Polyether sulfone synthesis

Table 11 describes the thermal properties of polyether sulfone based on DCDPS and heteroarylenediol. The TgS range from 230 to 315°C and the decomposition temperature is higher than 450°C. Their thermal stability depends on the bisphenol and activated difluoride used in the polymer synthesis (Tables 10 and 11). 

This paper reviews some of our work on general methods for the synthesis of polyaromatics containing either terminal or pendant styrene groups and their thermal polymerization. The examples provided in this paper refer to an aromatic polyether sulfone (PSU) and poly-(2,6-dimethy1-1,4-phenylene oxide) (PPO). 

An example for the synthesis of poly(2,6-dimethyl-l,4-phenylene oxide) - aromatic poly(ether-sulfone) - poly(2,6-dimethyl-1,4-pheny-lene oxide) ABA triblock copolymer is presented in Scheme 6. Quantitative etherification of the two polymer chain ends has been accomplished under mild reaction conditions detailed elsewhere(11). Figure 4 presents the 200 MHz Ir-NMR spectra of the co-(2,6-dimethyl-phenol) poly(2,6-dimethyl-l,4-phenylene oxide), of the 01, w-di(chloroally) aromatic polyether sulfone and of the obtained ABA triblock copolymers as convincing evidence for the quantitative reaction of the parent pol3rmers chain ends. Additional evidence for the very clean synthetic procedure comes from the gel permeation chromatograms of the two starting oligomers and of the obtained ABA triblock copolymer presented in Figure 5. 

Two di(electrophilic) macromers were prepared and functionalized with 2-oxazollne chain ends. a,o)-Di(chloroallyl) aromatic polyether sulfone (PSU-CA) and a,o)-di(bromobenzyl) aromatic polyether sulfone (PSU-BX) were prepared by the phase transfer catalyzed reaction (in chlorobenzene, 12% aqueous NaOH) of a,o)-di(phenol) PSU with cis-1,4-dichloro-2-butene and a,a -dlbromo-p-xylene respectively (Scheme 2). a,o)-Dl(phenol) PSU was prepared from bisphenol-A and 4,4 -dichlorodiphenyl sulfone.The detailed synthesis and characterization of a,w-di(electrophilic) PSU has been described previously. However, it is important to mention here that in order to achieve quantitative functionalization of the pol3oner chain ends it is necessary to carry out the reaction in aromatic solvents, in the presence of stoichiometric amounts of phase transfer catalyst versus phenol chain ends, and in the presence of relatively dilute aqueous NaOH solution. Using high... 

Scheme 2. Synthesis of a,w-di(electrophilic) aromatic polyether sulfones.

Solvent for Displacement Reactions. As the most polar of the common aprotic solvents, DMSO is a favored solvent for displacement reactions because of its high dielectric constant and because anions are less solvated in it (87). Rates for these reactions are sometimes a thousand times faster in DMSO than in alcohols. Suitable nucleophiles include acetyUde ion, alkoxide ion, hydroxide ion, azide ion, carbanions, carboxylate ions, cyanide ion, hahde ions, mercaptide ions, phenoxide ions, nitrite ions, and thiocyanate ions (31). Rates of displacement by amides or amines are also greater in DMSO than in alcohol or aqueous solutions. Dimethyl sulfoxide is used as the reaction solvent in the manufacture of high performance, polyaryl ether polymers by reaction of bis(4,4 -chlorophenyl) sulfone with the disodium salts of dihydroxyphenols, eg, bisphenol A or 4,4 -sulfonylbisphenol (88). These and related reactions are made more economical by efficient recycling of DMSO (89). Nucleophilic displacement of activated aromatic nitro groups with aryloxy anion in DMSO is a versatile and useful reaction for the synthesis of aromatic ethers and polyethers (90). 

Polyether-PA segmented copolymers, synthesizing, 191-192 Polyether polyols, 200, 205, 211-212 synthesis of, 223, 224 Poly(ether sulfone) (PES), 327. See also Poly(arylene ether sulfone)s Poly(phenylene ether sulfone) chains Sulfonated poly (ary lene ether sulfone)... 

Membrane research is a rather diverse field, exploiting perfluorinated iono-mers, hydrocarbon and aromatic polymers, and acid-base polymer complexes. Polyether and polyketo polymers with statistically sulfonated phenylene groups such as sPEK, sPEEK, and sPEEKK or polymers on the basis of benzimidazole have been tested as well. Recent reviews on membrane synthesis and experimental characterization can be found in the literature. ... 

A series of polyphosphites, polyphosphates, polythiophosphates, and other polymers containing sulfone functions, based on 1, have also been described [17,119]. An efficient synthesis of polyethers from 1 and 1,8-dibromo or dimesyl octane by microwave-assisted phase transfer catalysis has been reported [120]. 

The polyetherification route to polyethersulfones can be adapted to the synthesis of polyethers containing strongly electron-withdrawing groups other than sulfone groups. Poly(l,4-oxyphenylenecarbonyl-l,4-phenylene) [27380-27 4] (6) is produced by condensation of 4,4 -dihydroxybenzophenone or by the self-condensation of 4-chloro-4 -hydroxybenzophenone. It has a melting point of 367°C and a glass-transition temperature of 154°C (83). 

Because the procedure used in making these polymers is similar (10), it is sufficient to describe one, namely, the synthesis of the ter-polyether from bisphenol A, diphenolic acid, and dichlorodiphenyl sulfone, whose polymerization scheme is ... 

Synthesis of (+)-Eurylene. The reaction of a-sulfonyl anions with carboxylic acid derivatives is used as the key step in the construction of various natural products. The resulting (3-oxo sulfone intermediate is then further elaborated and/or desulfonylated to afford the desired product. A variety of carboxylic acid derivatives has been used, esters being most often employed, as depicted in Eq. 149 for the synthesis of the triterpene polyether (+)-eurylene.149... 

Greene observed that the formation of 18-crown-6 from a ditosylate and a diol in the presence of f-butoxide salts was enhanced when a potassium cation was used (Greene, 1972). This template effect was operative for the synthesis of other polyether crown compounds using alkali or alkaline-earth metal cations. Template effects have also been observed for the preparation of aza-crown ethers, although the effect is less pronounced because the softer A-donor atoms form weaker complexes with the alkali metal cations (Frens-dorff, 1971). Richman and Atkins reported that high-dilution techniques were not required for the cyclization reaction of the disodium salt of a pertosylated oligoethylenepolyamine with sulfonated diols to form medium and large polyaza-crown compounds (Richman and Atkins, 1974 Atkins et al., 1978). 

New phosphorus containing polysulfones could be obtained by using different phosphorus containing diols in the classical synthesis of PSF (Scheme 6.4). Diols can contain phosphorus in main chain position or incorporate in a phenanthrene-type ring as side chain. These different phosphorus-containing diols form aromatic polyethers by polycondensation with dihalogen-substituted aromatic sulfones [48]. The chain structure of the polymer (aromatic or aliphatic) and the position of phosphorus in the chain influence the polymer properties (electroluminescence [49,50], flame retardancy [51], liquid crystal properties [52]). 

---