Polysulfone synthesis

Syntheses. The presence of the ether and imide functionalities provides two general approaches for synthesis. Polyetherimides can be prepared by a nucleophilic displacement polymerization similar to the halide displacement in polysulfone synthesis or by a condensation of dianhydrides and diamines that is similar to normal polyimide synthesis (see Polyimides). 

Palladium catalysts also promote copolymerization of SO2 with alkenes analogously to copolymerization of CO and alkenes (Eq. 7.24) [119]. The catalyst activities for the polysulfone synthesis are lower by an order of magnitude than those for the polyketone synthesis. Perfectly alternating copolymers can be obtained by use of cationic methylpalladium(II) complexes, [PdMe(CH3CN)L2]BF4 (L2 = l,3-bis(diphenylphosphino)propane and 1,2-bis(2,5-dimethylphosphinolato)benzene), in contrast to a lower degree of alternation provided by a radical polymerization [120]. 

Table 9.1 Properties of hypercrosslinked polysulfone. Synthesis conditions 80°C, 12 h, ethylene dichloride, SnCU...

Nucleophilic Substitution Route. Commercial synthesis of poly(arylethersulfone)s is accompHshed almost exclusively via the nucleophilic substitution polycondensation route. This synthesis route, discovered at Union Carbide in the early 1960s (3,4), involves reaction of the bisphenol of choice with 4,4 -dichlorodiphenylsulfone in a dipolar aprotic solvent in the presence of an alkaUbase. Examples of dipolar aprotic solvents include A/-methyl-2-pyrrohdinone (NMP), dimethyl acetamide (DMAc), sulfolane, and dimethyl sulfoxide (DMSO). Examples of suitable bases are sodium hydroxide, potassium hydroxide, and potassium carbonate. In the case of polysulfone (PSE) synthesis, the reaction is a two-step process in which the dialkah metal salt of bisphenol A (1) is first formed in situ from bisphenol A [80-05-7] by reaction with the base (eg, two molar equivalents of NaOH),... 

As a variation on the base-catalyzed nucleopbilic displacement chemistry described, polysulfones and other polyarylethers have been prepared by cuprous chloride-catalyzed polycondensation of aromatic dihydroxy compounds with aromatic dibromo compounds. The advantage of this route is that it does not require that the aromatic dibromo compound be activated by an electron-withdrawing group such as the sulfone group. Details of this polymerization method, known as the Ullmaim synthesis, have been described (8). 

Other Synthesis Routes. Several alternative routes to the nucleopbilic substitution synthesis of polysulfones are possible. Polyethersulfone can be synthesized by the electrophilic Eriedel-Crafts reaction of bis(4-chlorosulfonylphen5l)ether [121 -63-1] with diphenyl ether [101-84-8] (11—13). 

Similar to the synthesis of polysulfones, poly(arylene ether ketone)s can also be prepared by using either AA and BB monomers or an AB monomer. 

Scheme 6.11 Typical nucleophilic synthesis of bisphenol A polysulfone.

The nucleophilic aromatic substitution reaction for the synthesis of poly(arylene ether ketone)s is similar to that of polysulfone, involving aromatic dihalides and aromatic diphenolates. Since carbonyl is a weaker electron-withdrawing group titan sulfonyl, in most cases, difluorides need to be used to afford high-molecular-weight polymers. Typically potassium carbonate is used as a base to avoid the... 

Bisphenol-A benzoxazine reaction, under acidic conditions, 416-417 Bisphenol-A polyarylates, 77 synthesis of, 109-113 Bisphenol-A polysulfone, 327 nucleophilic synthesis of, 337 Bisphenolic monomer, 354 Biurets, 227... 

Nucleophilic displacement, PQ and PPQ synthesis by, 310-311 Nucleophilic substitution, 10, 282, 283 hyperbranched polyimides via, 308 Nucleophilic synthesis, of bisphenol-A polysulfone, 337... 

See also PBT degradation structure and properties of, 44-46 synthesis of, 106, 191 Polycaprolactam (PCA), 530, 541 Poly(e-caprolactone) (CAPA, PCL), 28, 42, 86. See also PCL degradation OH-terminated, 98-99 Polycaprolactones, 213 Poly(carbo[dimethyl]silane)s, 450, 451 Polycarbonate glycols, 207 Polycarbonate-polysulfone block copolymer, 360 Polycarbonates, 213 chemical structure of, 5 Polycarbosilanes, 450-456 Poly(chlorocarbosilanes), 454 Polycondensations, 57, 100 Poly(l,4-cyclohexylenedimethylene terephthalate) (PCT), 25 Polydimethyl siloxanes, 4 Poly(dioxanone) (PDO), 27 Poly (4,4 -dipheny lpheny lpho sphine oxide) (PAPO), 347 Polydispersity, 57 Polydispersity index, 444 Poly(D-lactic acid) (PDLA), 41 Poly(DL-lactic acid) (PDLLA), 42 Polyester amides, 18 Polyester-based networks, 58-60 Polyester carbonates, 18 Polyester-ether block copolymers, 20 Polyester-ethers, 26... 

Frederick Frey and Walter Shultze were instrumental early researchers. Frey was among the first to dehydrogenate paraffins catalytically to olefins and then the olefins to diolefins that serve as feedstocks to the production of many of today s polymers. In competition with Bakelite, he discovered the preparation of polysulfone polymers made from the reaction of sulfur dioxide and olefins creating a hard Bakelite-like material. Frey and Schultz also developed a process that allowed the production of 1,3-butadiene from butane that allowed the synthesis of SR. 

In addition to sulfone, phenyl units, and ether moieties, the main backbone of polysulfones can contain a number of other connecting units. The most notable such connecting group is the isopropylidene linkage which is part of the repeat unit of the well-known bisphenol A-based polysulfone. It is difficult to clearly describe the chemical makeup of polysulfones without reference to the chemistry used to synthesize them. There are several routes for the synthesis of polysulfones, but the one which has proved to be most practical and versatile over the years is by aromatic nucleophilic substitution. This polycondensation route is based on reaction of essentially equimolar quantities of 4,4,-dihalodiphenylsulfone (usually dichlorodiphenylsulfone (DCDPS)) with a bisphenol in the presence of base thereby forming the aromatic ether bonds and eliminating an alkali salt as a by-product. This route is employed almost exclusively for the manufacture of polysulfones on a commercial scale. 

The oligomer molecular weights were characterized by both UV-visible spectra (20, 21) and/or potentiometric titrations (22, 23). Details of the measurements are provided in these papers. The block copolymers also were characterized by intrinsic viscosity and in some cases by membrane osmometry and gel permeation chromatography. Additional characterization studies are continuing and will be reported later. A typical synthesis of a 5000-5000 polysulfone-S-polycarbonate-A copolymer via interfaciar polymerization is described below. 

The synthesis of polysulfone/poly(dimethylsiloxane) block copolymers was reported earlier (4, 5). Blends of the block copolymer with... 

Figure 1. Synthesis of polysulfone-poly(dimethylsiloxane) block copolymers...

Aromatic polysulfones are a commercially important class of thermoplastic polymers [127]. They have highly desirable qualities such as chemical inertness, thermal stability, and flame retardency [128,129]. Although a number of methods are available for the synthesis of polysulfones [130,131,132], step polymerization methods are the most widely used industrially [127]. Polysulfones have been synthesized with the involvement of sulfonylium cations as propagating species. 

Rodemann K and Staude E. Synthesis and characterization of affinity membranes made from polysulfone. J. Membr. Sci. 1994 88 271-278. 

The combinatorial synthesis based on the combination of microfluidics and electropolymerization was realized with a microchip consisting of two areas microfluidic channels for generation of gradient of two substances and a parallel electrochemical reactor with platinum electrodes (Fig. 13.3). The system was tested for synthesis of polyaniline in the presence of polysulfonic acid. The reagent ratio providing the best efficiency of the polymer synthesis was evaluated. 

Molybdophosphoric acid was also used to prepare HPA-polymer composite film catalysts, using polyphenylene oxide, polyethersulfone and polysulfone as polymers [4], The membrane-like materials were tested as catalysts in the liquid-phase synthesis of tert-butanol from isobutene and water, showing higher catalytic activity than the bulk acid. 

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