Poly aryls, synthesis

Although the sulfone activated biphenyl and the ketone activated naphthalene moiety for the displacement polymerization have been reported by Attwood et al. [11], these were rediscovered by Cummings et al. [12] and Hergenrother et al. [13], respectively, for the synthesis of poly(aryl ethers). Recently, Singh and Hay [14] reported polymers containing 0-dibenzoyl benzene (1,2,3) moiety by reaction between bis(O-fluorobenzoyl) benzene or substituted benzene with bisphenates of alkali metal salt in DMAC as follows ... 

It is interesting to note that all the new aromatic systems, as described, undergo displacement polymerizations in DMAC solvent by the K2CO3 method, except perfluoroalkylene [10] and amide activated polymerization [9], which were performed in NMP solvent. The displacement polymerization in DMAC solvent was carried out at 155-164°C. poly(aryl ether ketones) require less reaction time (3-6 h) than other aromatic systems for synthesis of polyethers [15]. Synthesis of the fluorinated polyether as reported by Irvin et al. [16] was carried out at room temperature for 16 h (Mw = 75,000), whereas the same polymer by Mercer et al. [17] was synthesized at 120°C for 17 h (Mw = 78,970). 

Diphenol/thiophenol is one of the most important polymer precursors for synthesis of poly(aryl ethers) or poly-(aryl sulfides) in displacement polymerizations. Commonly used bisphenols are 4,4 -isopropylidene diphenol or bisphenol-A (BPA) due to their low price and easy availability. Other commercial bisphenols have also been reported [7,24,25]. Recently, synthesis of poly(aryl ethers) by the reaction of new bisphenol monomers with activated aromatic dihalides has been reported. The structures of the polymer precursors are described in Table 2. Poly(aryl ether phenylquinoxalines) have been synthesized by Connell et al. [26], by the reaction of bisphenols containing a preformed quinoxaline ring with... 

The use of other heterocyclic rings in displacement polymerization has been recently reported. Table 3 shows the new dihalo heterocyclic monomers used for synthesis of poly(aryl ethers). 

Poly(arylene thioether)s, 363-364 Poly(arylene thioether sulfone)s, 364 Poly(aryl sulfone) derivatives, 354 Poly(p-benzamide), synthesis of, 188-189 Polybenzimidazoles (PBIs), 265 ferrocene-containing, 315 synthesis of, 313... 

Synthesis of Poly(Aryl Ester)-Polysiloxane Segmented Copolymers 117)... 

Synthesis of Fluorinated Poly(Aryl Ether)s Containing 1,4-Naphthalene Moieties... 

On the basis of the above studies reported thus far, we have designed and synthesized a series of novel poly(aryl ether)s containing both hexafluoroisopropylidene and 1,4-naphthalene moieties. We found these new polyarylethers to have good solubility, high Tg s, and excellent thermal stability. We report herein the synthesis and characterization of these poly(aryl ether)s containing fluorinated 1,4-naphthalene moieties. 

Scheme 3. synthesis of fluorinated poly (aryl ether ketone )s 3-7... 

Brunelle, in Chapter 5, has provided a solution to the problem of quaternary ammonium catalysts being unstable at elevated temperatures in the presence of highly nucleophilic anions. He found that catalysts based on p-dialkylaminopyridinium salts are approximately one hundred times more stable than simple tetraalkylammonium salts and are useful even up to temperatures of 180 C. Especially valuable is the fact that under these conditions a variety of nucleophilic displacement reactions on aryl halides occurs, making possible the economical commercial synthesis of otherwise difficulty available poly aryl ethers and sulfides. 

Direct copolymerization techniques have also been employed in the s)m-thesis of sulfonated poly(aryl ether ketones),i i polyimides, i 5 and poly(benzoimidazoles). The synthesis of random disulfonated biphenol poly(arylene ether sulfone) copolymers (BPSH x where x represents the percentage of disulfonated diphenylsulfone moieties in the polymer versus unsulfonated diphenylsulfone moities) (14) is shown in Scheme 3.5. 

Recently the synthesis and characterization of novel fluorinated poly(aryl ether)s containing perfluorophenylene moieties " " was also reported. These fluorinated polyethers were prepared by reaction of decafluorobiphenyl with bisphenols. These polymers exhibit low dielectric constants, low moisture absorption, and excellent thermal and mechanical properties. Tough, transparent films of the polymers were prepared by solution-casting or compression-molding. The fluorinated poly(aryl ether)s containing perfluorophenylene moieties are good candidates for use as coatings in microelectronics applications. 

Synthesis of Heterocycle-Containing Poly (Aryl Ethers). 68... 

Three poly(aryl ethers) were prepared and used as coblocks in imide copolymerizations. The first coblock prepared was poly(aryl ether phenylquinoxaline), since this material has the requisite high Tg ( 280 °C) and thermal stability, and the polymer can be processed from solution or the melt. The synthesis of po-ly(aryl ether phenylquinoxalines) involves a fluoro-displacement polymerization of appropriately substituted fluorophenylquinoxalines with bisphenols, us-... 

The third poly(aryl ether) surveyed as a coblock for polyimide copolymerization was poly(aryl ether ether ketone), PEEK, which is a highly crystalline polymer (40-50 % crystallinity) with a Tg of 145 °C and a Tj of 340 °C. However, PEEK is only soluble in diphenylsulfone at temperatures in excess of 300 °C or in strong acids [50]. This insolubility in organic solvents makes the synthesis and... 

The synthesis of the bis(amino) aryl ether ketimine oligomer was carried out in an analogous fashion to the poly(aryl ether) oligomers described before (Scheme 5) [43]. The ketimine functional 4,4 -bisfluoride was reacted with hyd-roquinone and 3-aminophenol in an NMP/toluene solvent mixture in the presence of potassium carbonate. The characteristics of the oHgomer synthesized are shown in Table 1 (sample le). 

Tomalia s exhaustive review paper with coloured illustrations [10] did much to popularise the highly branched compounds and to ensure broad general acceptance of the family name dendrimers . In the same year, Frechet and Hawker described the first convergent synthesis of dendrimers. They constructed poly(aryl ether) architectures from the outside inwards (Fig. 1.6 see Section 2.2) [15]. 

---