ethersulfone/sulfonated polysulfone and polyethersulfone/sulfonated poly-etheretherketone for direct methanol fuel cell applications. Journal of Membrane Science 206 443-453. 

Polymers of thietanes have been converted to the corresponding polysulf-oxides and polysulfones. A blend of preformed polyalkene [e.g., polypropylene] and poly(thietane) has been milled and molded and is used for making fibers, films, bottles, and pipes. ... 

Anhydrous sulfonated aromatic polymers are highly brittle. Recently [ 197], new materials with high mechanical strength were reported. They were prepared using a polymer blending technique by combining PBI and sulfonated polymers (S-PEEK or ort/zo-sulfonated polysulfone) (Fig. 28). 

In another study, Bowen et al. [42] prepared membranes from polymer blends of polysulfone and sulfonated poly(ether ether ketone) (PSf/SPEEK). It was reported that these membranes had high porosities, high charge densities, and pore sizes at the boundary between NF and UE For comparison, two commercial membranes of cellulose acetate and poly(ether sulfone) were chosen. Therefore, the following four membranes were involved in their study ... 

Kim DH, Kim SC (2008) Transport properties of polymer blend membranes of sulfimated and nonsulfonated polysulfones for direct methanol fuel cell application. Macromol Res... 

As of 1995, more than 30 different polymer blends were being used in the manufacture of membranes for hemodialysis and hemofiltration (Klinkmann and Vienken, 1995). The various membrane types used for renal replacement therapy can be divided into membranes derived from cellulose (83 percent of 1991 worldwide total) and from synthetic materials (the remaining 17 percent) (Klinkmann and Vienken, 1995). Synthetic membranes have been constructed from such materials as polyacrylonitrile (PAN), polysulfone, polyamide, polymethylmethacrylate, polycarbonate, and ethyl-vinylalchohol copolymer (Klinkmann and Vienken, 1995). In the United States, use of cellulosic materials for membrane construction predominates at around 95 percent of the total number of membranes used (Klinkmann and Vienken, 1995). 

Those initial studies of blends of PBI with various polyimides were subsequently extended to include other polymers. For example, it was shown that PBI and polysulfone form immiscible mixtures (Chung et al. 1993). However, it was later shown (Deimede et al. 2000a) that the introduction of functional groups, such as sulfonate groups, into the polysulfone polymer chain resulted in the formation of miscible blends with PBI. It was shown that the sulfonation level as well as the blend composition controls the observed miscibility. FT-IR analysis confirmed the presence of specific interactions between the PBI N-H group and the sulfonate groups on the polysulfone. 

Another polymer that has been investigated in several miscible polymer blends is polysulfone (PSF). Blends made from polyamide 11 (PAll) and sulfonated polysulfone (SPSF) were prepared by solution casting from dimethyl formamide (DMF) (Deimede et al. 2000b). In that work, differential scanning calorimetry (DSC) showed a melting point depression of the equilibrium melting point of the PAll. With lower degrees of sulfonation, less interaction between the two polymers was observed. FT-IR and FT-Raman spectroscopic techniques were used to confirm the nature of the specific interactions involved. 

In EP07708077A3 (Dabou et al. 1996), gas separation polymer membranes were prepared from mixtures of a polysulfone, Udel P-1700 and an aromatic polyimide, Matrimid 5218. The two polymers were proven to be completely miscible as confirmed by optical microscopy, glass transition temperature values and spectroscopy analysis of the prepared mixtures. This complete miscibility allowed for the preparation of both symmetric and asymmetric blend membranes in any proportion from 1 to 99 wt% of polysulfone and polyimide. The blend membranes showed significant permeability improvements, compared to the pure polyimides, with a minor change in the selectivity. Blend membranes were also considerably more resistant to plasticization compared with pure polyimides. This work showed the use of polysulfone-polyimide polymer blends for the preparation of gas separation membranes for applications in the separation of industrial gases. 

M. Weber, W. Heckmann, Compatibilization of polysulfone/polyamide-blends by reactive polysulfones-evidence for copolymer formation, Polymer BuUetin 40 (2-3) (1998) 227-234. 

Another area of possible interest in relation to sulfone polymer blends is the area of rubber modification for toughening of PSF to achieve supertoughness or enhanced ductility characteristics compared to unmodified polysulfone. Such supertough polysulfone formulations exhibit high notched impact strength values that are on par with those known for polycarbonate and PPSF. This tirea has been studied and reported on recently [45, 46]. 

The presence of reinforcanent in polymer (nano)composites (Thomas et al. 2011 Wen 2007) generally increases the value of E modulus due to restrictions of vibrations and short-range rotational motions (Bindu and Thomas 2013 Dufresne 2000 Liu et al. 2005 Musto 2006). Exceptions to this behavior exist, and one of them was reported on the EeS2/polyimide composite (Sava 2009). Incorporation of low quantities of pyrite microparticles restrains the possible physical interactions among polyimide chains, decreasing the rigidity of the composite relative to the pristine polyimide. Another situation was mentioned for an all-polymer composite obtained from a pair of incompatible polymers polysulfone (PSF) (the matrix polymer) and cross linked polydimethylsiloxane (PDMS) submicron particles (the disperse phase) (Racles et al. 2013). All-polymer composites contain polymer nanoparticles as the disperse phase in a polymer matrix and, from the point of view of properties, these are situated between polymer blends and polymer composites. The PDMS particles act like a plasticizer for the PSF matrix (E p p = 2 GPa, E psp/pp,Ms = 0.7 GPa). 

Linares, A. Aeosta, J. L. (2004). Structural Characterization of Polymer Blends Based on Polysulfones J. Appl. Pofym. Sci, 92(5), 3030-3039. 

Miscible polymer blends offer a physical method for tailoring properties to obtain combinations that may be more desirable than those of either component polymer. The water sorption and transport behavior of miscible polymer blends have been examined in several studies. For example, Schult and Paul [12] investigated the water sorption and transport properties of homogeneous blends of PVP, a water-soluble polymer that is miscible with a relatively hydrophobic bisphenol A polysulfone (PSF) over the entire composition range. Unfortunately this study was restricted to blends containing <40% PVP, since blends containing >40% PVP would phase-separate when exposed to high water vapor activities. Such phase-separation is driven by the fact that one polymer wishes to swell or dissolve in water, while the other does not. 

Kapantaidakis, G.C., Kaldis, S.P., Sakellaropoulos, G.P., Chira, E., Loppinet, B and Floudas, G. (1999) Interrelation between phase state and gas permeation in polysulfone/polyimide blend membranes. J. Polym. Sci. Part B Polym. Phys., 37, 2788-2798, 8. 

Ishihara et al. also investigated that polysulfone/MFC polymers blend membranes could improve blood compatibility and reduce protein adsorption and platelet adhesion [104-108]. Based on these results, the addition of the MFC polymer to the polysulfone should be a very useful method to improve the functions and blood compatibility. Ultrafiltration antifouling membranes were successfully prepared blending polyethersulfone with 2-methac-ryloyloxyethylphosphorylcholine (MFC) and n-butyl methacrylate (BMA) copolymer, by phase inversion method. IDue to the high hydrophilicity and electric neutrality of MFC-BMA copolymer, the... 

Trogadas and Ramani summarized the modification of PEM membranes, including Nafion modified by zirconium phosphates, heteropolyacids, hydrogen sulfates, metal oxides, and silica. Membranes with sulfonated non-fluorinated backbones were also described. The base polymers polysulfone, poly(ether sulfone), poly(ether ether ketone), polybenzimidazole, and polyimide. Another interesting category is acid-base polymer blend membranes. This review also paid special attention to electrode designs based on catalyst particles bound by a hydrophobic poly-tetrafluoroethylene (PTFE) structure or hydrophilic Nafion, vacuum deposition, and electrodeposition method. Issues related to the MEA were presented. In then-study on composite membranes, the effects of particle sizes, cation sizes, number of protons, etc., of HPA were correlated with the fuel cell performance. To promote stability of the PTA within the membrane matrix, the investigators have employed PTA supported on metal oxides such as silicon dioxide as additives to Nafion. 

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