Nucleophilic polycondensation

The nucleophilic polycondensation has the advantage that the chemical structure and thus the properties of the poly(ether sulfone)s can be varied in a relatively simple way through the selection of the bisphenol components. 

Several different approaches to the construction of poly(arylene-carborane)s were initially considered (Scheme 1). These included (i) nucleophilic polycondensation between a bis-phenol and an activated, carborane-based dihalide in the presence of base, a reaction used for the synthesis of commercial polyetherketones and polyethersulfones,4 (ii) electrophilic polycondensation between an aromatic diacid and a carborane-based diarylether in the presence of a strong-acid catalyst,5 and (iii) direct, homogeneously-catalysed coupling of a carborane-based dihalide.6 However,... 

Novel sulfonated PEKs were prepared directly by nucleophilic polycondensation of 4,4 -sulfonyldiphenol with various ratios of 4,4 -difluorobenzo-phenone to 5,5 -carbonyl-bis-(2-fluorobenzenesulfonate) in DMSO [108]. 

Sulfonated poly(phthalazinone ether ketones) were synthesized directly by aromatic nucleophilic polycondensation of 4-(4-hydroxyphenyl)phthalazino-ne with various ratios of 5,5 -carbonylbis-(2-fluorobenzenesulfonate) or 4,4 -difluorobenzophenone [109]. 

Nucleophilic displacement chemistry involving aromatic dihalides and bisphenois, represented the first means by which high molecular weight aromatic polyethers could be produced. This technology has since been the basis for all commercial processes developed for this family of Engineering Polymers. The preparative method involves the nucleophilic polycondensation of a bispheno salt with an activated aromatic dihalide in an aprotic solvent. Further investigations have shown that the method has a very wide scope and that it can be applied to the preparation of a host of aromatic poly (sulfone ethers), poly (ketone ethers) and other related polyethers. 

Our initial investigation was centered around the preparation of high molecular weight poly(biphenylene ether sulfone) (8) this material can be prepared by the nucleophilic polycondensation shown in equation (III) ... 

FTIR was used to characterize the structure of Ad-PAENKs. The characteristic absorption bands of aryl carbonyl groups appeared near 1660 cm and that of aryl ether linkages at 1220 cm" the characteristic absorption bands of adamantyl groups appeared at about 2920 cm" (—CH —) and 2850 cm" (—CH —), and proved that the adamantyl groups were successfully incorporated into the polymers, which confirmed that the nucleophilic polycondensations proceeded, leading to the formation of Ad-PAENKs. 

The Chinese patented polyetherketone and polyethersulfone (PEK-C PES-C) are amorphous polymers with high glass transition temperatures (Tj,=228°Cand 260 C respectively)("7-i. They were synthesized by nucleophilic polycondensation of phenolphthalein (PPH) and dichlorobenzophenone or dichlorodiphenylsulfone in sulfolane in the presence of potassium carbonate. They were found to be good membrane materials for ultrafiltration and microfiltration( and could also be used as charged membranes (after sulfonation or chloromethylation/quaternization) for nanofiltration and electrodialysis processes. 

Fig. 19 Synthesis of poly(ethersulfone)s by A Friedel-Crafts sulfonylation and B by nucleophilic polycondensation in solution using phenolates and C melt polycondensation using trimethylsUyl derivatives of bisphenols... 

A series of sulfonated poly(arylene ether nitrile ketone) membranes, thermally stable up to 300°C, have been made by aromatic nucleophilic polycondensation of... 

FIG. 3.14 Synthesis of poly(ether suIfone)s by (a) Friedel Crafts sulfonylation. (b) nucleophilic polycondensation in solution using phenolates. and (c) melt polycondensalion using trimethylsilyl derivatives of bisphenols. 

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